RubyGems: Enable Style/StringLiterals cop

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

137 files changed, 1324 insertions, 1324 deletions

diff --git a/lib/rubygems/basic_specification.rb b/lib/rubygems/basic_specification.rb
index b3b63b51aa..526a5069c2 100644
--- a/lib/rubygems/basic_specification.rb
+++ b/lib/rubygems/basic_specification.rb
@@ -47,7 +47,7 @@ class Gem::BasicSpecification
   # directory.
 
   def gem_build_complete_path # :nodoc:
-    File.join extension_dir, 'gem.build_complete'
+    File.join extension_dir, "gem.build_complete"
   end
 
   ##
@@ -103,7 +103,7 @@ class Gem::BasicSpecification
 
   def extensions_dir
     Gem.default_ext_dir_for(base_dir) ||
-      File.join(base_dir, 'extensions', Gem::Platform.local.to_s,
+      File.join(base_dir, "extensions", Gem::Platform.local.to_s,
                 Gem.extension_api_version)
   end
 
diff --git a/lib/rubygems/command.rb b/lib/rubygems/command.rb
index f74cb419f9..9fc3360fa1 100644
--- a/lib/rubygems/command.rb
+++ b/lib/rubygems/command.rb
@@ -5,9 +5,9 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'optparse'
-require_relative 'requirement'
-require_relative 'user_interaction'
+require_relative "optparse"
+require_relative "requirement"
+require_relative "user_interaction"
 
 ##
 # Base class for all Gem commands.  When creating a new gem command, define
@@ -76,7 +76,7 @@ class Gem::Command
     when Array
       @extra_args = value
     when String
-      @extra_args = value.split(' ')
+      @extra_args = value.split(" ")
     end
   end
 
@@ -556,7 +556,7 @@ class Gem::Command
   def configure_options(header, option_list)
     return if option_list.nil? or option_list.empty?
 
-    header = header.to_s.empty? ? '' : "#{header} "
+    header = header.to_s.empty? ? "" : "#{header} "
     @parser.separator "  #{header}Options:"
 
     option_list.each do |args, handler|
@@ -565,7 +565,7 @@ class Gem::Command
       end
     end
 
-    @parser.separator ''
+    @parser.separator ""
   end
 
   ##
@@ -578,13 +578,13 @@ class Gem::Command
   # ----------------------------------------------------------------
   # Add the options common to all commands.
 
-  add_common_option('-h', '--help',
-                    'Get help on this command') do |value, options|
+  add_common_option("-h", "--help",
+                    "Get help on this command") do |value, options|
     options[:help] = true
   end
 
-  add_common_option('-V', '--[no-]verbose',
-                    'Set the verbose level of output') do |value, options|
+  add_common_option("-V", "--[no-]verbose",
+                    "Set the verbose level of output") do |value, options|
     # Set us to "really verbose" so the progress meter works
     if Gem.configuration.verbose and value
       Gem.configuration.verbose = 1
@@ -593,7 +593,7 @@ class Gem::Command
     end
   end
 
-  add_common_option('-q', '--quiet', 'Silence command progress meter') do |value, options|
+  add_common_option("-q", "--quiet", "Silence command progress meter") do |value, options|
     Gem.configuration.verbose = false
   end
 
@@ -606,20 +606,20 @@ class Gem::Command
   # commands.  Both options are actually handled before the other
   # options get parsed.
 
-  add_common_option('--config-file FILE',
-                    'Use this config file instead of default') do
+  add_common_option("--config-file FILE",
+                    "Use this config file instead of default") do
   end
 
-  add_common_option('--backtrace',
-                    'Show stack backtrace on errors') do
+  add_common_option("--backtrace",
+                    "Show stack backtrace on errors") do
   end
 
-  add_common_option('--debug',
-                    'Turn on Ruby debugging') do
+  add_common_option("--debug",
+                    "Turn on Ruby debugging") do
   end
 
-  add_common_option('--norc',
-                    'Avoid loading any .gemrc file') do
+  add_common_option("--norc",
+                    "Avoid loading any .gemrc file") do
   end
 
   # :stopdoc:
diff --git a/lib/rubygems/command_manager.rb b/lib/rubygems/command_manager.rb
index e421f89884..9d49138ae7 100644
--- a/lib/rubygems/command_manager.rb
+++ b/lib/rubygems/command_manager.rb
@@ -5,9 +5,9 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'command'
-require_relative 'user_interaction'
-require_relative 'text'
+require_relative "command"
+require_relative "user_interaction"
+require_relative "text"
 
 ##
 # The command manager registers and installs all the individual sub-commands
@@ -73,9 +73,9 @@ class Gem::CommandManager
   ].freeze
 
   ALIAS_COMMANDS = {
-    'i'      => 'install',
-    'login'  => 'signin',
-    'logout' => 'signout',
+    "i"      => "install",
+    "login"  => "signin",
+    "logout" => "signout",
   }.freeze
 
   ##
@@ -104,7 +104,7 @@ class Gem::CommandManager
   # Register all the subcommands supported by the gem command.
 
   def initialize
-    require 'timeout'
+    require "timeout"
     @commands = {}
 
     BUILTIN_COMMANDS.each do |name|
@@ -169,10 +169,10 @@ class Gem::CommandManager
     end
 
     case args.first
-    when '-h', '--help' then
+    when "-h", "--help" then
       say Gem::Command::HELP
       terminate_interaction 0
-    when '-v', '--version' then
+    when "-v", "--version" then
       say Gem::VERSION
       terminate_interaction 0
     when /^-/ then
diff --git a/lib/rubygems/commands/build_command.rb b/lib/rubygems/commands/build_command.rb
index 6d1a057dfa..accbd7e97d 100644
--- a/lib/rubygems/commands/build_command.rb
+++ b/lib/rubygems/commands/build_command.rb
@@ -1,29 +1,29 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../package'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../package"
+require_relative "../version_option"
 
 class Gem::Commands::BuildCommand < Gem::Command
   include Gem::VersionOption
 
   def initialize
-    super 'build', 'Build a gem from a gemspec'
+    super "build", "Build a gem from a gemspec"
 
     add_platform_option
 
-    add_option '--force', 'skip validation of the spec' do |value, options|
+    add_option "--force", "skip validation of the spec" do |value, options|
       options[:force] = true
     end
 
-    add_option '--strict', 'consider warnings as errors when validating the spec' do |value, options|
+    add_option "--strict", "consider warnings as errors when validating the spec" do |value, options|
       options[:strict] = true
     end
 
-    add_option '-o', '--output FILE', 'output gem with the given filename' do |value, options|
+    add_option "-o", "--output FILE", "output gem with the given filename" do |value, options|
       options[:output] = value
     end
 
-    add_option '-C PATH', 'Run as if gem build was started in <PATH> instead of the current working directory.' do |value, options|
+    add_option "-C PATH", "Run as if gem build was started in <PATH> instead of the current working directory." do |value, options|
       options[:build_path] = value
     end
   end
diff --git a/lib/rubygems/commands/cert_command.rb b/lib/rubygems/commands/cert_command.rb
index b59564d575..56bf5ce689 100644
--- a/lib/rubygems/commands/cert_command.rb
+++ b/lib/rubygems/commands/cert_command.rb
@@ -1,69 +1,69 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../security'
+require_relative "../command"
+require_relative "../security"
 
 class Gem::Commands::CertCommand < Gem::Command
   def initialize
-    super 'cert', 'Manage RubyGems certificates and signing settings',
+    super "cert", "Manage RubyGems certificates and signing settings",
           :add => [], :remove => [], :list => [], :build => [], :sign => []
 
-    add_option('-a', '--add CERT',
-               'Add a trusted certificate.') do |cert_file, options|
+    add_option("-a", "--add CERT",
+               "Add a trusted certificate.") do |cert_file, options|
       options[:add] << open_cert(cert_file)
     end
 
-    add_option('-l', '--list [FILTER]',
-               'List trusted certificates where the',
-               'subject contains FILTER') do |filter, options|
-      filter ||= ''
+    add_option("-l", "--list [FILTER]",
+               "List trusted certificates where the",
+               "subject contains FILTER") do |filter, options|
+      filter ||= ""
 
       options[:list] << filter
     end
 
-    add_option('-r', '--remove FILTER',
-               'Remove trusted certificates where the',
-               'subject contains FILTER') do |filter, options|
+    add_option("-r", "--remove FILTER",
+               "Remove trusted certificates where the",
+               "subject contains FILTER") do |filter, options|
       options[:remove] << filter
     end
 
-    add_option('-b', '--build EMAIL_ADDR',
-               'Build private key and self-signed',
-               'certificate for EMAIL_ADDR') do |email_address, options|
+    add_option("-b", "--build EMAIL_ADDR",
+               "Build private key and self-signed",
+               "certificate for EMAIL_ADDR") do |email_address, options|
       options[:build] << email_address
     end
 
-    add_option('-C', '--certificate CERT',
-               'Signing certificate for --sign') do |cert_file, options|
+    add_option("-C", "--certificate CERT",
+               "Signing certificate for --sign") do |cert_file, options|
       options[:issuer_cert] = open_cert(cert_file)
       options[:issuer_cert_file] = cert_file
     end
 
-    add_option('-K', '--private-key KEY',
-               'Key for --sign or --build') do |key_file, options|
+    add_option("-K", "--private-key KEY",
+               "Key for --sign or --build") do |key_file, options|
       options[:key] = open_private_key(key_file)
     end
 
-    add_option('-A', '--key-algorithm ALGORITHM',
-               'Select which key algorithm to use for --build') do |algorithm, options|
+    add_option("-A", "--key-algorithm ALGORITHM",
+               "Select which key algorithm to use for --build") do |algorithm, options|
       options[:key_algorithm] = algorithm
     end
 
-    add_option('-s', '--sign CERT',
-               'Signs CERT with the key from -K',
-               'and the certificate from -C') do |cert_file, options|
+    add_option("-s", "--sign CERT",
+               "Signs CERT with the key from -K",
+               "and the certificate from -C") do |cert_file, options|
       raise Gem::OptionParser::InvalidArgument, "#{cert_file}: does not exist" unless
         File.file? cert_file
 
       options[:sign] << cert_file
     end
 
-    add_option('-d', '--days NUMBER_OF_DAYS',
-               'Days before the certificate expires') do |days, options|
+    add_option("-d", "--days NUMBER_OF_DAYS",
+               "Days before the certificate expires") do |days, options|
       options[:expiration_length_days] = days.to_i
     end
 
-    add_option('-R', '--re-sign',
-               'Re-signs the certificate from -C with the key from -K') do |resign, options|
+    add_option("-R", "--re-sign",
+               "Re-signs the certificate from -C with the key from -K") do |resign, options|
       options[:resign] = resign
     end
   end
@@ -93,7 +93,7 @@ class Gem::Commands::CertCommand < Gem::Command
 
   def open_private_key(key_file)
     check_openssl
-    passphrase = ENV['GEM_PRIVATE_KEY_PASSPHRASE']
+    passphrase = ENV["GEM_PRIVATE_KEY_PASSPHRASE"]
     key = OpenSSL::PKey.read File.read(key_file), passphrase
     raise Gem::OptionParser::InvalidArgument,
       "#{key_file}: private key not found" unless key.private?
@@ -166,10 +166,10 @@ class Gem::Commands::CertCommand < Gem::Command
   def build_key # :nodoc:
     return options[:key] if options[:key]
 
-    passphrase = ask_for_password 'Passphrase for your Private Key:'
+    passphrase = ask_for_password "Passphrase for your Private Key:"
     say "\n"
 
-    passphrase_confirmation = ask_for_password 'Please repeat the passphrase for your Private Key:'
+    passphrase_confirmation = ask_for_password "Please repeat the passphrase for your Private Key:"
     say "\n"
 
     raise Gem::CommandLineError,
@@ -260,7 +260,7 @@ For further reading on signing gems see `ri Gem::Security`.
   def load_default_key
     key_file = File.join Gem.default_key_path
     key = File.read key_file
-    passphrase = ENV['GEM_PRIVATE_KEY_PASSPHRASE']
+    passphrase = ENV["GEM_PRIVATE_KEY_PASSPHRASE"]
     options[:key] = OpenSSL::PKey.read key, passphrase
 
   rescue Errno::ENOENT
diff --git a/lib/rubygems/commands/check_command.rb b/lib/rubygems/commands/check_command.rb
index 3b6b97ae3b..4d1f8782b1 100644
--- a/lib/rubygems/commands/check_command.rb
+++ b/lib/rubygems/commands/check_command.rb
@@ -1,44 +1,44 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../version_option'
-require_relative '../validator'
-require_relative '../doctor'
+require_relative "../command"
+require_relative "../version_option"
+require_relative "../validator"
+require_relative "../doctor"
 
 class Gem::Commands::CheckCommand < Gem::Command
   include Gem::VersionOption
 
   def initialize
-    super 'check', 'Check a gem repository for added or missing files',
+    super "check", "Check a gem repository for added or missing files",
           :alien => true, :doctor => false, :dry_run => false, :gems => true
 
-    add_option('-a', '--[no-]alien',
+    add_option("-a", "--[no-]alien",
                'Report "unmanaged" or rogue files in the',
-               'gem repository') do |value, options|
+               "gem repository") do |value, options|
       options[:alien] = value
     end
 
-    add_option('--[no-]doctor',
-               'Clean up uninstalled gems and broken',
-               'specifications') do |value, options|
+    add_option("--[no-]doctor",
+               "Clean up uninstalled gems and broken",
+               "specifications") do |value, options|
       options[:doctor] = value
     end
 
-    add_option('--[no-]dry-run',
-               'Do not remove files, only report what',
-               'would be removed') do |value, options|
+    add_option("--[no-]dry-run",
+               "Do not remove files, only report what",
+               "would be removed") do |value, options|
       options[:dry_run] = value
     end
 
-    add_option('--[no-]gems',
-               'Check installed gems for problems') do |value, options|
+    add_option("--[no-]gems",
+               "Check installed gems for problems") do |value, options|
       options[:gems] = value
     end
 
-    add_version_option 'check'
+    add_version_option "check"
   end
 
   def check_gems
-    say 'Checking gems...'
+    say "Checking gems..."
     say
     gems = get_all_gem_names rescue []
 
@@ -57,7 +57,7 @@ class Gem::Commands::CheckCommand < Gem::Command
   end
 
   def doctor
-    say 'Checking for files from uninstalled gems...'
+    say "Checking for files from uninstalled gems..."
     say
 
     Gem.path.each do |gem_repo|
@@ -72,11 +72,11 @@ class Gem::Commands::CheckCommand < Gem::Command
   end
 
   def arguments # :nodoc:
-    'GEMNAME       name of gem to check'
+    "GEMNAME       name of gem to check"
   end
 
   def defaults_str # :nodoc:
-    '--gems --alien'
+    "--gems --alien"
   end
 
   def description # :nodoc:
diff --git a/lib/rubygems/commands/cleanup_command.rb b/lib/rubygems/commands/cleanup_command.rb
index dc181e4de0..7f143999eb 100644
--- a/lib/rubygems/commands/cleanup_command.rb
+++ b/lib/rubygems/commands/cleanup_command.rb
@@ -1,35 +1,35 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../dependency_list'
-require_relative '../uninstaller'
+require_relative "../command"
+require_relative "../dependency_list"
+require_relative "../uninstaller"
 
 class Gem::Commands::CleanupCommand < Gem::Command
   def initialize
-    super 'cleanup',
-          'Clean up old versions of installed gems',
+    super "cleanup",
+          "Clean up old versions of installed gems",
           :force => false, :install_dir => Gem.dir,
           :check_dev => true
 
-    add_option('-n', '-d', '--dry-run',
-               'Do not uninstall gems') do |value, options|
+    add_option("-n", "-d", "--dry-run",
+               "Do not uninstall gems") do |value, options|
       options[:dryrun] = true
     end
 
-    add_option(:Deprecated, '--dryrun',
-               'Do not uninstall gems') do |value, options|
+    add_option(:Deprecated, "--dryrun",
+               "Do not uninstall gems") do |value, options|
       options[:dryrun] = true
     end
-    deprecate_option('--dryrun', extra_msg: 'Use --dry-run instead')
+    deprecate_option("--dryrun", extra_msg: "Use --dry-run instead")
 
-    add_option('-D', '--[no-]check-development',
-               'Check development dependencies while uninstalling',
-               '(default: true)') do |value, options|
+    add_option("-D", "--[no-]check-development",
+               "Check development dependencies while uninstalling",
+               "(default: true)") do |value, options|
       options[:check_dev] = value
     end
 
-    add_option('--[no-]user-install',
-               'Cleanup in user\'s home directory instead',
-               'of GEM_HOME.') do |value, options|
+    add_option("--[no-]user-install",
+               "Cleanup in user's home directory instead",
+               "of GEM_HOME.") do |value, options|
       options[:user_install] = value
     end
 
diff --git a/lib/rubygems/commands/contents_command.rb b/lib/rubygems/commands/contents_command.rb
index 716022c458..3dd0b16265 100644
--- a/lib/rubygems/commands/contents_command.rb
+++ b/lib/rubygems/commands/contents_command.rb
@@ -1,39 +1,39 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../version_option"
 
 class Gem::Commands::ContentsCommand < Gem::Command
   include Gem::VersionOption
 
   def initialize
-    super 'contents', 'Display the contents of the installed gems',
+    super "contents", "Display the contents of the installed gems",
           :specdirs => [], :lib_only => false, :prefix => true,
           :show_install_dir => false
 
     add_version_option
 
-    add_option('--all',
+    add_option("--all",
                "Contents for all gems") do |all, options|
       options[:all] = all
     end
 
-    add_option('-s', '--spec-dir a,b,c', Array,
+    add_option("-s", "--spec-dir a,b,c", Array,
                "Search for gems under specific paths") do |spec_dirs, options|
       options[:specdirs] = spec_dirs
     end
 
-    add_option('-l', '--[no-]lib-only',
+    add_option("-l", "--[no-]lib-only",
                "Only return files in the Gem's lib_dirs") do |lib_only, options|
       options[:lib_only] = lib_only
     end
 
-    add_option('--[no-]prefix',
+    add_option("--[no-]prefix",
                "Don't include installed path prefix") do |prefix, options|
       options[:prefix] = prefix
     end
 
-    add_option('--[no-]show-install-dir',
-               'Show only the gem install dir') do |show, options|
+    add_option("--[no-]show-install-dir",
+               "Show only the gem install dir") do |show, options|
       options[:show_install_dir] = show
     end
 
@@ -105,11 +105,11 @@ prefix or only the files that are requireable.
       case file
       when /\A#{spec.bindir}\//
         # $' is POSTMATCH
-        [RbConfig::CONFIG['bindir'], $']
+        [RbConfig::CONFIG["bindir"], $']
       when /\.so\z/
-        [RbConfig::CONFIG['archdir'], file]
+        [RbConfig::CONFIG["archdir"], file]
       else
-        [RbConfig::CONFIG['rubylibdir'], file]
+        [RbConfig::CONFIG["rubylibdir"], file]
       end
     end
   end
diff --git a/lib/rubygems/commands/dependency_command.rb b/lib/rubygems/commands/dependency_command.rb
index d2fed022fe..c9ddc9af0a 100644
--- a/lib/rubygems/commands/dependency_command.rb
+++ b/lib/rubygems/commands/dependency_command.rb
@@ -1,28 +1,28 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../local_remote_options'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../version_option"
 
 class Gem::Commands::DependencyCommand < Gem::Command
   include Gem::LocalRemoteOptions
   include Gem::VersionOption
 
   def initialize
-    super 'dependency',
-          'Show the dependencies of an installed gem',
+    super "dependency",
+          "Show the dependencies of an installed gem",
           :version => Gem::Requirement.default, :domain => :local
 
     add_version_option
     add_platform_option
     add_prerelease_option
 
-    add_option('-R', '--[no-]reverse-dependencies',
-               'Include reverse dependencies in the output') do
+    add_option("-R", "--[no-]reverse-dependencies",
+               "Include reverse dependencies in the output") do
       |value, options|
       options[:reverse_dependencies] = value
     end
 
-    add_option('-p', '--pipe',
+    add_option("-p", "--pipe",
                "Pipe Format (name --version ver)") do |value, options|
       options[:pipe_format] = value
     end
@@ -134,7 +134,7 @@ use with other commands.
 
   def ensure_local_only_reverse_dependencies # :nodoc:
     if options[:reverse_dependencies] and remote? and not local?
-      alert_error 'Only reverse dependencies for local gems are supported.'
+      alert_error "Only reverse dependencies for local gems are supported."
       terminate_interaction 1
     end
   end
@@ -142,7 +142,7 @@ use with other commands.
   def ensure_specs(specs) # :nodoc:
     return unless specs.empty?
 
-    patterns = options[:args].join ','
+    patterns = options[:args].join ","
     say "No gems found matching #{patterns} (#{options[:version]})" if
       Gem.configuration.verbose
 
@@ -151,10 +151,10 @@ use with other commands.
 
   def print_dependencies(spec, level = 0) # :nodoc:
     response = String.new
-    response << '  ' * level + "Gem #{spec.full_name}\n"
+    response << "  " * level + "Gem #{spec.full_name}\n"
     unless spec.dependencies.empty?
       spec.dependencies.sort_by {|dep| dep.name }.each do |dep|
-        response << '  ' * level + "  #{dep}\n"
+        response << "  " * level + "  #{dep}\n"
       end
     end
     response
diff --git a/lib/rubygems/commands/environment_command.rb b/lib/rubygems/commands/environment_command.rb
index b6b3d3812c..d95e1d0dbb 100644
--- a/lib/rubygems/commands/environment_command.rb
+++ b/lib/rubygems/commands/environment_command.rb
@@ -1,9 +1,9 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 class Gem::Commands::EnvironmentCommand < Gem::Command
   def initialize
-    super 'environment', 'Display information about the RubyGems environment'
+    super "environment", "Display information about the RubyGems environment"
   end
 
   def arguments # :nodoc:
@@ -16,7 +16,7 @@ class Gem::Commands::EnvironmentCommand < Gem::Command
           platform        display the supported gem platforms
           <omitted>       display everything
     EOF
-    return args.gsub(/^\s+/, '')
+    return args.gsub(/^\s+/, "")
   end
 
   def description # :nodoc:
@@ -141,7 +141,7 @@ lib/rubygems/defaults/operating_system.rb
 
     out << "  - GEM CONFIGURATION:\n"
     Gem.configuration.each do |name, value|
-      value = value.gsub(/./, '*') if name == 'gemcutter_key'
+      value = value.gsub(/./, "*") if name == "gemcutter_key"
       out << "     - #{name.inspect} => #{value.inspect}\n"
     end
 
@@ -152,7 +152,7 @@ lib/rubygems/defaults/operating_system.rb
 
     out << "  - SHELL PATH:\n"
 
-    shell_path = ENV['PATH'].split(File::PATH_SEPARATOR)
+    shell_path = ENV["PATH"].split(File::PATH_SEPARATOR)
     add_path out, shell_path
 
     out
diff --git a/lib/rubygems/commands/fetch_command.rb b/lib/rubygems/commands/fetch_command.rb
index c8ecb0d48c..582563ba81 100644
--- a/lib/rubygems/commands/fetch_command.rb
+++ b/lib/rubygems/commands/fetch_command.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../local_remote_options'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../version_option"
 
 class Gem::Commands::FetchCommand < Gem::Command
   include Gem::LocalRemoteOptions
@@ -13,7 +13,7 @@ class Gem::Commands::FetchCommand < Gem::Command
       :version           => Gem::Requirement.default,
     }
 
-    super 'fetch', 'Download a gem and place it in the current directory', defaults
+    super "fetch", "Download a gem and place it in the current directory", defaults
 
     add_bulk_threshold_option
     add_proxy_option
@@ -24,13 +24,13 @@ class Gem::Commands::FetchCommand < Gem::Command
     add_platform_option
     add_prerelease_option
 
-    add_option '--[no-]suggestions', 'Suggest alternates when gems are not found' do |value, options|
+    add_option "--[no-]suggestions", "Suggest alternates when gems are not found" do |value, options|
       options[:suggest_alternate] = value
     end
   end
 
   def arguments # :nodoc:
-    'GEMNAME       name of gem to download'
+    "GEMNAME       name of gem to download"
   end
 
   def defaults_str # :nodoc:
diff --git a/lib/rubygems/commands/generate_index_command.rb b/lib/rubygems/commands/generate_index_command.rb
index 87200dab91..8bb24c9ce3 100644
--- a/lib/rubygems/commands/generate_index_command.rb
+++ b/lib/rubygems/commands/generate_index_command.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../indexer'
+require_relative "../command"
+require_relative "../indexer"
 
 ##
 # Generates a index files for use as a gem server.
@@ -9,27 +9,27 @@ require_relative '../indexer'
 
 class Gem::Commands::GenerateIndexCommand < Gem::Command
   def initialize
-    super 'generate_index',
-          'Generates the index files for a gem server directory',
-          :directory => '.', :build_modern => true
+    super "generate_index",
+          "Generates the index files for a gem server directory",
+          :directory => ".", :build_modern => true
 
-    add_option '-d', '--directory=DIRNAME',
-               'repository base dir containing gems subdir' do |dir, options|
+    add_option "-d", "--directory=DIRNAME",
+               "repository base dir containing gems subdir" do |dir, options|
       options[:directory] = File.expand_path dir
     end
 
-    add_option '--[no-]modern',
-               'Generate indexes for RubyGems',
-               '(always true)' do |value, options|
+    add_option "--[no-]modern",
+               "Generate indexes for RubyGems",
+               "(always true)" do |value, options|
       options[:build_modern] = value
     end
 
-    deprecate_option('--modern', version: '4.0', extra_msg: 'Modern indexes (specs, latest_specs, and prerelease_specs) are always generated, so this option is not needed.')
-    deprecate_option('--no-modern', version: '4.0', extra_msg: 'The `--no-modern` option is currently ignored. Modern indexes (specs, latest_specs, and prerelease_specs) are always generated.')
+    deprecate_option("--modern", version: "4.0", extra_msg: "Modern indexes (specs, latest_specs, and prerelease_specs) are always generated, so this option is not needed.")
+    deprecate_option("--no-modern", version: "4.0", extra_msg: "The `--no-modern` option is currently ignored. Modern indexes (specs, latest_specs, and prerelease_specs) are always generated.")
 
-    add_option '--update',
-               'Update modern indexes with gems added',
-               'since the last update' do |value, options|
+    add_option "--update",
+               "Update modern indexes with gems added",
+               "since the last update" do |value, options|
       options[:update] = value
     end
   end
diff --git a/lib/rubygems/commands/help_command.rb b/lib/rubygems/commands/help_command.rb
index 7f3383c9f3..8bfb4458ff 100644
--- a/lib/rubygems/commands/help_command.rb
+++ b/lib/rubygems/commands/help_command.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 class Gem::Commands::HelpCommand < Gem::Command
   # :stopdoc:
@@ -280,7 +280,7 @@ platform.
   # :startdoc:
 
   def initialize
-    super 'help', "Provide help on the 'gem' command"
+    super "help", "Provide help on the 'gem' command"
 
     @command_manager = Gem::CommandManager.instance
   end
@@ -326,7 +326,7 @@ platform.
     desc_width = @command_manager.command_names.map {|n| n.size }.max + 4
 
     summary_width = 80 - margin_width - desc_width
-    wrap_indent = ' ' * (margin_width + desc_width)
+    wrap_indent = " " * (margin_width + desc_width)
     format = "#{' ' * margin_width}%-#{desc_width}s%s"
 
     @command_manager.command_names.each do |cmd_name|
diff --git a/lib/rubygems/commands/info_command.rb b/lib/rubygems/commands/info_command.rb
index 3f2dd4ae0b..ced7751ff5 100644
--- a/lib/rubygems/commands/info_command.rb
+++ b/lib/rubygems/commands/info_command.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require_relative '../command'
-require_relative '../query_utils'
+require_relative "../command"
+require_relative "../query_utils"
 
 class Gem::Commands::InfoCommand < Gem::Command
   include Gem::QueryUtils
@@ -13,7 +13,7 @@ class Gem::Commands::InfoCommand < Gem::Command
 
     add_query_options
 
-    remove_option('-d')
+    remove_option("-d")
 
     defaults[:details] = true
     defaults[:exact] = true
diff --git a/lib/rubygems/commands/install_command.rb b/lib/rubygems/commands/install_command.rb
index 87563accb0..690f90c2e4 100644
--- a/lib/rubygems/commands/install_command.rb
+++ b/lib/rubygems/commands/install_command.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../install_update_options'
-require_relative '../dependency_installer'
-require_relative '../local_remote_options'
-require_relative '../validator'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../install_update_options"
+require_relative "../dependency_installer"
+require_relative "../local_remote_options"
+require_relative "../validator"
+require_relative "../version_option"
 
 ##
 # Gem installer command line tool
@@ -29,7 +29,7 @@ class Gem::Commands::InstallCommand < Gem::Command
 
     defaults.merge!(install_update_options)
 
-    super 'install', 'Install a gem into the local repository', defaults
+    super "install", "Install a gem into the local repository", defaults
 
     add_install_update_options
     add_local_remote_options
@@ -157,7 +157,7 @@ You can use `i` command instead of `install`.
 
     @installed_specs = []
 
-    ENV.delete 'GEM_PATH' if options[:install_dir].nil?
+    ENV.delete "GEM_PATH" if options[:install_dir].nil?
 
     check_install_dir
     check_version
@@ -172,7 +172,7 @@ You can use `i` command instead of `install`.
   end
 
   def install_from_gemdeps # :nodoc:
-    require_relative '../request_set'
+    require_relative "../request_set"
     rs = Gem::RequestSet.new
 
     specs = rs.install_from_gemdeps options do |req, inst|
@@ -247,11 +247,11 @@ You can use `i` command instead of `install`.
 
   def load_hooks # :nodoc:
     if options[:install_as_default]
-      require_relative '../install_default_message'
+      require_relative "../install_default_message"
     else
-      require_relative '../install_message'
+      require_relative "../install_message"
     end
-    require_relative '../rdoc'
+    require_relative "../rdoc"
   end
 
   def show_install_errors(errors) # :nodoc:
@@ -270,7 +270,7 @@ You can use `i` command instead of `install`.
   def show_installed # :nodoc:
     return if @installed_specs.empty?
 
-    gems = @installed_specs.length == 1 ? 'gem' : 'gems'
+    gems = @installed_specs.length == 1 ? "gem" : "gems"
     say "#{@installed_specs.length} #{gems} installed"
   end
 end
diff --git a/lib/rubygems/commands/list_command.rb b/lib/rubygems/commands/list_command.rb
index 010d968f9c..011873b99c 100644
--- a/lib/rubygems/commands/list_command.rb
+++ b/lib/rubygems/commands/list_command.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../query_utils'
+require_relative "../command"
+require_relative "../query_utils"
 
 ##
 # Searches for gems starting with the supplied argument.
@@ -9,7 +9,7 @@ class Gem::Commands::ListCommand < Gem::Command
   include Gem::QueryUtils
 
   def initialize
-    super 'list', 'Display local gems whose name matches REGEXP',
+    super "list", "Display local gems whose name matches REGEXP",
          :domain => :local, :details => false, :versions => true,
          :installed => nil, :version => Gem::Requirement.default
 
diff --git a/lib/rubygems/commands/lock_command.rb b/lib/rubygems/commands/lock_command.rb
index cb6229a2cb..da636492c9 100644
--- a/lib/rubygems/commands/lock_command.rb
+++ b/lib/rubygems/commands/lock_command.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 class Gem::Commands::LockCommand < Gem::Command
   def initialize
-    super 'lock', 'Generate a lockdown list of gems',
+    super "lock", "Generate a lockdown list of gems",
           :strict => false
 
-    add_option '-s', '--[no-]strict',
-               'fail if unable to satisfy a dependency' do |strict, options|
+    add_option "-s", "--[no-]strict",
+               "fail if unable to satisfy a dependency" do |strict, options|
       options[:strict] = strict
     end
   end
diff --git a/lib/rubygems/commands/mirror_command.rb b/lib/rubygems/commands/mirror_command.rb
index 7daa47e2f0..b633cd3d81 100644
--- a/lib/rubygems/commands/mirror_command.rb
+++ b/lib/rubygems/commands/mirror_command.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 unless defined? Gem::Commands::MirrorCommand
   class Gem::Commands::MirrorCommand < Gem::Command
     def initialize
-      super('mirror', 'Mirror all gem files (requires rubygems-mirror)')
+      super("mirror", "Mirror all gem files (requires rubygems-mirror)")
       begin
-        Gem::Specification.find_by_name('rubygems-mirror').activate
+        Gem::Specification.find_by_name("rubygems-mirror").activate
       rescue Gem::LoadError
         # no-op
       end
diff --git a/lib/rubygems/commands/open_command.rb b/lib/rubygems/commands/open_command.rb
index 1e616fd68f..d5283f72dd 100644
--- a/lib/rubygems/commands/open_command.rb
+++ b/lib/rubygems/commands/open_command.rb
@@ -1,18 +1,18 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../version_option"
 
 class Gem::Commands::OpenCommand < Gem::Command
   include Gem::VersionOption
 
   def initialize
-    super 'open', 'Open gem sources in editor'
+    super "open", "Open gem sources in editor"
 
-    add_option('-e', '--editor COMMAND', String,
+    add_option("-e", "--editor COMMAND", String,
                "Prepends COMMAND to gem path. Could be used to specify editor.") do |command, options|
       options[:editor] = command || get_env_editor
     end
-    add_option('-v', '--version VERSION', String,
+    add_option("-v", "--version VERSION", String,
                "Opens specific gem version") do |version|
       options[:version] = version
     end
@@ -40,10 +40,10 @@ class Gem::Commands::OpenCommand < Gem::Command
   end
 
   def get_env_editor
-    ENV['GEM_EDITOR'] ||
-      ENV['VISUAL'] ||
-      ENV['EDITOR'] ||
-      'vi'
+    ENV["GEM_EDITOR"] ||
+      ENV["VISUAL"] ||
+      ENV["EDITOR"] ||
+      "vi"
   end
 
   def execute
diff --git a/lib/rubygems/commands/outdated_command.rb b/lib/rubygems/commands/outdated_command.rb
index 162d338320..1785194389 100644
--- a/lib/rubygems/commands/outdated_command.rb
+++ b/lib/rubygems/commands/outdated_command.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../local_remote_options'
-require_relative '../spec_fetcher'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../spec_fetcher"
+require_relative "../version_option"
 
 class Gem::Commands::OutdatedCommand < Gem::Command
   include Gem::LocalRemoteOptions
   include Gem::VersionOption
 
   def initialize
-    super 'outdated', 'Display all gems that need updates'
+    super "outdated", "Display all gems that need updates"
 
     add_local_remote_options
     add_platform_option
diff --git a/lib/rubygems/commands/owner_command.rb b/lib/rubygems/commands/owner_command.rb
index 42b0d79135..4a0f7aa3e4 100644
--- a/lib/rubygems/commands/owner_command.rb
+++ b/lib/rubygems/commands/owner_command.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../local_remote_options'
-require_relative '../gemcutter_utilities'
-require_relative '../text'
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../gemcutter_utilities"
+require_relative "../text"
 
 class Gem::Commands::OwnerCommand < Gem::Command
   include Gem::Text
@@ -34,23 +34,23 @@ permission to.
   end
 
   def initialize
-    super 'owner', 'Manage gem owners of a gem on the push server'
+    super "owner", "Manage gem owners of a gem on the push server"
     add_proxy_option
     add_key_option
     add_otp_option
     defaults.merge! :add => [], :remove => []
 
-    add_option '-a', '--add NEW_OWNER', 'Add an owner by user identifier' do |value, options|
+    add_option "-a", "--add NEW_OWNER", "Add an owner by user identifier" do |value, options|
       options[:add] << value
     end
 
-    add_option '-r', '--remove OLD_OWNER', 'Remove an owner by user identifier' do |value, options|
+    add_option "-r", "--remove OLD_OWNER", "Remove an owner by user identifier" do |value, options|
       options[:remove] << value
     end
 
-    add_option '-h', '--host HOST',
-               'Use another gemcutter-compatible host',
-               '  (e.g. https://rubygems.org)' do |value, options|
+    add_option "-h", "--host HOST",
+               "Use another gemcutter-compatible host",
+               "  (e.g. https://rubygems.org)" do |value, options|
       options[:host] = value
     end
   end
@@ -108,7 +108,7 @@ permission to.
 
   def send_owner_request(method, name, owner)
     rubygems_api_request method, "api/v1/gems/#{name}/owners", scope: get_owner_scope(method: method) do |request|
-      request.set_form_data 'email' => owner
+      request.set_form_data "email" => owner
       request.add_field "Authorization", api_key
     end
   end
diff --git a/lib/rubygems/commands/pristine_command.rb b/lib/rubygems/commands/pristine_command.rb
index 030c1bffce..d4dadf0736 100644
--- a/lib/rubygems/commands/pristine_command.rb
+++ b/lib/rubygems/commands/pristine_command.rb
@@ -1,67 +1,67 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../package'
-require_relative '../installer'
-require_relative '../version_option'
+require_relative "../command"
+require_relative "../package"
+require_relative "../installer"
+require_relative "../version_option"
 
 class Gem::Commands::PristineCommand < Gem::Command
   include Gem::VersionOption
 
   def initialize
-    super 'pristine',
-          'Restores installed gems to pristine condition from files located in the gem cache',
+    super "pristine",
+          "Restores installed gems to pristine condition from files located in the gem cache",
           :version => Gem::Requirement.default,
           :extensions => true,
           :extensions_set => false,
           :all => false
 
-    add_option('--all',
-               'Restore all installed gems to pristine',
-               'condition') do |value, options|
+    add_option("--all",
+               "Restore all installed gems to pristine",
+               "condition") do |value, options|
       options[:all] = value
     end
 
-    add_option('--skip=gem_name',
-               'used on --all, skip if name == gem_name') do |value, options|
+    add_option("--skip=gem_name",
+               "used on --all, skip if name == gem_name") do |value, options|
       options[:skip] ||= []
       options[:skip] << value
     end
 
-    add_option('--[no-]extensions',
-               'Restore gems with extensions',
-               'in addition to regular gems') do |value, options|
+    add_option("--[no-]extensions",
+               "Restore gems with extensions",
+               "in addition to regular gems") do |value, options|
       options[:extensions_set] = true
       options[:extensions]     = value
     end
 
-    add_option('--only-executables',
-               'Only restore executables') do |value, options|
+    add_option("--only-executables",
+               "Only restore executables") do |value, options|
       options[:only_executables] = value
     end
 
-    add_option('--only-plugins',
-               'Only restore plugins') do |value, options|
+    add_option("--only-plugins",
+               "Only restore plugins") do |value, options|
       options[:only_plugins] = value
     end
 
-    add_option('-E', '--[no-]env-shebang',
-               'Rewrite executables with a shebang',
-               'of /usr/bin/env') do |value, options|
+    add_option("-E", "--[no-]env-shebang",
+               "Rewrite executables with a shebang",
+               "of /usr/bin/env") do |value, options|
       options[:env_shebang] = value
     end
 
-    add_option('-i', '--install-dir DIR',
-               'Gem repository to get binstubs and plugins installed') do |value, options|
+    add_option("-i", "--install-dir DIR",
+               "Gem repository to get binstubs and plugins installed") do |value, options|
       options[:install_dir] = File.expand_path(value)
     end
 
-    add_option('-n', '--bindir DIR',
-               'Directory where executables are',
-               'located') do |value, options|
+    add_option("-n", "--bindir DIR",
+               "Directory where executables are",
+               "located") do |value, options|
       options[:bin_dir] = File.expand_path(value)
     end
 
-    add_version_option('restore to', 'pristine condition')
+    add_version_option("restore to", "pristine condition")
   end
 
   def arguments # :nodoc:
@@ -69,7 +69,7 @@ class Gem::Commands::PristineCommand < Gem::Command
   end
 
   def defaults_str # :nodoc:
-    '--extensions'
+    "--extensions"
   end
 
   def description # :nodoc:
@@ -143,7 +143,7 @@ extensions will be restored.
       gem = spec.cache_file
 
       unless File.exist? gem or options[:only_executables] or options[:only_plugins]
-        require_relative '../remote_fetcher'
+        require_relative "../remote_fetcher"
 
         say "Cached gem for #{spec.full_name} not found, attempting to fetch..."
 
@@ -163,8 +163,8 @@ extensions will be restored.
         if options.include? :env_shebang
           options[:env_shebang]
         else
-          install_defaults = Gem::ConfigFile::PLATFORM_DEFAULTS['install']
-          install_defaults.to_s['--env-shebang']
+          install_defaults = Gem::ConfigFile::PLATFORM_DEFAULTS["install"]
+          install_defaults.to_s["--env-shebang"]
         end
 
       bin_dir = options[:bin_dir] if options[:bin_dir]
diff --git a/lib/rubygems/commands/push_command.rb b/lib/rubygems/commands/push_command.rb
index 4d0d5a9f4b..46b65f4e15 100644
--- a/lib/rubygems/commands/push_command.rb
+++ b/lib/rubygems/commands/push_command.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../local_remote_options'
-require_relative '../gemcutter_utilities'
-require_relative '../package'
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../gemcutter_utilities"
+require_relative "../package"
 
 class Gem::Commands::PushCommand < Gem::Command
   include Gem::LocalRemoteOptions
@@ -29,7 +29,7 @@ The push command will use ~/.gem/credentials to authenticate to a server, but yo
   end
 
   def initialize
-    super 'push', 'Push a gem up to the gem server', :host => self.host
+    super "push", "Push a gem up to the gem server", :host => self.host
 
     @user_defined_host = false
 
@@ -37,9 +37,9 @@ The push command will use ~/.gem/credentials to authenticate to a server, but yo
     add_key_option
     add_otp_option
 
-    add_option('--host HOST',
-               'Push to another gemcutter-compatible host',
-               '  (e.g. https://rubygems.org)') do |value, options|
+    add_option("--host HOST",
+               "Push to another gemcutter-compatible host",
+               "  (e.g. https://rubygems.org)") do |value, options|
       options[:host] = value
       @user_defined_host = true
     end
diff --git a/lib/rubygems/commands/query_command.rb b/lib/rubygems/commands/query_command.rb
index 442c4b19bb..c6315acf8c 100644
--- a/lib/rubygems/commands/query_command.rb
+++ b/lib/rubygems/commands/query_command.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../query_utils'
-require_relative '../deprecate'
+require_relative "../command"
+require_relative "../query_utils"
+require_relative "../deprecate"
 
 class Gem::Commands::QueryCommand < Gem::Command
   extend Gem::Deprecate
@@ -17,15 +17,15 @@ class Gem::Commands::QueryCommand < Gem::Command
     alert_warning message unless Gem::Deprecate.skip
   end
 
-  def initialize(name = 'query',
-                 summary = 'Query gem information in local or remote repositories')
+  def initialize(name = "query",
+                 summary = "Query gem information in local or remote repositories")
     super name, summary,
          :domain => :local, :details => false, :versions => true,
          :installed => nil, :version => Gem::Requirement.default
 
-    add_option('-n', '--name-matches REGEXP',
-               'Name of gem(s) to query on matches the',
-               'provided REGEXP') do |value, options|
+    add_option("-n", "--name-matches REGEXP",
+               "Name of gem(s) to query on matches the",
+               "provided REGEXP") do |value, options|
       options[:name] = /#{value}/i
     end
 
diff --git a/lib/rubygems/commands/rdoc_command.rb b/lib/rubygems/commands/rdoc_command.rb
index 7c5d6212f5..17ad6f836b 100644
--- a/lib/rubygems/commands/rdoc_command.rb
+++ b/lib/rubygems/commands/rdoc_command.rb
@@ -1,35 +1,35 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../version_option'
-require_relative '../rdoc'
-require 'fileutils'
+require_relative "../command"
+require_relative "../version_option"
+require_relative "../rdoc"
+require "fileutils"
 
 class Gem::Commands::RdocCommand < Gem::Command
   include Gem::VersionOption
 
   def initialize
-    super 'rdoc', 'Generates RDoc for pre-installed gems',
+    super "rdoc", "Generates RDoc for pre-installed gems",
           :version => Gem::Requirement.default,
           :include_rdoc => false, :include_ri => true, :overwrite => false
 
-    add_option('--all',
-               'Generate RDoc/RI documentation for all',
-               'installed gems') do |value, options|
+    add_option("--all",
+               "Generate RDoc/RI documentation for all",
+               "installed gems") do |value, options|
       options[:all] = value
     end
 
-    add_option('--[no-]rdoc',
-               'Generate RDoc HTML') do |value, options|
+    add_option("--[no-]rdoc",
+               "Generate RDoc HTML") do |value, options|
       options[:include_rdoc] = value
     end
 
-    add_option('--[no-]ri',
-               'Generate RI data') do |value, options|
+    add_option("--[no-]ri",
+               "Generate RI data") do |value, options|
       options[:include_ri] = value
     end
 
-    add_option('--[no-]overwrite',
-               'Overwrite installed documents') do |value, options|
+    add_option("--[no-]overwrite",
+               "Overwrite installed documents") do |value, options|
       options[:overwrite] = value
     end
 
@@ -69,7 +69,7 @@ Use --overwrite to force rebuilding of documentation.
     end
 
     if specs.empty?
-      alert_error 'No matching gems found'
+      alert_error "No matching gems found"
       terminate_interaction 1
     end
 
@@ -79,8 +79,8 @@ Use --overwrite to force rebuilding of documentation.
       doc.force = options[:overwrite]
 
       if options[:overwrite]
-        FileUtils.rm_rf File.join(spec.doc_dir, 'ri')
-        FileUtils.rm_rf File.join(spec.doc_dir, 'rdoc')
+        FileUtils.rm_rf File.join(spec.doc_dir, "ri")
+        FileUtils.rm_rf File.join(spec.doc_dir, "rdoc")
       end
 
       begin
diff --git a/lib/rubygems/commands/search_command.rb b/lib/rubygems/commands/search_command.rb
index 75d99986f9..3f8f7e13f2 100644
--- a/lib/rubygems/commands/search_command.rb
+++ b/lib/rubygems/commands/search_command.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../query_utils'
+require_relative "../command"
+require_relative "../query_utils"
 
 class Gem::Commands::SearchCommand < Gem::Command
   include Gem::QueryUtils
 
   def initialize
-    super 'search', 'Display remote gems whose name matches REGEXP',
+    super "search", "Display remote gems whose name matches REGEXP",
          :domain => :remote, :details => false, :versions => true,
          :installed => nil, :version => Gem::Requirement.default
 
diff --git a/lib/rubygems/commands/server_command.rb b/lib/rubygems/commands/server_command.rb
index f8cad3b5db..56be07c79d 100644
--- a/lib/rubygems/commands/server_command.rb
+++ b/lib/rubygems/commands/server_command.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 unless defined? Gem::Commands::ServerCommand
   class Gem::Commands::ServerCommand < Gem::Command
     def initialize
-      super('server', 'Starts up a web server that hosts the RDoc (requires rubygems-server)')
+      super("server", "Starts up a web server that hosts the RDoc (requires rubygems-server)")
       begin
-        Gem::Specification.find_by_name('rubygems-server').activate
+        Gem::Specification.find_by_name("rubygems-server").activate
       rescue Gem::LoadError
         # no-op
       end
diff --git a/lib/rubygems/commands/setup_command.rb b/lib/rubygems/commands/setup_command.rb
index db2fefa65e..1ed889a713 100644
--- a/lib/rubygems/commands/setup_command.rb
+++ b/lib/rubygems/commands/setup_command.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 ##
 # Installs RubyGems itself.  This command is ordinarily only available from a
@@ -12,47 +12,47 @@ class Gem::Commands::SetupCommand < Gem::Command
   ENV_PATHS = %w[/usr/bin/env /bin/env].freeze
 
   def initialize
-    super 'setup', 'Install RubyGems',
+    super "setup", "Install RubyGems",
           :format_executable => false, :document => %w[ri],
           :force => true,
-          :site_or_vendor => 'sitelibdir',
-          :destdir => '', :prefix => '', :previous_version => '',
+          :site_or_vendor => "sitelibdir",
+          :destdir => "", :prefix => "", :previous_version => "",
           :regenerate_binstubs => true,
           :regenerate_plugins => true
 
-    add_option '--previous-version=VERSION',
-               'Previous version of RubyGems',
-               'Used for changelog processing' do |version, options|
+    add_option "--previous-version=VERSION",
+               "Previous version of RubyGems",
+               "Used for changelog processing" do |version, options|
       options[:previous_version] = version
     end
 
-    add_option '--prefix=PREFIX',
-               'Prefix path for installing RubyGems',
-               'Will not affect gem repository location' do |prefix, options|
+    add_option "--prefix=PREFIX",
+               "Prefix path for installing RubyGems",
+               "Will not affect gem repository location" do |prefix, options|
       options[:prefix] = File.expand_path prefix
     end
 
-    add_option '--destdir=DESTDIR',
-               'Root directory to install RubyGems into',
-               'Mainly used for packaging RubyGems' do |destdir, options|
+    add_option "--destdir=DESTDIR",
+               "Root directory to install RubyGems into",
+               "Mainly used for packaging RubyGems" do |destdir, options|
       options[:destdir] = File.expand_path destdir
     end
 
-    add_option '--[no-]vendor',
-               'Install into vendorlibdir not sitelibdir' do |vendor, options|
-      options[:site_or_vendor] = vendor ? 'vendorlibdir' : 'sitelibdir'
+    add_option "--[no-]vendor",
+               "Install into vendorlibdir not sitelibdir" do |vendor, options|
+      options[:site_or_vendor] = vendor ? "vendorlibdir" : "sitelibdir"
     end
 
-    add_option '--[no-]format-executable',
-               'Makes `gem` match ruby',
-               'If Ruby is ruby18, gem will be gem18' do |value, options|
+    add_option "--[no-]format-executable",
+               "Makes `gem` match ruby",
+               "If Ruby is ruby18, gem will be gem18" do |value, options|
       options[:format_executable] = value
     end
 
-    add_option '--[no-]document [TYPES]', Array,
-               'Generate documentation for RubyGems',
-               'List the documentation types you wish to',
-               'generate.  For example: rdoc,ri' do |value, options|
+    add_option "--[no-]document [TYPES]", Array,
+               "Generate documentation for RubyGems",
+               "List the documentation types you wish to",
+               "generate.  For example: rdoc,ri" do |value, options|
       options[:document] = case value
       when nil   then %w[rdoc ri]
       when false then []
@@ -60,46 +60,46 @@ class Gem::Commands::SetupCommand < Gem::Command
       end
     end
 
-    add_option '--[no-]rdoc',
-               'Generate RDoc documentation for RubyGems' do |value, options|
+    add_option "--[no-]rdoc",
+               "Generate RDoc documentation for RubyGems" do |value, options|
       if value
-        options[:document] << 'rdoc'
+        options[:document] << "rdoc"
       else
-        options[:document].delete 'rdoc'
+        options[:document].delete "rdoc"
       end
 
       options[:document].uniq!
     end
 
-    add_option '--[no-]ri',
-               'Generate RI documentation for RubyGems' do |value, options|
+    add_option "--[no-]ri",
+               "Generate RI documentation for RubyGems" do |value, options|
       if value
-        options[:document] << 'ri'
+        options[:document] << "ri"
       else
-        options[:document].delete 'ri'
+        options[:document].delete "ri"
       end
 
       options[:document].uniq!
     end
 
-    add_option '--[no-]regenerate-binstubs',
-               'Regenerate gem binstubs' do |value, options|
+    add_option "--[no-]regenerate-binstubs",
+               "Regenerate gem binstubs" do |value, options|
       options[:regenerate_binstubs] = value
     end
 
-    add_option '--[no-]regenerate-plugins',
-               'Regenerate gem plugins' do |value, options|
+    add_option "--[no-]regenerate-plugins",
+               "Regenerate gem plugins" do |value, options|
       options[:regenerate_plugins] = value
     end
 
-    add_option '-f', '--[no-]force',
-               'Forcefully overwrite binstubs' do |value, options|
+    add_option "-f", "--[no-]force",
+               "Forcefully overwrite binstubs" do |value, options|
       options[:force] = value
     end
 
-    add_option('-E', '--[no-]env-shebang',
-               'Rewrite executables with a shebang',
-               'of /usr/bin/env') do |value, options|
+    add_option("-E", "--[no-]env-shebang",
+               "Rewrite executables with a shebang",
+               "of /usr/bin/env") do |value, options|
       options[:env_shebang] = value
     end
 
@@ -107,7 +107,7 @@ class Gem::Commands::SetupCommand < Gem::Command
   end
 
   def check_ruby_version
-    required_version = Gem::Requirement.new '>= 2.3.0'
+    required_version = Gem::Requirement.new ">= 2.3.0"
 
     unless required_version.satisfied_by? Gem.ruby_version
       alert_error "Expected Ruby version #{required_version}, is #{Gem.ruby_version}"
@@ -149,7 +149,7 @@ By default, this RubyGems will install gem as:
 
     check_ruby_version
 
-    require 'fileutils'
+    require "fileutils"
     if Gem.configuration.really_verbose
       extend FileUtils::Verbose
     else
@@ -194,7 +194,7 @@ By default, this RubyGems will install gem as:
     end
 
     if options[:previous_version].empty?
-      options[:previous_version] = Gem::VERSION.sub(/[0-9]+$/, '0')
+      options[:previous_version] = Gem::VERSION.sub(/[0-9]+$/, "0")
     end
 
     options[:previous_version] = Gem::Version.new(options[:previous_version])
@@ -216,7 +216,7 @@ By default, this RubyGems will install gem as:
     end
 
     if documentation_success
-      if options[:document].include? 'rdoc'
+      if options[:document].include? "rdoc"
         say "Rdoc documentation was installed. You may now invoke:"
         say "  gem server"
         say "and then peruse beautifully formatted documentation for your gems"
@@ -227,7 +227,7 @@ By default, this RubyGems will install gem as:
         say
       end
 
-      if options[:document].include? 'ri'
+      if options[:document].include? "ri"
         say "Ruby Interactive (ri) documentation was installed. ri is kind of like man "
         say "pages for Ruby libraries. You may access it like this:"
         say "  ri Classname"
@@ -244,14 +244,14 @@ By default, this RubyGems will install gem as:
   def install_executables(bin_dir)
     prog_mode = options[:prog_mode] || 0755
 
-    executables = { 'gem' => 'bin' }
+    executables = { "gem" => "bin" }
     executables.each do |tool, path|
       say "Installing #{tool} executable" if @verbose
 
       Dir.chdir path do
         bin_file = "gem"
 
-        require 'tmpdir'
+        require "tmpdir"
 
         dest_file = target_bin_path(bin_dir, bin_file)
         bin_tmp_file = File.join Dir.tmpdir, "#{bin_file}.#{$$}"
@@ -260,7 +260,7 @@ By default, this RubyGems will install gem as:
           bin = File.readlines bin_file
           bin[0] = shebang
 
-          File.open bin_tmp_file, 'w' do |fp|
+          File.open bin_tmp_file, "w" do |fp|
             fp.puts bin.join
           end
 
@@ -275,7 +275,7 @@ By default, this RubyGems will install gem as:
         begin
           bin_cmd_file = File.join Dir.tmpdir, "#{bin_file}.bat"
 
-          File.open bin_cmd_file, 'w' do |file|
+          File.open bin_cmd_file, "w" do |file|
             file.puts <<-TEXT
   @ECHO OFF
   IF NOT "%~f0" == "~f0" GOTO :WinNT
@@ -296,7 +296,7 @@ By default, this RubyGems will install gem as:
 
   def shebang
     if options[:env_shebang]
-      ruby_name = RbConfig::CONFIG['ruby_install_name']
+      ruby_name = RbConfig::CONFIG["ruby_install_name"]
       @env_path ||= ENV_PATHS.find {|env_path| File.executable? env_path }
       "#!#{@env_path} #{ruby_name}\n"
     else
@@ -305,8 +305,8 @@ By default, this RubyGems will install gem as:
   end
 
   def install_lib(lib_dir)
-    libs = { 'RubyGems' => 'lib' }
-    libs['Bundler'] = 'bundler/lib'
+    libs = { "RubyGems" => "lib" }
+    libs["Bundler"] = "bundler/lib"
     libs.each do |tool, path|
       say "Installing #{tool}" if @verbose
 
@@ -319,7 +319,7 @@ By default, this RubyGems will install gem as:
   end
 
   def install_rdoc
-    gem_doc_dir = File.join Gem.dir, 'doc'
+    gem_doc_dir = File.join Gem.dir, "doc"
     rubygems_name = "rubygems-#{Gem::VERSION}"
     rubygems_doc_dir = File.join gem_doc_dir, rubygems_name
 
@@ -333,19 +333,19 @@ By default, this RubyGems will install gem as:
        (not File.exist? rubygems_doc_dir or
         File.writable? rubygems_doc_dir)
       say "Removing old RubyGems RDoc and ri" if @verbose
-      Dir[File.join(Gem.dir, 'doc', 'rubygems-[0-9]*')].each do |dir|
+      Dir[File.join(Gem.dir, "doc", "rubygems-[0-9]*")].each do |dir|
         rm_rf dir
       end
 
-      require_relative '../rdoc'
+      require_relative "../rdoc"
 
-      fake_spec = Gem::Specification.new 'rubygems', Gem::VERSION
+      fake_spec = Gem::Specification.new "rubygems", Gem::VERSION
       def fake_spec.full_gem_path
-        File.expand_path '../../..', __dir__
+        File.expand_path "../../..", __dir__
       end
 
-      generate_ri   = options[:document].include? 'ri'
-      generate_rdoc = options[:document].include? 'rdoc'
+      generate_ri   = options[:document].include? "ri"
+      generate_rdoc = options[:document].include? "rdoc"
 
       rdoc = Gem::RDoc.new fake_spec, generate_rdoc, generate_ri
       rdoc.generate
@@ -397,7 +397,7 @@ By default, this RubyGems will install gem as:
       cp File.join("bundler", bundler_spec.bindir, e), File.join(bundler_bin_dir, e)
     end
 
-    require_relative '../installer'
+    require_relative "../installer"
 
     Dir.chdir("bundler") do
       built_gem = Gem::Package.build(bundler_spec)
@@ -439,10 +439,10 @@ By default, this RubyGems will install gem as:
     prefix = options[:prefix]
 
     if prefix.empty?
-      man_dir = RbConfig::CONFIG['mandir']
+      man_dir = RbConfig::CONFIG["mandir"]
       return unless man_dir
     else
-      man_dir = File.join prefix, 'man'
+      man_dir = File.join prefix, "man"
     end
 
     prepend_destdir_if_present(man_dir)
@@ -454,10 +454,10 @@ By default, this RubyGems will install gem as:
 
     if prefix.empty?
       lib_dir = RbConfig::CONFIG[site_or_vendor]
-      bin_dir = RbConfig::CONFIG['bindir']
+      bin_dir = RbConfig::CONFIG["bindir"]
     else
-      lib_dir = File.join prefix, 'lib'
-      bin_dir = File.join prefix, 'bin'
+      lib_dir = File.join prefix, "lib"
+      bin_dir = File.join prefix, "bin"
     end
 
     [prepend_destdir_if_present(lib_dir), prepend_destdir_if_present(bin_dir)]
@@ -465,19 +465,19 @@ By default, this RubyGems will install gem as:
 
   def files_in(dir)
     Dir.chdir dir do
-      Dir.glob(File.join('**', '*'), File::FNM_DOTMATCH).
+      Dir.glob(File.join("**", "*"), File::FNM_DOTMATCH).
         select {|f| !File.directory?(f) }
     end
   end
 
   def remove_old_bin_files(bin_dir)
     old_bin_files = {
-      'gem_mirror' => 'gem mirror',
-      'gem_server' => 'gem server',
-      'gemlock' => 'gem lock',
-      'gemri' => 'ri',
-      'gemwhich' => 'gem which',
-      'index_gem_repository.rb' => 'gem generate_index',
+      "gem_mirror" => "gem mirror",
+      "gem_server" => "gem server",
+      "gemlock" => "gem lock",
+      "gemri" => "ri",
+      "gemwhich" => "gem which",
+      "index_gem_repository.rb" => "gem generate_index",
     }
 
     old_bin_files.each do |old_bin_file, new_name|
@@ -486,7 +486,7 @@ By default, this RubyGems will install gem as:
 
       deprecation_message = "`#{old_bin_file}` has been deprecated. Use `#{new_name}` instead."
 
-      File.open old_bin_path, 'w' do |fp|
+      File.open old_bin_path, "w" do |fp|
         fp.write <<-EOF
 #!#{Gem.ruby}
 
@@ -496,15 +496,15 @@ abort "#{deprecation_message}"
 
       next unless Gem.win_platform?
 
-      File.open "#{old_bin_path}.bat", 'w' do |fp|
+      File.open "#{old_bin_path}.bat", "w" do |fp|
         fp.puts %(@ECHO.#{deprecation_message})
       end
     end
   end
 
   def remove_old_lib_files(lib_dir)
-    lib_dirs = { File.join(lib_dir, 'rubygems') => 'lib/rubygems' }
-    lib_dirs[File.join(lib_dir, 'bundler')] = 'bundler/lib/bundler'
+    lib_dirs = { File.join(lib_dir, "rubygems") => "lib/rubygems" }
+    lib_dirs[File.join(lib_dir, "bundler")] = "bundler/lib/bundler"
     lib_dirs.each do |old_lib_dir, new_lib_dir|
       lib_files = files_in(new_lib_dir)
 
@@ -512,11 +512,11 @@ abort "#{deprecation_message}"
 
       to_remove = old_lib_files - lib_files
 
-      gauntlet_rubygems = File.join(lib_dir, 'gauntlet_rubygems.rb')
+      gauntlet_rubygems = File.join(lib_dir, "gauntlet_rubygems.rb")
       to_remove << gauntlet_rubygems if File.exist? gauntlet_rubygems
 
       to_remove.delete_if do |file|
-        file.start_with? 'defaults'
+        file.start_with? "defaults"
       end
 
       remove_file_list(to_remove, old_lib_dir)
@@ -542,7 +542,7 @@ abort "#{deprecation_message}"
   end
 
   def show_release_notes
-    release_notes = File.join Dir.pwd, 'CHANGELOG.md'
+    release_notes = File.join Dir.pwd, "CHANGELOG.md"
 
     release_notes =
       if File.exist? release_notes
@@ -573,10 +573,10 @@ abort "#{deprecation_message}"
   end
 
   def uninstall_old_gemcutter
-    require_relative '../uninstaller'
+    require_relative "../uninstaller"
 
-    ui = Gem::Uninstaller.new('gemcutter', :all => true, :ignore => true,
-                              :version => '< 0.4')
+    ui = Gem::Uninstaller.new("gemcutter", :all => true, :ignore => true,
+                              :version => "< 0.4")
     ui.uninstall
   rescue Gem::InstallError
   end
@@ -625,7 +625,7 @@ abort "#{deprecation_message}"
     destdir = options[:destdir]
     return path if destdir.empty?
 
-    File.join(options[:destdir], path.gsub(/^[a-zA-Z]:/, ''))
+    File.join(options[:destdir], path.gsub(/^[a-zA-Z]:/, ""))
   end
 
   def install_file_list(files, dest_dir)
diff --git a/lib/rubygems/commands/signin_command.rb b/lib/rubygems/commands/signin_command.rb
index 23bb2f937f..2660eee4f3 100644
--- a/lib/rubygems/commands/signin_command.rb
+++ b/lib/rubygems/commands/signin_command.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../gemcutter_utilities'
+require_relative "../command"
+require_relative "../gemcutter_utilities"
 
 class Gem::Commands::SigninCommand < Gem::Command
   include Gem::GemcutterUtilities
 
   def initialize
-    super 'signin', 'Sign in to any gemcutter-compatible host. '\
-          'It defaults to https://rubygems.org'
+    super "signin", "Sign in to any gemcutter-compatible host. "\
+          "It defaults to https://rubygems.org"
 
-    add_option('--host HOST', 'Push to another gemcutter-compatible host') do |value, options|
+    add_option("--host HOST", "Push to another gemcutter-compatible host") do |value, options|
       options[:host] = value
     end
 
@@ -17,10 +17,10 @@ class Gem::Commands::SigninCommand < Gem::Command
   end
 
   def description # :nodoc:
-    'The signin command executes host sign in for a push server (the default is'\
-    ' https://rubygems.org). The host can be provided with the host flag or can'\
-    ' be inferred from the provided gem. Host resolution matches the resolution'\
-    ' strategy for the push command.'
+    "The signin command executes host sign in for a push server (the default is"\
+    " https://rubygems.org). The host can be provided with the host flag or can"\
+    " be inferred from the provided gem. Host resolution matches the resolution"\
+    " strategy for the push command."
   end
 
   def usage # :nodoc:
diff --git a/lib/rubygems/commands/signout_command.rb b/lib/rubygems/commands/signout_command.rb
index c9485e0c1b..fa688ea3f8 100644
--- a/lib/rubygems/commands/signout_command.rb
+++ b/lib/rubygems/commands/signout_command.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 class Gem::Commands::SignoutCommand < Gem::Command
   def initialize
-    super 'signout', 'Sign out from all the current sessions.'
+    super "signout", "Sign out from all the current sessions."
   end
 
   def description # :nodoc:
-    'The `signout` command is used to sign out from all current sessions,'\
-    ' allowing you to sign in using a different set of credentials.'
+    "The `signout` command is used to sign out from all current sessions,"\
+    " allowing you to sign in using a different set of credentials."
   end
 
   def usage # :nodoc:
@@ -19,13 +19,13 @@ class Gem::Commands::SignoutCommand < Gem::Command
     credentials_path = Gem.configuration.credentials_path
 
     if !File.exist?(credentials_path)
-      alert_error 'You are not currently signed in.'
+      alert_error "You are not currently signed in."
     elsif !File.writable?(credentials_path)
       alert_error "File '#{Gem.configuration.credentials_path}' is read-only."\
-                  ' Please make sure it is writable.'
+                  " Please make sure it is writable."
     else
       Gem.configuration.unset_api_key!
-      say 'You have successfully signed out from all sessions.'
+      say "You have successfully signed out from all sessions."
     end
   end
 end
diff --git a/lib/rubygems/commands/sources_command.rb b/lib/rubygems/commands/sources_command.rb
index 884d9445c9..a5f2d022c6 100644
--- a/lib/rubygems/commands/sources_command.rb
+++ b/lib/rubygems/commands/sources_command.rb
@@ -1,40 +1,40 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../remote_fetcher'
-require_relative '../spec_fetcher'
-require_relative '../local_remote_options'
+require_relative "../command"
+require_relative "../remote_fetcher"
+require_relative "../spec_fetcher"
+require_relative "../local_remote_options"
 
 class Gem::Commands::SourcesCommand < Gem::Command
   include Gem::LocalRemoteOptions
 
   def initialize
-    require 'fileutils'
+    require "fileutils"
 
-    super 'sources',
-          'Manage the sources and cache file RubyGems uses to search for gems'
+    super "sources",
+          "Manage the sources and cache file RubyGems uses to search for gems"
 
-    add_option '-a', '--add SOURCE_URI', 'Add source' do |value, options|
+    add_option "-a", "--add SOURCE_URI", "Add source" do |value, options|
       options[:add] = value
     end
 
-    add_option '-l', '--list', 'List sources' do |value, options|
+    add_option "-l", "--list", "List sources" do |value, options|
       options[:list] = value
     end
 
-    add_option '-r', '--remove SOURCE_URI', 'Remove source' do |value, options|
+    add_option "-r", "--remove SOURCE_URI", "Remove source" do |value, options|
       options[:remove] = value
     end
 
-    add_option '-c', '--clear-all',
-               'Remove all sources (clear the cache)' do |value, options|
+    add_option "-c", "--clear-all",
+               "Remove all sources (clear the cache)" do |value, options|
       options[:clear_all] = value
     end
 
-    add_option '-u', '--update', 'Update source cache' do |value, options|
+    add_option "-u", "--update", "Update source cache" do |value, options|
       options[:update] = value
     end
 
-    add_option '-f', '--[no-]force', "Do not show any confirmation prompts and behave as if 'yes' was always answered" do |value, options|
+    add_option "-f", "--[no-]force", "Do not show any confirmation prompts and behave as if 'yes' was always answered" do |value, options|
       options[:force] = value
     end
 
@@ -82,8 +82,8 @@ Do you want to add this source?
   def check_rubygems_https(source_uri) # :nodoc:
     uri = URI source_uri
 
-    if uri.scheme and uri.scheme.downcase == 'http' and
-       uri.host.downcase == 'rubygems.org'
+    if uri.scheme and uri.scheme.downcase == "http" and
+       uri.host.downcase == "rubygems.org"
       question = <<-QUESTION.chomp
 https://rubygems.org is recommended for security over #{uri}
 
@@ -112,7 +112,7 @@ Do you want to add this insecure source?
   end
 
   def defaults_str # :nodoc:
-    '--list'
+    "--list"
   end
 
   def description # :nodoc:
diff --git a/lib/rubygems/commands/specification_command.rb b/lib/rubygems/commands/specification_command.rb
index 6fba3a36ec..6457a755ae 100644
--- a/lib/rubygems/commands/specification_command.rb
+++ b/lib/rubygems/commands/specification_command.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../local_remote_options'
-require_relative '../version_option'
-require_relative '../package'
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../version_option"
+require_relative "../package"
 
 class Gem::Commands::SpecificationCommand < Gem::Command
   include Gem::LocalRemoteOptions
@@ -11,28 +11,28 @@ class Gem::Commands::SpecificationCommand < Gem::Command
   def initialize
     Gem.load_yaml
 
-    super 'specification', 'Display gem specification (in yaml)',
+    super "specification", "Display gem specification (in yaml)",
           :domain => :local, :version => Gem::Requirement.default,
           :format => :yaml
 
-    add_version_option('examine')
+    add_version_option("examine")
     add_platform_option
     add_prerelease_option
 
-    add_option('--all', 'Output specifications for all versions of',
-               'the gem') do |value, options|
+    add_option("--all", "Output specifications for all versions of",
+               "the gem") do |value, options|
       options[:all] = true
     end
 
-    add_option('--ruby', 'Output ruby format') do |value, options|
+    add_option("--ruby", "Output ruby format") do |value, options|
       options[:format] = :ruby
     end
 
-    add_option('--yaml', 'Output YAML format') do |value, options|
+    add_option("--yaml", "Output YAML format") do |value, options|
       options[:format] = :yaml
     end
 
-    add_option('--marshal', 'Output Marshal format') do |value, options|
+    add_option("--marshal", "Output Marshal format") do |value, options|
       options[:format] = :marshal
     end
 
diff --git a/lib/rubygems/commands/stale_command.rb b/lib/rubygems/commands/stale_command.rb
index 62a97966f1..0246f42e3e 100644
--- a/lib/rubygems/commands/stale_command.rb
+++ b/lib/rubygems/commands/stale_command.rb
@@ -1,9 +1,9 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 class Gem::Commands::StaleCommand < Gem::Command
   def initialize
-    super('stale', 'List gems along with access times')
+    super("stale", "List gems along with access times")
   end
 
   def description # :nodoc:
diff --git a/lib/rubygems/commands/uninstall_command.rb b/lib/rubygems/commands/uninstall_command.rb
index 467c8bf7ed..d03a96bf87 100644
--- a/lib/rubygems/commands/uninstall_command.rb
+++ b/lib/rubygems/commands/uninstall_command.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../version_option'
-require_relative '../uninstaller'
-require 'fileutils'
+require_relative "../command"
+require_relative "../version_option"
+require_relative "../uninstaller"
+require "fileutils"
 
 ##
 # Gem uninstaller command line tool
@@ -13,78 +13,78 @@ class Gem::Commands::UninstallCommand < Gem::Command
   include Gem::VersionOption
 
   def initialize
-    super 'uninstall', 'Uninstall gems from the local repository',
+    super "uninstall", "Uninstall gems from the local repository",
           :version => Gem::Requirement.default, :user_install => true,
           :check_dev => false, :vendor => false
 
-    add_option('-a', '--[no-]all',
-      'Uninstall all matching versions'
+    add_option("-a", "--[no-]all",
+      "Uninstall all matching versions"
     ) do |value, options|
       options[:all] = value
     end
 
-    add_option('-I', '--[no-]ignore-dependencies',
-               'Ignore dependency requirements while',
-               'uninstalling') do |value, options|
+    add_option("-I", "--[no-]ignore-dependencies",
+               "Ignore dependency requirements while",
+               "uninstalling") do |value, options|
       options[:ignore] = value
     end
 
-    add_option('-D', '--[no-]check-development',
-               'Check development dependencies while uninstalling',
-               '(default: false)') do |value, options|
+    add_option("-D", "--[no-]check-development",
+               "Check development dependencies while uninstalling",
+               "(default: false)") do |value, options|
       options[:check_dev] = value
     end
 
-    add_option('-x', '--[no-]executables',
-                 'Uninstall applicable executables without',
-                 'confirmation') do |value, options|
+    add_option("-x", "--[no-]executables",
+                 "Uninstall applicable executables without",
+                 "confirmation") do |value, options|
       options[:executables] = value
     end
 
-    add_option('-i', '--install-dir DIR',
-               'Directory to uninstall gem from') do |value, options|
+    add_option("-i", "--install-dir DIR",
+               "Directory to uninstall gem from") do |value, options|
       options[:install_dir] = File.expand_path(value)
     end
 
-    add_option('-n', '--bindir DIR',
-               'Directory to remove executables from') do |value, options|
+    add_option("-n", "--bindir DIR",
+               "Directory to remove executables from") do |value, options|
       options[:bin_dir] = File.expand_path(value)
     end
 
-    add_option('--[no-]user-install',
-               'Uninstall from user\'s home directory',
-               'in addition to GEM_HOME.') do |value, options|
+    add_option("--[no-]user-install",
+               "Uninstall from user's home directory",
+               "in addition to GEM_HOME.") do |value, options|
       options[:user_install] = value
     end
 
-    add_option('--[no-]format-executable',
-               'Assume executable names match Ruby\'s prefix and suffix.') do |value, options|
+    add_option("--[no-]format-executable",
+               "Assume executable names match Ruby's prefix and suffix.") do |value, options|
       options[:format_executable] = value
     end
 
-    add_option('--[no-]force',
-               'Uninstall all versions of the named gems',
-               'ignoring dependencies') do |value, options|
+    add_option("--[no-]force",
+               "Uninstall all versions of the named gems",
+               "ignoring dependencies") do |value, options|
       options[:force] = value
     end
 
-    add_option('--[no-]abort-on-dependent',
-               'Prevent uninstalling gems that are',
-               'depended on by other gems.') do |value, options|
+    add_option("--[no-]abort-on-dependent",
+               "Prevent uninstalling gems that are",
+               "depended on by other gems.") do |value, options|
       options[:abort_on_dependent] = value
     end
 
     add_version_option
     add_platform_option
 
-    add_option('--vendor',
-               'Uninstall gem from the vendor directory.',
-               'Only for use by gem repackagers.') do |value, options|
+    add_option("--vendor",
+               "Uninstall gem from the vendor directory.",
+               "Only for use by gem repackagers.") do |value, options|
       unless Gem.vendor_dir
-        raise Gem::OptionParser::InvalidOption.new 'your platform is not supported'
+        raise Gem::OptionParser::InvalidOption.new "your platform is not supported"
       end
 
-      alert_warning 'Use your OS package manager to uninstall vendor gems'
+      alert_warning "Use your OS package manager to uninstall vendor gems"
       options[:vendor] = true
       options[:install_dir] = Gem.vendor_dir
     end
diff --git a/lib/rubygems/commands/unpack_command.rb b/lib/rubygems/commands/unpack_command.rb
index 3f1708375f..a365e85416 100644
--- a/lib/rubygems/commands/unpack_command.rb
+++ b/lib/rubygems/commands/unpack_command.rb
@@ -1,9 +1,9 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../version_option'
-require_relative '../security_option'
-require_relative '../remote_fetcher'
-require_relative '../package'
+require_relative "../command"
+require_relative "../version_option"
+require_relative "../security_option"
+require_relative "../remote_fetcher"
+require_relative "../package"
 
 # forward-declare
 
@@ -17,18 +17,18 @@ class Gem::Commands::UnpackCommand < Gem::Command
   include Gem::SecurityOption
 
   def initialize
-    require 'fileutils'
+    require "fileutils"
 
-    super 'unpack', 'Unpack an installed gem to the current directory',
+    super "unpack", "Unpack an installed gem to the current directory",
           :version => Gem::Requirement.default,
           :target  => Dir.pwd
 
-    add_option('--target=DIR',
-               'target directory for unpacking') do |value, options|
+    add_option("--target=DIR",
+               "target directory for unpacking") do |value, options|
       options[:target] = value
     end
 
-    add_option('--spec', 'unpack the gem specification') do |value, options|
+    add_option("--spec", "unpack the gem specification") do |value, options|
       options[:spec] = true
     end
 
@@ -103,11 +103,11 @@ command help for an example.
           end
         end
 
-        File.open destination, 'w' do |io|
+        File.open destination, "w" do |io|
           io.write metadata
         end
       else
-        basename = File.basename path, '.gem'
+        basename = File.basename path, ".gem"
         target_dir = File.expand_path basename, options[:target]
 
         package = Gem::Package.new path, security_policy
diff --git a/lib/rubygems/commands/update_command.rb b/lib/rubygems/commands/update_command.rb
index 04ce0ea935..a079642669 100644
--- a/lib/rubygems/commands/update_command.rb
+++ b/lib/rubygems/commands/update_command.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../command_manager'
-require_relative '../dependency_installer'
-require_relative '../install_update_options'
-require_relative '../local_remote_options'
-require_relative '../spec_fetcher'
-require_relative '../version_option'
-require_relative '../install_message' # must come before rdoc for messaging
-require_relative '../rdoc'
+require_relative "../command"
+require_relative "../command_manager"
+require_relative "../dependency_installer"
+require_relative "../install_update_options"
+require_relative "../local_remote_options"
+require_relative "../spec_fetcher"
+require_relative "../version_option"
+require_relative "../install_message" # must come before rdoc for messaging
+require_relative "../rdoc"
 
 class Gem::Commands::UpdateCommand < Gem::Command
   include Gem::InstallUpdateOptions
@@ -25,7 +25,7 @@ class Gem::Commands::UpdateCommand < Gem::Command
 
     options.merge!(install_update_options)
 
-    super 'update', 'Update installed gems to the latest version', options
+    super "update", "Update installed gems to the latest version", options
 
     add_install_update_options
 
@@ -35,8 +35,8 @@ class Gem::Commands::UpdateCommand < Gem::Command
       value
     end
 
-    add_option('--system [VERSION]', Gem::Version,
-               'Update the RubyGems system software') do |value, options|
+    add_option("--system [VERSION]", Gem::Version,
+               "Update the RubyGems system software") do |value, options|
       value = true unless value
 
       options[:system] = value
@@ -176,13 +176,13 @@ command to remove old versions.
     args = update_rubygems_arguments
     version = spec.version
 
-    update_dir = File.join spec.base_dir, 'gems', "rubygems-update-#{version}"
+    update_dir = File.join spec.base_dir, "gems", "rubygems-update-#{version}"
 
     Dir.chdir update_dir do
       say "Installing RubyGems #{version}" unless options[:silent]
 
       installed = preparing_gem_layout_for(version) do
-        system Gem.ruby, '--disable-gems', 'setup.rb', *args
+        system Gem.ruby, "--disable-gems", "setup.rb", *args
       end
 
       say "RubyGems system software updated" if installed unless options[:silent]
@@ -224,7 +224,7 @@ command to remove old versions.
     requirement = Gem::Requirement.new ">= #{Gem::VERSION}"
 
     rubygems_update         = Gem::Specification.new
-    rubygems_update.name    = 'rubygems-update'
+    rubygems_update.name    = "rubygems-update"
     rubygems_update.version = version
 
     highest_remote_tup = highest_remote_name_tuple(rubygems_update)
@@ -278,8 +278,8 @@ command to remove old versions.
 
     check_oldest_rubygems version
 
-    installed_gems = Gem::Specification.find_all_by_name 'rubygems-update', requirement
-    installed_gems = update_gem('rubygems-update', version) if installed_gems.empty? || installed_gems.first.version != version
+    installed_gems = Gem::Specification.find_all_by_name "rubygems-update", requirement
+    installed_gems = update_gem("rubygems-update", version) if installed_gems.empty? || installed_gems.first.version != version
     return if installed_gems.empty?
 
     install_rubygems installed_gems.first
@@ -287,11 +287,11 @@ command to remove old versions.
 
   def update_rubygems_arguments # :nodoc:
     args = []
-    args << '--silent' if options[:silent]
-    args << '--prefix' << Gem.prefix if Gem.prefix
-    args << '--no-document' unless options[:document].include?('rdoc') || options[:document].include?('ri')
-    args << '--no-format-executable' if options[:no_format_executable]
-    args << '--previous-version' << Gem::VERSION if
+    args << "--silent" if options[:silent]
+    args << "--prefix" << Gem.prefix if Gem.prefix
+    args << "--no-document" unless options[:document].include?("rdoc") || options[:document].include?("ri")
+    args << "--no-format-executable" if options[:no_format_executable]
+    args << "--previous-version" << Gem::VERSION if
       options[:system] == true or
         Gem::Version.new(options[:system]) >= Gem::Version.new(2)
     args
diff --git a/lib/rubygems/commands/which_command.rb b/lib/rubygems/commands/which_command.rb
index 44e87a2b98..78493e9380 100644
--- a/lib/rubygems/commands/which_command.rb
+++ b/lib/rubygems/commands/which_command.rb
@@ -1,17 +1,17 @@
 # frozen_string_literal: true
-require_relative '../command'
+require_relative "../command"
 
 class Gem::Commands::WhichCommand < Gem::Command
   def initialize
-    super 'which', 'Find the location of a library file you can require',
+    super "which", "Find the location of a library file you can require",
           :search_gems_first => false, :show_all => false
 
-    add_option '-a', '--[no-]all', 'show all matching files' do |show_all, options|
+    add_option "-a", "--[no-]all", "show all matching files" do |show_all, options|
       options[:show_all] = show_all
     end
 
-    add_option '-g', '--[no-]gems-first',
-               'search gems before non-gems' do |gems_first, options|
+    add_option "-g", "--[no-]gems-first",
+               "search gems before non-gems" do |gems_first, options|
       options[:search_gems_first] = gems_first
     end
   end
@@ -39,7 +39,7 @@ requiring to see why it does not behave as you expect.
     found = true
 
     options[:args].each do |arg|
-      arg = arg.sub(/#{Regexp.union(*Gem.suffixes)}$/, '')
+      arg = arg.sub(/#{Regexp.union(*Gem.suffixes)}$/, "")
       dirs = $LOAD_PATH
 
       spec = Gem::Specification.find_by_path arg
diff --git a/lib/rubygems/commands/yank_command.rb b/lib/rubygems/commands/yank_command.rb
index cad78aec5f..1499f72f5d 100644
--- a/lib/rubygems/commands/yank_command.rb
+++ b/lib/rubygems/commands/yank_command.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
-require_relative '../command'
-require_relative '../local_remote_options'
-require_relative '../version_option'
-require_relative '../gemcutter_utilities'
+require_relative "../command"
+require_relative "../local_remote_options"
+require_relative "../version_option"
+require_relative "../gemcutter_utilities"
 
 class Gem::Commands::YankCommand < Gem::Command
   include Gem::LocalRemoteOptions
@@ -28,15 +28,15 @@ data you will need to change them immediately and yank your gem.
   end
 
   def initialize
-    super 'yank', 'Remove a pushed gem from the index'
+    super "yank", "Remove a pushed gem from the index"
 
     add_version_option("remove")
     add_platform_option("remove")
     add_otp_option
 
-    add_option('--host HOST',
-               'Yank from another gemcutter-compatible host',
-               '  (e.g. https://rubygems.org)') do |value, options|
+    add_option("--host HOST",
+               "Yank from another gemcutter-compatible host",
+               "  (e.g. https://rubygems.org)") do |value, options|
       options[:host] = value
     end
 
@@ -76,10 +76,10 @@ data you will need to change them immediately and yank your gem.
       request.add_field("Authorization", api_key)
 
       data = {
-        'gem_name' => name,
-        'version' => version,
+        "gem_name" => name,
+        "version" => version,
       }
-      data['platform'] = platform if platform
+      data["platform"] = platform if platform
 
       request.set_form_data data
     end
diff --git a/lib/rubygems/config_file.rb b/lib/rubygems/config_file.rb
index 5dd2bfe88d..d711a51bd0 100644
--- a/lib/rubygems/config_file.rb
+++ b/lib/rubygems/config_file.rb
@@ -5,8 +5,8 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'user_interaction'
-require 'rbconfig'
+require_relative "user_interaction"
+require "rbconfig"
 
 ##
 # Gem::ConfigFile RubyGems options and gem command options from gemrc.
@@ -71,7 +71,7 @@ class Gem::ConfigFile
 
   # :startdoc:
 
-  SYSTEM_WIDE_CONFIG_FILE = File.join SYSTEM_CONFIG_PATH, 'gemrc'
+  SYSTEM_WIDE_CONFIG_FILE = File.join SYSTEM_CONFIG_PATH, "gemrc"
 
   ##
   # List of arguments supplied to the config file object.
@@ -182,20 +182,20 @@ class Gem::ConfigFile
     @update_sources = DEFAULT_UPDATE_SOURCES
     @concurrent_downloads = DEFAULT_CONCURRENT_DOWNLOADS
     @cert_expiration_length_days = DEFAULT_CERT_EXPIRATION_LENGTH_DAYS
-    @ipv4_fallback_enabled = ENV['IPV4_FALLBACK_ENABLED'] == 'true' || DEFAULT_IPV4_FALLBACK_ENABLED
+    @ipv4_fallback_enabled = ENV["IPV4_FALLBACK_ENABLED"] == "true" || DEFAULT_IPV4_FALLBACK_ENABLED
 
     operating_system_config = Marshal.load Marshal.dump(OPERATING_SYSTEM_DEFAULTS)
     platform_config = Marshal.load Marshal.dump(PLATFORM_DEFAULTS)
     system_config = load_file SYSTEM_WIDE_CONFIG_FILE
     user_config = load_file config_file_name.dup.tap(&Gem::UNTAINT)
 
-    environment_config = (ENV['GEMRC'] || '')
+    environment_config = (ENV["GEMRC"] || "")
       .split(File::PATH_SEPARATOR).inject({}) do |result, file|
         result.merge load_file file
       end
 
     @hash = operating_system_config.merge platform_config
-    unless args.index '--norc'
+    unless args.index "--norc"
       @hash = @hash.merge system_config
       @hash = @hash.merge user_config
       @hash = @hash.merge environment_config
@@ -269,7 +269,7 @@ if you believe they were disclosed to a third party.
   # Location of RubyGems.org credentials
 
   def credentials_path
-    credentials = File.join Gem.user_home, '.gem', 'credentials'
+    credentials = File.join Gem.user_home, ".gem", "credentials"
     if File.exist? credentials
       credentials
     else
@@ -320,13 +320,13 @@ if you believe they were disclosed to a third party.
     config = load_file(credentials_path).merge(host => api_key)
 
     dirname = File.dirname credentials_path
-    require 'fileutils'
+    require "fileutils"
     FileUtils.mkdir_p(dirname)
 
     Gem.load_yaml
 
     permissions = 0600 & (~File.umask)
-    File.open(credentials_path, 'w', permissions) do |f|
+    File.open(credentials_path, "w", permissions) do |f|
       f.write config.to_yaml
     end
 
@@ -389,7 +389,7 @@ if you believe they were disclosed to a third party.
     yield :backtrace, @backtrace
     yield :bulk_threshold, @bulk_threshold
 
-    yield 'config_file_name', @config_file_name if @config_file_name
+    yield "config_file_name", @config_file_name if @config_file_name
 
     hash.each(&block)
   end
@@ -405,7 +405,7 @@ if you believe they were disclosed to a third party.
       when /^--debug$/ then
         $DEBUG = true
 
-        warn 'NOTE:  Debugging mode prints all exceptions even when rescued'
+        warn "NOTE:  Debugging mode prints all exceptions even when rescued"
       else
         @args << arg
       end
@@ -444,7 +444,7 @@ if you believe they were disclosed to a third party.
       @hash[:ssl_client_cert] if @hash.key? :ssl_client_cert
 
     keys = yaml_hash.keys.map {|key| key.to_s }
-    keys << 'debug'
+    keys << "debug"
     re = Regexp.union(*keys)
 
     @hash.each do |key, value|
@@ -458,10 +458,10 @@ if you believe they were disclosed to a third party.
 
   # Writes out this config file, replacing its source.
   def write
-    require 'fileutils'
+    require "fileutils"
     FileUtils.mkdir_p File.dirname(config_file_name)
 
-    File.open config_file_name, 'w' do |io|
+    File.open config_file_name, "w" do |io|
       io.write to_yaml
     end
   end
diff --git a/lib/rubygems/core_ext/kernel_gem.rb b/lib/rubygems/core_ext/kernel_gem.rb
index e722225739..6f96cab84f 100644
--- a/lib/rubygems/core_ext/kernel_gem.rb
+++ b/lib/rubygems/core_ext/kernel_gem.rb
@@ -39,7 +39,7 @@ module Kernel
   #   GEM_SKIP=libA:libB ruby -I../libA -I../libB ./mycode.rb
 
   def gem(gem_name, *requirements) # :doc:
-    skip_list = (ENV['GEM_SKIP'] || "").split(/:/)
+    skip_list = (ENV["GEM_SKIP"] || "").split(/:/)
     raise Gem::LoadError, "skipping #{gem_name}" if skip_list.include? gem_name
 
     if gem_name.kind_of? Gem::Dependency
diff --git a/lib/rubygems/core_ext/kernel_require.rb b/lib/rubygems/core_ext/kernel_require.rb
index 23badd75d2..8064d813e1 100644
--- a/lib/rubygems/core_ext/kernel_require.rb
+++ b/lib/rubygems/core_ext/kernel_require.rb
@@ -5,7 +5,7 @@
 # See LICENSE.txt for permissions.
 #++
 
-require 'monitor'
+require "monitor"
 
 module Kernel
 
diff --git a/lib/rubygems/core_ext/kernel_warn.rb b/lib/rubygems/core_ext/kernel_warn.rb
index 3373cfdd3b..7df6c48b8f 100644
--- a/lib/rubygems/core_ext/kernel_warn.rb
+++ b/lib/rubygems/core_ext/kernel_warn.rb
@@ -39,7 +39,7 @@ if RUBY_VERSION >= "2.5" && !Gem::KERNEL_WARN_IGNORES_INTERNAL_ENTRIES
           start += 1
 
           if path = loc.path
-            unless path.start_with?(rubygems_path) or path.start_with?('<internal:')
+            unless path.start_with?(rubygems_path) or path.start_with?("<internal:")
               # Non-rubygems frames
               uplevel -= 1
             end
diff --git a/lib/rubygems/core_ext/tcpsocket_init.rb b/lib/rubygems/core_ext/tcpsocket_init.rb
index 2a79b63bd6..c9e0a92953 100644
--- a/lib/rubygems/core_ext/tcpsocket_init.rb
+++ b/lib/rubygems/core_ext/tcpsocket_init.rb
@@ -1,4 +1,4 @@
-require 'socket'
+require "socket"
 
 module CoreExtensions
   module TCPSocketExt
diff --git a/lib/rubygems/defaults.rb b/lib/rubygems/defaults.rb
index 39b69ddb1c..d27f286265 100644
--- a/lib/rubygems/defaults.rb
+++ b/lib/rubygems/defaults.rb
@@ -20,10 +20,10 @@ module Gem
   # specified in the environment
 
   def self.default_spec_cache_dir
-    default_spec_cache_dir = File.join Gem.user_home, '.gem', 'specs'
+    default_spec_cache_dir = File.join Gem.user_home, ".gem", "specs"
 
     unless File.exist?(default_spec_cache_dir)
-      default_spec_cache_dir = File.join Gem.data_home, 'gem', 'specs'
+      default_spec_cache_dir = File.join Gem.data_home, "gem", "specs"
     end
 
     default_spec_cache_dir
@@ -34,7 +34,7 @@ module Gem
   # specified in the environment
 
   def self.default_dir
-    @default_dir ||= File.join(RbConfig::CONFIG['rubylibprefix'], 'gems', RbConfig::CONFIG['ruby_version'])
+    @default_dir ||= File.join(RbConfig::CONFIG["rubylibprefix"], "gems", RbConfig::CONFIG["ruby_version"])
   end
 
   ##
@@ -81,7 +81,7 @@ module Gem
     Dir.home.dup
   rescue
     if Gem.win_platform?
-      File.expand_path File.join(ENV['HOMEDRIVE'] || ENV['SystemDrive'], '/')
+      File.expand_path File.join(ENV["HOMEDRIVE"] || ENV["SystemDrive"], "/")
     else
       File.expand_path "/"
     end
@@ -103,7 +103,7 @@ module Gem
     gem_dir = File.join(Gem.user_home, ".gem")
     gem_dir = File.join(Gem.data_home, "gem") unless File.exist?(gem_dir)
     parts = [gem_dir, ruby_engine]
-    parts << RbConfig::CONFIG['ruby_version'] unless RbConfig::CONFIG['ruby_version'].empty?
+    parts << RbConfig::CONFIG["ruby_version"] unless RbConfig::CONFIG["ruby_version"].empty?
     File.join parts
   end
 
@@ -111,14 +111,14 @@ module Gem
   # The path to standard location of the user's configuration directory.
 
   def self.config_home
-    @config_home ||= (ENV["XDG_CONFIG_HOME"] || File.join(Gem.user_home, '.config'))
+    @config_home ||= (ENV["XDG_CONFIG_HOME"] || File.join(Gem.user_home, ".config"))
   end
 
   ##
   # Finds the user's config file
 
   def self.find_config_file
-    gemrc = File.join Gem.user_home, '.gemrc'
+    gemrc = File.join Gem.user_home, ".gemrc"
     if File.exist? gemrc
       gemrc
     else
@@ -137,14 +137,14 @@ module Gem
   # The path to standard location of the user's cache directory.
 
   def self.cache_home
-    @cache_home ||= (ENV["XDG_CACHE_HOME"] || File.join(Gem.user_home, '.cache'))
+    @cache_home ||= (ENV["XDG_CACHE_HOME"] || File.join(Gem.user_home, ".cache"))
   end
 
   ##
   # The path to standard location of the user's data directory.
 
   def self.data_home
-    @data_home ||= (ENV["XDG_DATA_HOME"] || File.join(Gem.user_home, '.local', 'share'))
+    @data_home ||= (ENV["XDG_DATA_HOME"] || File.join(Gem.user_home, ".local", "share"))
   end
 
   ##
@@ -169,7 +169,7 @@ module Gem
   # Deduce Ruby's --program-prefix and --program-suffix from its install name
 
   def self.default_exec_format
-    exec_format = RbConfig::CONFIG['ruby_install_name'].sub('ruby', '%s') rescue '%s'
+    exec_format = RbConfig::CONFIG["ruby_install_name"].sub("ruby", "%s") rescue "%s"
 
     unless exec_format =~ /%s/
       raise Gem::Exception,
@@ -183,7 +183,7 @@ module Gem
   # The default directory for binaries
 
   def self.default_bindir
-    RbConfig::CONFIG['bindir']
+    RbConfig::CONFIG["bindir"]
   end
 
   def self.ruby_engine
@@ -227,14 +227,14 @@ module Gem
   # Directory where vendor gems are installed.
 
   def self.vendor_dir # :nodoc:
-    if vendor_dir = ENV['GEM_VENDOR']
+    if vendor_dir = ENV["GEM_VENDOR"]
       return vendor_dir.dup
     end
 
-    return nil unless RbConfig::CONFIG.key? 'vendordir'
+    return nil unless RbConfig::CONFIG.key? "vendordir"
 
-    File.join RbConfig::CONFIG['vendordir'], 'gems',
-              RbConfig::CONFIG['ruby_version']
+    File.join RbConfig::CONFIG["vendordir"], "gems",
+              RbConfig::CONFIG["ruby_version"]
   end
 
   ##
diff --git a/lib/rubygems/dependency.rb b/lib/rubygems/dependency.rb
index 3640362364..c561db1af2 100644
--- a/lib/rubygems/dependency.rb
+++ b/lib/rubygems/dependency.rb
@@ -97,14 +97,14 @@ class Gem::Dependency
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 1, 'Gem::Dependency.new(', ')' do
+    q.group 1, "Gem::Dependency.new(", ")" do
       q.pp name
-      q.text ','
+      q.text ","
       q.breakable
 
       q.pp requirement
 
-      q.text ','
+      q.text ","
       q.breakable
 
       q.pp type
@@ -197,7 +197,7 @@ class Gem::Dependency
     reqs = other.requirement.requirements
 
     return false unless reqs.length == 1
-    return false unless reqs.first.first == '='
+    return false unless reqs.first.first == "="
 
     version = reqs.first.last
 
diff --git a/lib/rubygems/dependency_installer.rb b/lib/rubygems/dependency_installer.rb
index 913bba32eb..acdad6b98f 100644
--- a/lib/rubygems/dependency_installer.rb
+++ b/lib/rubygems/dependency_installer.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
-require_relative '../rubygems'
-require_relative 'dependency_list'
-require_relative 'package'
-require_relative 'installer'
-require_relative 'spec_fetcher'
-require_relative 'user_interaction'
-require_relative 'available_set'
-require_relative 'deprecate'
+require_relative "../rubygems"
+require_relative "dependency_list"
+require_relative "package"
+require_relative "installer"
+require_relative "spec_fetcher"
+require_relative "user_interaction"
+require_relative "available_set"
+require_relative "deprecate"
 
 ##
 # Installs a gem along with all its dependencies from local and remote gems.
diff --git a/lib/rubygems/dependency_list.rb b/lib/rubygems/dependency_list.rb
index 10e08fc703..3cecb1e536 100644
--- a/lib/rubygems/dependency_list.rb
+++ b/lib/rubygems/dependency_list.rb
@@ -5,8 +5,8 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'tsort'
-require_relative 'deprecate'
+require_relative "tsort"
+require_relative "deprecate"
 
 ##
 # Gem::DependencyList is used for installing and uninstalling gems in the
diff --git a/lib/rubygems/doctor.rb b/lib/rubygems/doctor.rb
index d14c64a166..662eff9559 100644
--- a/lib/rubygems/doctor.rb
+++ b/lib/rubygems/doctor.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
-require_relative '../rubygems'
-require_relative 'user_interaction'
+require_relative "../rubygems"
+require_relative "user_interaction"
 
 ##
 # Cleans up after a partially-failed uninstall or for an invalid
@@ -19,13 +19,13 @@ class Gem::Doctor
   # subdirectory.
 
   REPOSITORY_EXTENSION_MAP = [ # :nodoc:
-    ['specifications', '.gemspec'],
-    ['build_info',     '.info'],
-    ['cache',          '.gem'],
-    ['doc',            ''],
-    ['extensions',     ''],
-    ['gems',           ''],
-    ['plugins',        ''],
+    ["specifications", ".gemspec"],
+    ["build_info",     ".info"],
+    ["cache",          ".gem"],
+    ["doc",            ""],
+    ["extensions",     ""],
+    ["gems",           ""],
+    ["plugins",        ""],
   ].freeze
 
   missing =
@@ -74,8 +74,8 @@ class Gem::Doctor
     Gem.use_paths @gem_repository.to_s
 
     unless gem_repository?
-      say 'This directory does not appear to be a RubyGems repository, ' +
-          'skipping'
+      say "This directory does not appear to be a RubyGems repository, " +
+          "skipping"
       say
       return
     end
@@ -111,16 +111,16 @@ class Gem::Doctor
       basename = File.basename(child, extension)
       next if installed_specs.include? basename
       next if /^rubygems-\d/ =~ basename
-      next if 'specifications' == sub_directory and 'default' == basename
-      next if 'plugins' == sub_directory and Gem.plugin_suffix_regexp =~ basename
+      next if "specifications" == sub_directory and "default" == basename
+      next if "plugins" == sub_directory and Gem.plugin_suffix_regexp =~ basename
 
-      type = File.directory?(child) ? 'directory' : 'file'
+      type = File.directory?(child) ? "directory" : "file"
 
       action = if @dry_run
-        'Extra'
+        "Extra"
       else
         FileUtils.rm_r(child)
-        'Removed'
+        "Removed"
       end
 
       say "#{action} #{type} #{sub_directory}/#{File.basename(child)}"
diff --git a/lib/rubygems/errors.rb b/lib/rubygems/errors.rb
index e6e222033d..ac82a551a5 100644
--- a/lib/rubygems/errors.rb
+++ b/lib/rubygems/errors.rb
@@ -136,8 +136,8 @@ module Gem
       "Found %s (%s), but was for platform%s %s" %
         [@name,
          @version,
-         @platforms.size == 1 ? '' : 's',
-         @platforms.join(' ,')]
+         @platforms.size == 1 ? "" : "s",
+         @platforms.join(" ,")]
     end
   end
 
diff --git a/lib/rubygems/exceptions.rb b/lib/rubygems/exceptions.rb
index 1806869098..5fadbe9bca 100644
--- a/lib/rubygems/exceptions.rb
+++ b/lib/rubygems/exceptions.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require_relative 'deprecate'
-require_relative 'unknown_command_spell_checker'
+require_relative "deprecate"
+require_relative "unknown_command_spell_checker"
 
 ##
 # Base exception class for RubyGems.  All exception raised by RubyGems are a
@@ -27,7 +27,7 @@ class Gem::UnknownCommandError < Gem::Exception
       if DidYouMean.respond_to?(:correct_error)
         DidYouMean.correct_error(Gem::UnknownCommandError, Gem::UnknownCommandSpellChecker)
       else
-        DidYouMean::SPELL_CHECKERS['Gem::UnknownCommandError'] =
+        DidYouMean::SPELL_CHECKERS["Gem::UnknownCommandError"] =
           Gem::UnknownCommandSpellChecker
 
         prepend DidYouMean::Correctable
@@ -154,7 +154,7 @@ class Gem::ImpossibleDependenciesError < Gem::Exception
 
   def build_message # :nodoc:
     requester  = @request.requester
-    requester  = requester ? requester.spec.full_name : 'The user'
+    requester  = requester ? requester.spec.full_name : "The user"
     dependency = @request.dependency
 
     message = "#{requester} requires #{dependency} but it conflicted:\n".dup
diff --git a/lib/rubygems/ext.rb b/lib/rubygems/ext.rb
index 59fd830437..d714985c21 100644
--- a/lib/rubygems/ext.rb
+++ b/lib/rubygems/ext.rb
@@ -10,10 +10,10 @@
 
 module Gem::Ext; end
 
-require_relative 'ext/build_error'
-require_relative 'ext/builder'
-require_relative 'ext/configure_builder'
-require_relative 'ext/ext_conf_builder'
-require_relative 'ext/rake_builder'
-require_relative 'ext/cmake_builder'
-require_relative 'ext/cargo_builder'
+require_relative "ext/build_error"
+require_relative "ext/builder"
+require_relative "ext/configure_builder"
+require_relative "ext/ext_conf_builder"
+require_relative "ext/rake_builder"
+require_relative "ext/cmake_builder"
+require_relative "ext/cargo_builder"
diff --git a/lib/rubygems/ext/build_error.rb b/lib/rubygems/ext/build_error.rb
index 8ef57ed91a..727bc065c2 100644
--- a/lib/rubygems/ext/build_error.rb
+++ b/lib/rubygems/ext/build_error.rb
@@ -2,7 +2,7 @@
 ##
 # Raised when there is an error while building extensions.
 
-require_relative '../exceptions'
+require_relative "../exceptions"
 
 class Gem::Ext::BuildError < Gem::InstallError
 end
diff --git a/lib/rubygems/ext/builder.rb b/lib/rubygems/ext/builder.rb
index 99dd2c162c..c5a03806b9 100644
--- a/lib/rubygems/ext/builder.rb
+++ b/lib/rubygems/ext/builder.rb
@@ -5,7 +5,7 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative '../user_interaction'
+require_relative "../user_interaction"
 
 class Gem::Ext::Builder
   include Gem::UserInteraction
@@ -18,29 +18,29 @@ class Gem::Ext::Builder
   end
 
   def self.make(dest_path, results, make_dir = Dir.pwd, sitedir = nil)
-    unless File.exist? File.join(make_dir, 'Makefile')
-      raise Gem::InstallError, 'Makefile not found'
+    unless File.exist? File.join(make_dir, "Makefile")
+      raise Gem::InstallError, "Makefile not found"
     end
 
     # try to find make program from Ruby configure arguments first
-    RbConfig::CONFIG['configure_args'] =~ /with-make-prog\=(\w+)/
-    make_program_name = ENV['MAKE'] || ENV['make'] || $1
+    RbConfig::CONFIG["configure_args"] =~ /with-make-prog\=(\w+)/
+    make_program_name = ENV["MAKE"] || ENV["make"] || $1
     unless make_program_name
-      make_program_name = (/mswin/ =~ RUBY_PLATFORM) ? 'nmake' : 'make'
+      make_program_name = (/mswin/ =~ RUBY_PLATFORM) ? "nmake" : "make"
     end
     make_program = Shellwords.split(make_program_name)
 
     # The installation of the bundled gems is failed when DESTDIR is empty in mswin platform.
-    destdir = (/\bnmake/i !~ make_program_name || ENV['DESTDIR'] && ENV['DESTDIR'] != "") ? 'DESTDIR=%s' % ENV['DESTDIR'] : ''
+    destdir = (/\bnmake/i !~ make_program_name || ENV["DESTDIR"] && ENV["DESTDIR"] != "") ? "DESTDIR=%s" % ENV["DESTDIR"] : ""
 
     env = [destdir]
 
     if sitedir
-      env << 'sitearchdir=%s' % sitedir
-      env << 'sitelibdir=%s' % sitedir
+      env << "sitearchdir=%s" % sitedir
+      env << "sitelibdir=%s" % sitedir
     end
 
-    ['clean', '', 'install'].each do |target|
+    ["clean", "", "install"].each do |target|
       # Pass DESTDIR via command line to override what's in MAKEFLAGS
       cmd = [
         *make_program,
@@ -50,7 +50,7 @@ class Gem::Ext::Builder
       begin
         run(cmd, results, "make #{target}".rstrip, make_dir)
       rescue Gem::InstallError
-        raise unless target == 'clean' # ignore clean failure
+        raise unless target == "clean" # ignore clean failure
       end
     end
   end
@@ -59,7 +59,7 @@ class Gem::Ext::Builder
     verbose = Gem.configuration.really_verbose
 
     begin
-      rubygems_gemdeps, ENV['RUBYGEMS_GEMDEPS'] = ENV['RUBYGEMS_GEMDEPS'], nil
+      rubygems_gemdeps, ENV["RUBYGEMS_GEMDEPS"] = ENV["RUBYGEMS_GEMDEPS"], nil
       if verbose
         puts("current directory: #{dir}")
         p(command)
@@ -70,7 +70,7 @@ class Gem::Ext::Builder
 
       require "open3"
       # Set $SOURCE_DATE_EPOCH for the subprocess.
-      build_env = { 'SOURCE_DATE_EPOCH' => Gem.source_date_epoch_string }.merge(env)
+      build_env = { "SOURCE_DATE_EPOCH" => Gem.source_date_epoch_string }.merge(env)
       output, status = begin
                          Open3.capture2e(build_env, *command, :chdir => dir)
                        rescue => error
@@ -82,7 +82,7 @@ class Gem::Ext::Builder
         results << output
       end
     ensure
-      ENV['RUBYGEMS_GEMDEPS'] = rubygems_gemdeps
+      ENV["RUBYGEMS_GEMDEPS"] = rubygems_gemdeps
     end
 
     unless status.success?
@@ -212,11 +212,11 @@ EOF
   # Writes +output+ to gem_make.out in the extension install directory.
 
   def write_gem_make_out(output) # :nodoc:
-    destination = File.join @spec.extension_dir, 'gem_make.out'
+    destination = File.join @spec.extension_dir, "gem_make.out"
 
     FileUtils.mkdir_p @spec.extension_dir
 
-    File.open destination, 'wb' do |io|
+    File.open destination, "wb" do |io|
       io.puts output
     end
 
diff --git a/lib/rubygems/ext/cargo_builder.rb b/lib/rubygems/ext/cargo_builder.rb
index 232c0a313d..e33b07a8a2 100644
--- a/lib/rubygems/ext/cargo_builder.rb
+++ b/lib/rubygems/ext/cargo_builder.rb
@@ -29,14 +29,14 @@ class Gem::Ext::CargoBuilder < Gem::Ext::Builder
   def build_crate(dest_path, results, args, cargo_dir)
     env = build_env
     cmd = cargo_command(cargo_dir, dest_path, args)
-    runner.call cmd, results, 'cargo', cargo_dir, env
+    runner.call cmd, results, "cargo", cargo_dir, env
 
     results
   end
 
   def build_env
     build_env = rb_config_env
-    build_env["RUBY_STATIC"] = "true" if ruby_static? && ENV.key?('RUBY_STATIC')
+    build_env["RUBY_STATIC"] = "true" if ruby_static? && ENV.key?("RUBY_STATIC")
     build_env
   end
 
@@ -46,7 +46,7 @@ class Gem::Ext::CargoBuilder < Gem::Ext::Builder
 
     cmd = []
     cmd += [cargo, "rustc"]
-    cmd += ["--target", ENV['CARGO_BUILD_TARGET']] if ENV['CARGO_BUILD_TARGET']
+    cmd += ["--target", ENV["CARGO_BUILD_TARGET"]] if ENV["CARGO_BUILD_TARGET"]
     cmd += ["--target-dir", dest_path]
     cmd += ["--manifest-path", manifest]
     cmd += ["--lib"]
@@ -144,13 +144,13 @@ class Gem::Ext::CargoBuilder < Gem::Ext::Builder
   def cargo_dylib_path(dest_path)
     prefix = so_ext == "dll" ? "" : "lib"
     path_parts = [dest_path]
-    path_parts << ENV['CARGO_BUILD_TARGET'] if ENV['CARGO_BUILD_TARGET']
+    path_parts << ENV["CARGO_BUILD_TARGET"] if ENV["CARGO_BUILD_TARGET"]
     path_parts += [profile_target_directory, "#{prefix}#{cargo_crate_name}.#{so_ext}"]
     File.join(*path_parts)
   end
 
   def cargo_crate_name
-    spec.metadata.fetch('cargo_crate_name', spec.name).tr('-', '_')
+    spec.metadata.fetch("cargo_crate_name", spec.name).tr("-", "_")
   end
 
   def rustc_dynamic_linker_flags(dest_dir)
@@ -297,8 +297,8 @@ class Gem::Ext::CargoBuilder < Gem::Ext::Builder
 
   def profile_target_directory
     case profile
-    when :release then 'release'
-    when :dev     then 'debug'
+    when :release then "release"
+    when :dev     then "debug"
     else          raise "unknown target directory for profile: #{profile}"
     end
   end
diff --git a/lib/rubygems/ext/cmake_builder.rb b/lib/rubygems/ext/cmake_builder.rb
index e47cabef84..b162664784 100644
--- a/lib/rubygems/ext/cmake_builder.rb
+++ b/lib/rubygems/ext/cmake_builder.rb
@@ -2,8 +2,8 @@
 
 class Gem::Ext::CmakeBuilder < Gem::Ext::Builder
   def self.build(extension, dest_path, results, args=[], lib_dir=nil, cmake_dir=Dir.pwd)
-    unless File.exist?(File.join(cmake_dir, 'Makefile'))
-      require_relative '../command'
+    unless File.exist?(File.join(cmake_dir, "Makefile"))
+      require_relative "../command"
       cmd = ["cmake", ".", "-DCMAKE_INSTALL_PREFIX=#{dest_path}", *Gem::Command.build_args]
 
       run cmd, results, class_name, cmake_dir
diff --git a/lib/rubygems/ext/configure_builder.rb b/lib/rubygems/ext/configure_builder.rb
index eb2f9fce61..51106c6370 100644
--- a/lib/rubygems/ext/configure_builder.rb
+++ b/lib/rubygems/ext/configure_builder.rb
@@ -7,7 +7,7 @@
 
 class Gem::Ext::ConfigureBuilder < Gem::Ext::Builder
   def self.build(extension, dest_path, results, args=[], lib_dir=nil, configure_dir=Dir.pwd)
-    unless File.exist?(File.join(configure_dir, 'Makefile'))
+    unless File.exist?(File.join(configure_dir, "Makefile"))
       cmd = ["sh", "./configure", "--prefix=#{dest_path}", *args]
 
       run cmd, results, class_name, configure_dir
diff --git a/lib/rubygems/ext/ext_conf_builder.rb b/lib/rubygems/ext/ext_conf_builder.rb
index 2f0183fe2f..f8920596d5 100644
--- a/lib/rubygems/ext/ext_conf_builder.rb
+++ b/lib/rubygems/ext/ext_conf_builder.rb
@@ -7,8 +7,8 @@
 
 class Gem::Ext::ExtConfBuilder < Gem::Ext::Builder
   def self.build(extension, dest_path, results, args=[], lib_dir=nil, extension_dir=Dir.pwd)
-    require 'fileutils'
-    require 'tempfile'
+    require "fileutils"
+    require "tempfile"
 
     tmp_dest = Dir.mktmpdir(".gem.", extension_dir)
 
@@ -22,16 +22,16 @@ class Gem::Ext::ExtConfBuilder < Gem::Ext::Builder
 
     begin
       require "shellwords"
-      cmd = Gem.ruby.shellsplit << "-I" << File.expand_path('../..', __dir__) << File.basename(extension)
+      cmd = Gem.ruby.shellsplit << "-I" << File.expand_path("../..", __dir__) << File.basename(extension)
       cmd.push(*args)
 
       run(cmd, results, class_name, extension_dir) do |s, r|
-        mkmf_log = File.join(extension_dir, 'mkmf.log')
+        mkmf_log = File.join(extension_dir, "mkmf.log")
         if File.exist? mkmf_log
           unless s.success?
             r << "To see why this extension failed to compile, please check" \
               " the mkmf.log which can be found here:\n"
-            r << "  " + File.join(dest_path, 'mkmf.log') + "\n"
+            r << "  " + File.join(dest_path, "mkmf.log") + "\n"
           end
           FileUtils.mv mkmf_log, dest_path
         end
@@ -67,7 +67,7 @@ class Gem::Ext::ExtConfBuilder < Gem::Ext::Builder
   private
 
   def self.get_relative_path(path, base)
-    path[0..base.length - 1] = '.' if path.start_with?(base)
+    path[0..base.length - 1] = "." if path.start_with?(base)
     path
   end
 end
diff --git a/lib/rubygems/ext/rake_builder.rb b/lib/rubygems/ext/rake_builder.rb
index fed98e741c..9f2e099d40 100644
--- a/lib/rubygems/ext/rake_builder.rb
+++ b/lib/rubygems/ext/rake_builder.rb
@@ -11,16 +11,16 @@ class Gem::Ext::RakeBuilder < Gem::Ext::Builder
       run([Gem.ruby, File.basename(extension), *args], results, class_name, extension_dir)
     end
 
-    rake = ENV['rake']
+    rake = ENV["rake"]
 
     if rake
       require "shellwords"
       rake = rake.shellsplit
     else
       begin
-        rake = [Gem.ruby, "-I#{File.expand_path("../..", __dir__)}", "-rrubygems", Gem.bin_path('rake', 'rake')]
+        rake = [Gem.ruby, "-I#{File.expand_path("../..", __dir__)}", "-rrubygems", Gem.bin_path("rake", "rake")]
       rescue Gem::Exception
-        rake = [Gem.default_exec_format % 'rake']
+        rake = [Gem.default_exec_format % "rake"]
       end
     end
 
diff --git a/lib/rubygems/gem_runner.rb b/lib/rubygems/gem_runner.rb
index b3f925773b..31890a60d7 100644
--- a/lib/rubygems/gem_runner.rb
+++ b/lib/rubygems/gem_runner.rb
@@ -5,9 +5,9 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative '../rubygems'
-require_relative 'command_manager'
-require_relative 'deprecate'
+require_relative "../rubygems"
+require_relative "command_manager"
+require_relative "deprecate"
 
 ##
 # Run an instance of the gem program.
@@ -41,7 +41,7 @@ class Gem::GemRunner
       config_args = Gem.configuration[command_name]
       config_args = case config_args
       when String
-        config_args.split ' '
+        config_args.split " "
       else
         Array(config_args)
       end
@@ -56,7 +56,7 @@ class Gem::GemRunner
   # other arguments in the list.
 
   def extract_build_args(args) # :nodoc:
-    return [] unless offset = args.index('--')
+    return [] unless offset = args.index("--")
 
     build_args = args.slice!(offset...args.length)
 
diff --git a/lib/rubygems/gemcutter_utilities.rb b/lib/rubygems/gemcutter_utilities.rb
index af0d957bc8..1eeb341bb8 100644
--- a/lib/rubygems/gemcutter_utilities.rb
+++ b/lib/rubygems/gemcutter_utilities.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
-require_relative 'remote_fetcher'
-require_relative 'text'
+require_relative "remote_fetcher"
+require_relative "text"
 
 ##
 # Utility methods for using the RubyGems API.
@@ -19,8 +19,8 @@ module Gem::GemcutterUtilities
   # Add the --key option
 
   def add_key_option
-    add_option('-k', '--key KEYNAME', Symbol,
-               'Use the given API key',
+    add_option("-k", "--key KEYNAME", Symbol,
+               "Use the given API key",
                "from #{Gem.configuration.credentials_path}") do |value,options|
       options[:key] = value
     end
@@ -30,9 +30,9 @@ module Gem::GemcutterUtilities
   # Add the --otp option
 
   def add_otp_option
-    add_option('--otp CODE',
-               'Digit code for multifactor authentication',
-               'You can also use the environment variable GEM_HOST_OTP_CODE') do |value, options|
+    add_option("--otp CODE",
+               "Digit code for multifactor authentication",
+               "You can also use the environment variable GEM_HOST_OTP_CODE") do |value, options|
       options[:otp] = value
     end
   end
@@ -69,7 +69,7 @@ module Gem::GemcutterUtilities
 
     @host ||=
       begin
-        env_rubygems_host = ENV['RUBYGEMS_HOST']
+        env_rubygems_host = ENV["RUBYGEMS_HOST"]
         env_rubygems_host = nil if
           env_rubygems_host and env_rubygems_host.empty?
 
@@ -83,7 +83,7 @@ module Gem::GemcutterUtilities
   # If +allowed_push_host+ metadata is present, then it will only allow that host.
 
   def rubygems_api_request(method, path, host = nil, allowed_push_host = nil, scope: nil, &block)
-    require 'net/http'
+    require "net/http"
 
     self.host = host if host
     unless self.host
@@ -118,7 +118,7 @@ module Gem::GemcutterUtilities
   end
 
   def mfa_unauthorized?(response)
-    response.kind_of?(Net::HTTPUnauthorized) && response.body.start_with?('You have enabled multifactor authentication')
+    response.kind_of?(Net::HTTPUnauthorized) && response.body.start_with?("You have enabled multifactor authentication")
   end
 
   def update_scope(scope)
@@ -240,13 +240,13 @@ module Gem::GemcutterUtilities
   end
 
   def ask_otp
-    say 'You have enabled multi-factor authentication. Please enter OTP code.'
-    options[:otp] = ask 'Code: '
+    say "You have enabled multi-factor authentication. Please enter OTP code."
+    options[:otp] = ask "Code: "
   end
 
   def pretty_host(host)
     if default_host?
-      'RubyGems.org'
+      "RubyGems.org"
     else
       host
     end
diff --git a/lib/rubygems/indexer.rb b/lib/rubygems/indexer.rb
index a5a86f4111..2299932f45 100644
--- a/lib/rubygems/indexer.rb
+++ b/lib/rubygems/indexer.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
-require_relative '../rubygems'
-require_relative 'package'
-require 'tmpdir'
+require_relative "../rubygems"
+require_relative "package"
+require "tmpdir"
 
 ##
 # Top level class for building the gem repository index.
@@ -43,28 +43,28 @@ class Gem::Indexer
   # Create an indexer that will index the gems in +directory+.
 
   def initialize(directory, options = {})
-    require 'fileutils'
-    require 'tmpdir'
-    require 'zlib'
+    require "fileutils"
+    require "tmpdir"
+    require "zlib"
 
     options = { :build_modern => true }.merge options
 
     @build_modern = options[:build_modern]
 
     @dest_directory = directory
-    @directory = Dir.mktmpdir 'gem_generate_index'
+    @directory = Dir.mktmpdir "gem_generate_index"
 
     marshal_name = "Marshal.#{Gem.marshal_version}"
 
-    @master_index = File.join @directory, 'yaml'
+    @master_index = File.join @directory, "yaml"
     @marshal_index = File.join @directory, marshal_name
 
-    @quick_dir = File.join @directory, 'quick'
+    @quick_dir = File.join @directory, "quick"
     @quick_marshal_dir = File.join @quick_dir, marshal_name
     @quick_marshal_dir_base = File.join "quick", marshal_name # FIX: UGH
 
-    @quick_index = File.join @quick_dir, 'index'
-    @latest_index = File.join @quick_dir, 'latest_index'
+    @quick_index = File.join @quick_dir, "index"
+    @latest_index = File.join @quick_dir, "latest_index"
 
     @specs_index = File.join @directory, "specs.#{Gem.marshal_version}"
     @latest_specs_index =
@@ -104,7 +104,7 @@ class Gem::Indexer
 
     files = []
 
-    Gem.time 'Generated Marshal quick index gemspecs' do
+    Gem.time "Generated Marshal quick index gemspecs" do
       specs.each do |spec|
         next if spec.default_gem?
         spec_file_name = "#{spec.original_name}.gemspec.rz"
@@ -112,7 +112,7 @@ class Gem::Indexer
 
         marshal_zipped = Gem.deflate Marshal.dump(spec)
 
-        File.open marshal_name, 'wb' do |io|
+        File.open marshal_name, "wb" do |io|
           io.write marshal_zipped
         end
 
@@ -136,7 +136,7 @@ class Gem::Indexer
     say "Generating #{name} index"
 
     Gem.time "Generated #{name} index" do
-      File.open(file, 'wb') do |io|
+      File.open(file, "wb") do |io|
         specs = index.map do |*spec|
           # We have to splat here because latest_specs is an array, while the
           # others are hashes.
@@ -169,10 +169,10 @@ class Gem::Indexer
     latest_specs =
       Gem::Specification._latest_specs specs
 
-    build_modern_index(released.sort, @specs_index, 'specs')
-    build_modern_index(latest_specs.sort, @latest_specs_index, 'latest specs')
+    build_modern_index(released.sort, @specs_index, "specs")
+    build_modern_index(latest_specs.sort, @latest_specs_index, "latest specs")
     build_modern_index(prerelease.sort, @prerelease_specs_index,
-                       'prerelease specs')
+                       "prerelease specs")
 
     @files += [@specs_index,
                "#{@specs_index}.gz",
@@ -217,7 +217,7 @@ class Gem::Indexer
   def compress_indices
     say "Compressing indices"
 
-    Gem.time 'Compressed indices' do
+    Gem.time "Compressed indices" do
       if @build_modern
         gzip @specs_index
         gzip @latest_specs_index
@@ -252,7 +252,7 @@ class Gem::Indexer
 
     zipped = Gem.deflate data
 
-    File.open "#{filename}.#{extension}", 'wb' do |io|
+    File.open "#{filename}.#{extension}", "wb" do |io|
       io.write zipped
     end
   end
@@ -308,7 +308,7 @@ class Gem::Indexer
     end
 
     files = files.map do |path|
-      path.sub(/^#{Regexp.escape @directory}\/?/, '') # HACK?
+      path.sub(/^#{Regexp.escape @directory}\/?/, "") # HACK?
     end
 
     files.each do |file|
@@ -358,7 +358,7 @@ class Gem::Indexer
     end
 
     if updated_gems.empty?
-      say 'No new gems'
+      say "No new gems"
       terminate_interaction 0
     end
 
@@ -367,7 +367,7 @@ class Gem::Indexer
 
     files = build_marshal_gemspecs specs
 
-    Gem.time 'Updated indexes' do
+    Gem.time "Updated indexes" do
       update_specs_index released, @dest_specs_index, @specs_index
       update_specs_index released, @dest_latest_specs_index, @latest_specs_index
       update_specs_index(prerelease,
@@ -389,7 +389,7 @@ class Gem::Indexer
     files << "#{@prerelease_specs_index}.gz"
 
     files = files.map do |path|
-      path.sub(/^#{Regexp.escape @directory}\/?/, '') # HACK?
+      path.sub(/^#{Regexp.escape @directory}\/?/, "") # HACK?
     end
 
     files.each do |file|
@@ -420,7 +420,7 @@ class Gem::Indexer
 
     specs_index = compact_specs specs_index.uniq.sort
 
-    File.open dest, 'wb' do |io|
+    File.open dest, "wb" do |io|
       Marshal.dump specs_index, io
     end
   end
diff --git a/lib/rubygems/install_default_message.rb b/lib/rubygems/install_default_message.rb
index 052ef528e1..0d112a15df 100644
--- a/lib/rubygems/install_default_message.rb
+++ b/lib/rubygems/install_default_message.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
-require_relative '../rubygems'
-require_relative 'user_interaction'
+require_relative "../rubygems"
+require_relative "user_interaction"
 
 ##
 # A post-install hook that displays "Successfully installed
diff --git a/lib/rubygems/install_message.rb b/lib/rubygems/install_message.rb
index 861ead3770..2565f36261 100644
--- a/lib/rubygems/install_message.rb
+++ b/lib/rubygems/install_message.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
-require_relative '../rubygems'
-require_relative 'user_interaction'
+require_relative "../rubygems"
+require_relative "user_interaction"
 
 ##
 # A default post-install hook that displays "Successfully installed
diff --git a/lib/rubygems/install_update_options.rb b/lib/rubygems/install_update_options.rb
index 454104435d..79effcf21f 100644
--- a/lib/rubygems/install_update_options.rb
+++ b/lib/rubygems/install_update_options.rb
@@ -5,8 +5,8 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative '../rubygems'
-require_relative 'security_option'
+require_relative "../rubygems"
+require_relative "security_option"
 
 ##
 # Mixin methods for install and update options for Gem::Commands
@@ -18,22 +18,22 @@ module Gem::InstallUpdateOptions
   # Add the install/update options to the option parser.
 
   def add_install_update_options
-    add_option(:"Install/Update", '-i', '--install-dir DIR',
-               'Gem repository directory to get installed',
-               'gems') do |value, options|
+    add_option(:"Install/Update", "-i", "--install-dir DIR",
+               "Gem repository directory to get installed",
+               "gems") do |value, options|
       options[:install_dir] = File.expand_path(value)
     end
 
-    add_option(:"Install/Update", '-n', '--bindir DIR',
-               'Directory where executables will be',
-               'placed when the gem is installed') do |value, options|
+    add_option(:"Install/Update", "-n", "--bindir DIR",
+               "Directory where executables will be",
+               "placed when the gem is installed") do |value, options|
       options[:bin_dir] = File.expand_path(value)
     end
 
-    add_option(:"Install/Update", '--document [TYPES]', Array,
-               'Generate documentation for installed gems',
-               'List the documentation types you wish to',
-               'generate.  For example: rdoc,ri') do |value, options|
+    add_option(:"Install/Update", "--document [TYPES]", Array,
+               "Generate documentation for installed gems",
+               "List the documentation types you wish to",
+               "generate.  For example: rdoc,ri") do |value, options|
       options[:document] = case value
       when nil   then %w[ri]
       when false then []
@@ -41,63 +41,63 @@ module Gem::InstallUpdateOptions
       end
     end
 
-    add_option(:"Install/Update", '--build-root DIR',
-               'Temporary installation root. Useful for building',
-               'packages. Do not use this when installing remote gems.') do |value, options|
+    add_option(:"Install/Update", "--build-root DIR",
+               "Temporary installation root. Useful for building",
+               "packages. Do not use this when installing remote gems.") do |value, options|
       options[:build_root] = File.expand_path(value)
     end
 
-    add_option(:"Install/Update", '--vendor',
-               'Install gem into the vendor directory.',
-               'Only for use by gem repackagers.') do |value, options|
+    add_option(:"Install/Update", "--vendor",
+               "Install gem into the vendor directory.",
+               "Only for use by gem repackagers.") do |value, options|
       unless Gem.vendor_dir
-        raise Gem::OptionParser::InvalidOption.new 'your platform is not supported'
+        raise Gem::OptionParser::InvalidOption.new "your platform is not supported"
       end
 
       options[:vendor] = true
       options[:install_dir] = Gem.vendor_dir
     end
 
-    add_option(:"Install/Update", '-N', '--no-document',
-               'Disable documentation generation') do |value, options|
+    add_option(:"Install/Update", "-N", "--no-document",
+               "Disable documentation generation") do |value, options|
       options[:document] = []
     end
 
-    add_option(:"Install/Update", '-E', '--[no-]env-shebang',
+    add_option(:"Install/Update", "-E", "--[no-]env-shebang",
                "Rewrite the shebang line on installed",
                "scripts to use /usr/bin/env") do |value, options|
       options[:env_shebang] = value
     end
 
-    add_option(:"Install/Update", '-f', '--[no-]force',
-               'Force gem to install, bypassing dependency',
-               'checks') do |value, options|
+    add_option(:"Install/Update", "-f", "--[no-]force",
+               "Force gem to install, bypassing dependency",
+               "checks") do |value, options|
       options[:force] = value
     end
 
-    add_option(:"Install/Update", '-w', '--[no-]wrappers',
-               'Use bin wrappers for executables',
-               'Not available on dosish platforms') do |value, options|
+    add_option(:"Install/Update", "-w", "--[no-]wrappers",
+               "Use bin wrappers for executables",
+               "Not available on dosish platforms") do |value, options|
       options[:wrappers] = value
     end
 
     add_security_option
 
-    add_option(:"Install/Update", '--ignore-dependencies',
-               'Do not install any required dependent gems') do |value, options|
+    add_option(:"Install/Update", "--ignore-dependencies",
+               "Do not install any required dependent gems") do |value, options|
       options[:ignore_dependencies] = value
     end
 
-    add_option(:"Install/Update", '--[no-]format-executable',
-               'Make installed executable names match Ruby.',
-               'If Ruby is ruby18, foo_exec will be',
-               'foo_exec18') do |value, options|
+    add_option(:"Install/Update", "--[no-]format-executable",
+               "Make installed executable names match Ruby.",
+               "If Ruby is ruby18, foo_exec will be",
+               "foo_exec18") do |value, options|
       options[:format_executable] = value
     end
 
-    add_option(:"Install/Update",       '--[no-]user-install',
-               'Install in user\'s home directory instead',
-               'of GEM_HOME.') do |value, options|
+    add_option(:"Install/Update", "--[no-]user-install",
+               "Install in user's home directory instead",
+               "of GEM_HOME.") do |value, options|
       options[:user_install] = value
     end
 
@@ -133,9 +133,9 @@ module Gem::InstallUpdateOptions
       options[:post_install_message] = value
     end
 
-    add_option(:"Install/Update", '-g', '--file [FILE]',
-               'Read from a gem dependencies API file and',
-               'install the listed gems') do |v,o|
+    add_option(:"Install/Update", "-g", "--file [FILE]",
+               "Read from a gem dependencies API file and",
+               "install the listed gems") do |v,o|
       v = Gem::GEM_DEP_FILES.find do |file|
         File.exist? file
       end unless v
@@ -150,32 +150,32 @@ module Gem::InstallUpdateOptions
       options[:gemdeps] = v
     end
 
-    add_option(:"Install/Update", '--without GROUPS', Array,
-               'Omit the named groups (comma separated)',
-               'when installing from a gem dependencies',
-               'file') do |v,o|
+    add_option(:"Install/Update", "--without GROUPS", Array,
+               "Omit the named groups (comma separated)",
+               "when installing from a gem dependencies",
+               "file") do |v,o|
       options[:without_groups].concat v.map {|without| without.intern }
     end
 
-    add_option(:"Install/Update", '--default',
-               'Add the gem\'s full specification to',
-               'specifications/default and extract only its bin') do |v,o|
+    add_option(:"Install/Update", "--default",
+               "Add the gem's full specification to",
+               "specifications/default and extract only its bin") do |v,o|
       options[:install_as_default] = v
     end
 
-    add_option(:"Install/Update", '--explain',
-               'Rather than install the gems, indicate which would',
-               'be installed') do |v,o|
+    add_option(:"Install/Update", "--explain",
+               "Rather than install the gems, indicate which would",
+               "be installed") do |v,o|
       options[:explain] = v
     end
 
-    add_option(:"Install/Update", '--[no-]lock',
-               'Create a lock file (when used with -g/--file)') do |v,o|
+    add_option(:"Install/Update", "--[no-]lock",
+               "Create a lock file (when used with -g/--file)") do |v,o|
       options[:lock] = v
     end
 
-    add_option(:"Install/Update", '--[no-]suggestions',
-               'Suggest alternates when gems are not found') do |v,o|
+    add_option(:"Install/Update", "--[no-]suggestions",
+               "Suggest alternates when gems are not found") do |v,o|
       options[:suggest_alternate] = v
     end
   end
@@ -193,7 +193,7 @@ module Gem::InstallUpdateOptions
   # Default description for the gem install and update commands.
 
   def install_update_defaults_str
-    '--document=ri'
+    "--document=ri"
   end
 
 end
diff --git a/lib/rubygems/installer.rb b/lib/rubygems/installer.rb
index 7484145467..52307f6d93 100644
--- a/lib/rubygems/installer.rb
+++ b/lib/rubygems/installer.rb
@@ -5,12 +5,12 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'installer_uninstaller_utils'
-require_relative 'exceptions'
-require_relative 'deprecate'
-require_relative 'package'
-require_relative 'ext'
-require_relative 'user_interaction'
+require_relative "installer_uninstaller_utils"
+require_relative "exceptions"
+require_relative "deprecate"
+require_relative "package"
+require_relative "ext"
+require_relative "user_interaction"
 
 ##
 # The installer installs the files contained in the .gem into the Gem.home.
@@ -125,14 +125,14 @@ class Gem::Installer
       @spec = spec
     end
 
-    def extract_files(destination_dir, pattern = '*')
+    def extract_files(destination_dir, pattern = "*")
       FileUtils.mkdir_p destination_dir
 
       spec.files.each do |file|
         file = File.join destination_dir, file
         next if File.exist? file
         FileUtils.mkdir_p File.dirname(file)
-        File.open file, 'w' do |fp|
+        File.open file, "w" do |fp|
           fp.puts "# #{file}"
         end
       end
@@ -177,7 +177,7 @@ class Gem::Installer
   # :post_install_message:: Print gem post install message if true
 
   def initialize(package, options={})
-    require 'fileutils'
+    require "fileutils"
 
     @options = options
     @package = package
@@ -219,7 +219,7 @@ class Gem::Installer
     ruby_executable = false
     existing = nil
 
-    File.open generated_bin, 'rb' do |io|
+    File.open generated_bin, "rb" do |io|
       line = io.gets
       shebang = /^#!.*ruby/
 
@@ -256,7 +256,7 @@ class Gem::Installer
     question = "#{spec.name}'s executable \"#{filename}\" conflicts with ".dup
 
     if ruby_executable
-      question << (existing || 'an unknown executable')
+      question << (existing || "an unknown executable")
 
       return if ask_yes_no "#{question}\nOverwrite the executable?", false
 
@@ -474,7 +474,7 @@ class Gem::Installer
     if Gem.win_platform?
       script_name = formatted_program_filename(filename) + ".bat"
       script_path = File.join bindir, File.basename(script_name)
-      File.open script_path, 'w' do |file|
+      File.open script_path, "w" do |file|
         file.puts windows_stub_script(bindir, filename)
       end
 
@@ -504,7 +504,7 @@ class Gem::Installer
       dir_mode = options[:prog_mode] || (mode | 0111)
 
       unless dir_mode == mode
-        require 'fileutils'
+        require "fileutils"
         FileUtils.chmod dir_mode, bin_path
       end
 
@@ -541,10 +541,10 @@ class Gem::Installer
   def generate_bin_script(filename, bindir)
     bin_script_path = File.join bindir, formatted_program_filename(filename)
 
-    require 'fileutils'
+    require "fileutils"
     FileUtils.rm_f bin_script_path # prior install may have been --no-wrappers
 
-    File.open bin_script_path, 'wb', 0755 do |file|
+    File.open bin_script_path, "wb", 0755 do |file|
       file.print app_script_text(filename)
       file.chmod(options[:prog_mode] || 0755)
     end
@@ -565,7 +565,7 @@ class Gem::Installer
     if File.exist? dst
       if File.symlink? dst
         link = File.readlink(dst).split File::SEPARATOR
-        cur_version = Gem::Version.create(link[-3].sub(/^.*-/, ''))
+        cur_version = Gem::Version.create(link[-3].sub(/^.*-/, ""))
         return if spec.version < cur_version
       end
       File.unlink dst
@@ -684,9 +684,9 @@ class Gem::Installer
     @build_args = options[:build_args]
 
     unless @build_root.nil?
-      @bin_dir = File.join(@build_root, @bin_dir.gsub(/^[a-zA-Z]:/, ''))
-      @gem_home = File.join(@build_root, @gem_home.gsub(/^[a-zA-Z]:/, ''))
-      @plugins_dir = File.join(@build_root, @plugins_dir.gsub(/^[a-zA-Z]:/, ''))
+      @bin_dir = File.join(@build_root, @bin_dir.gsub(/^[a-zA-Z]:/, ""))
+      @gem_home = File.join(@build_root, @gem_home.gsub(/^[a-zA-Z]:/, ""))
+      @plugins_dir = File.join(@build_root, @plugins_dir.gsub(/^[a-zA-Z]:/, ""))
       alert_warning "You build with buildroot.\n  Build root: #{@build_root}\n  Bin dir: #{@bin_dir}\n  Gem home: #{@gem_home}\n  Plugins dir: #{@plugins_dir}"
     end
   end
@@ -697,7 +697,7 @@ class Gem::Installer
     user_bin_dir = @bin_dir || Gem.bindir(gem_home)
     user_bin_dir = user_bin_dir.tr(File::ALT_SEPARATOR, File::SEPARATOR) if File::ALT_SEPARATOR
 
-    path = ENV['PATH']
+    path = ENV["PATH"]
     path = path.tr(File::ALT_SEPARATOR, File::SEPARATOR) if File::ALT_SEPARATOR
 
     if Gem.win_platform?
@@ -708,7 +708,7 @@ class Gem::Installer
     path = path.split(File::PATH_SEPARATOR)
 
     unless path.include? user_bin_dir
-      unless !Gem.win_platform? && (path.include? user_bin_dir.sub(ENV['HOME'], '~'))
+      unless !Gem.win_platform? && (path.include? user_bin_dir.sub(ENV["HOME"], "~"))
         alert_warning "You don't have #{user_bin_dir} in your PATH,\n\t  gem executables will not run."
         self.class.path_warning = true
       end
@@ -788,7 +788,7 @@ TEXT
   end
 
   def gemdeps_load(name)
-    return '' if name == "bundler"
+    return "" if name == "bundler"
 
     <<-TEXT
 
@@ -824,7 +824,7 @@ TEXT
       TEXT
     elsif bindir.downcase.start_with? rb_topdir.downcase
       # stub within ruby folder, but not standard bin.  Portable
-      require 'pathname'
+      require "pathname"
       from = Pathname.new bindir
       to   = Pathname.new "#{rb_topdir}/bin"
       rel  = to.relative_path_from from
@@ -935,14 +935,14 @@ TEXT
   def write_build_info_file
     return if build_args.empty?
 
-    build_info_dir = File.join gem_home, 'build_info'
+    build_info_dir = File.join gem_home, "build_info"
 
     dir_mode = options[:dir_mode]
     FileUtils.mkdir_p build_info_dir, :mode => dir_mode && 0755
 
     build_info_file = File.join build_info_dir, "#{spec.full_name}.info"
 
-    File.open build_info_file, 'w' do |io|
+    File.open build_info_file, "w" do |io|
       build_args.each do |arg|
         io.puts arg
       end
@@ -955,7 +955,7 @@ TEXT
   # Writes the .gem file to the cache directory
 
   def write_cache_file
-    cache_file = File.join gem_home, 'cache', spec.file_name
+    cache_file = File.join gem_home, "cache", spec.file_name
     @package.copy_to cache_file
   end
 
@@ -987,7 +987,7 @@ TEXT
   end
 
   def load_relative_enabled?
-    rb_config["LIBRUBY_RELATIVE"] == 'yes'
+    rb_config["LIBRUBY_RELATIVE"] == "yes"
   end
 
   def bash_prolog_script
diff --git a/lib/rubygems/installer_uninstaller_utils.rb b/lib/rubygems/installer_uninstaller_utils.rb
index 2c8b7c635e..d97b4e29b1 100644
--- a/lib/rubygems/installer_uninstaller_utils.rb
+++ b/lib/rubygems/installer_uninstaller_utils.rb
@@ -9,12 +9,12 @@ module Gem::InstallerUninstallerUtils
     plugins = spec.plugins
     return if plugins.empty?
 
-    require 'pathname'
+    require "pathname"
 
     spec.plugins.each do |plugin|
       plugin_script_path = File.join plugins_dir, "#{spec.name}_plugin#{File.extname(plugin)}"
 
-      File.open plugin_script_path, 'wb' do |file|
+      File.open plugin_script_path, "wb" do |file|
         file.puts "require_relative '#{Pathname.new(plugin).relative_path_from(Pathname.new(plugins_dir))}'"
       end
 
diff --git a/lib/rubygems/local_remote_options.rb b/lib/rubygems/local_remote_options.rb
index 6b5e08bf1c..b2c2dea905 100644
--- a/lib/rubygems/local_remote_options.rb
+++ b/lib/rubygems/local_remote_options.rb
@@ -5,8 +5,8 @@
 # See LICENSE.txt for permissions.
 #++
 
-require 'uri'
-require_relative '../rubygems'
+require "uri"
+require_relative "../rubygems"
 
 ##
 # Mixin methods for local and remote Gem::Command options.
@@ -38,18 +38,18 @@ module Gem::LocalRemoteOptions
   # Add local/remote options to the command line parser.
 
   def add_local_remote_options
-    add_option(:"Local/Remote", '-l', '--local',
-               'Restrict operations to the LOCAL domain') do |value, options|
+    add_option(:"Local/Remote", "-l", "--local",
+               "Restrict operations to the LOCAL domain") do |value, options|
       options[:domain] = :local
     end
 
-    add_option(:"Local/Remote", '-r', '--remote',
-      'Restrict operations to the REMOTE domain') do |value, options|
+    add_option(:"Local/Remote", "-r", "--remote",
+      "Restrict operations to the REMOTE domain") do |value, options|
       options[:domain] = :remote
     end
 
-    add_option(:"Local/Remote", '-b', '--both',
-               'Allow LOCAL and REMOTE operations') do |value, options|
+    add_option(:"Local/Remote", "-b", "--both",
+               "Allow LOCAL and REMOTE operations") do |value, options|
       options[:domain] = :both
     end
 
@@ -64,7 +64,7 @@ module Gem::LocalRemoteOptions
   # Add the --bulk-threshold option
 
   def add_bulk_threshold_option
-    add_option(:"Local/Remote", '-B', '--bulk-threshold COUNT',
+    add_option(:"Local/Remote", "-B", "--bulk-threshold COUNT",
                "Threshold for switching to bulk",
                "synchronization (default #{Gem.configuration.bulk_threshold})") do
       |value, options|
@@ -76,8 +76,8 @@ module Gem::LocalRemoteOptions
   # Add the --clear-sources option
 
   def add_clear_sources_option
-    add_option(:"Local/Remote", '--clear-sources',
-               'Clear the gem sources') do |value, options|
+    add_option(:"Local/Remote", "--clear-sources",
+               "Clear the gem sources") do |value, options|
       Gem.sources = nil
       options[:sources_cleared] = true
     end
@@ -89,8 +89,8 @@ module Gem::LocalRemoteOptions
   def add_proxy_option
     accept_uri_http
 
-    add_option(:"Local/Remote", '-p', '--[no-]http-proxy [URL]', URI::HTTP,
-               'Use HTTP proxy for remote operations') do |value, options|
+    add_option(:"Local/Remote", "-p", "--[no-]http-proxy [URL]", URI::HTTP,
+               "Use HTTP proxy for remote operations") do |value, options|
       options[:http_proxy] = (value == false) ? :no_proxy : value
       Gem.configuration[:http_proxy] = options[:http_proxy]
     end
@@ -102,9 +102,9 @@ module Gem::LocalRemoteOptions
   def add_source_option
     accept_uri_http
 
-    add_option(:"Local/Remote", '-s', '--source URL', URI::HTTP,
-               'Append URL to list of remote gem sources') do |source, options|
-      source << '/' if source !~ /\/\z/
+    add_option(:"Local/Remote", "-s", "--source URL", URI::HTTP,
+               "Append URL to list of remote gem sources") do |source, options|
+      source << "/" if source !~ /\/\z/
 
       if options.delete :sources_cleared
         Gem.sources = [source]
@@ -118,8 +118,8 @@ module Gem::LocalRemoteOptions
   # Add the --update-sources option
 
   def add_update_sources_option
-    add_option(:Deprecated, '-u', '--[no-]update-sources',
-               'Update local source cache') do |value, options|
+    add_option(:Deprecated, "-u", "--[no-]update-sources",
+               "Update local source cache") do |value, options|
       Gem.configuration.update_sources = value
     end
   end
diff --git a/lib/rubygems/mock_gem_ui.rb b/lib/rubygems/mock_gem_ui.rb
index 914ecb9a71..5cc67ad099 100644
--- a/lib/rubygems/mock_gem_ui.rb
+++ b/lib/rubygems/mock_gem_ui.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative 'user_interaction'
+require_relative "user_interaction"
 
 ##
 # This Gem::StreamUI subclass records input and output to StringIO for
@@ -40,7 +40,7 @@ class Gem::MockGemUi < Gem::StreamUI
   end
 
   def initialize(input = "")
-    require 'stringio'
+    require "stringio"
     ins = StringIO.new input
     outs = StringIO.new
     errs = StringIO.new
diff --git a/lib/rubygems/name_tuple.rb b/lib/rubygems/name_tuple.rb
index c732d7f968..b9f330ee4d 100644
--- a/lib/rubygems/name_tuple.rb
+++ b/lib/rubygems/name_tuple.rb
@@ -48,7 +48,7 @@ class Gem::NameTuple
 
   def full_name
     case @platform
-    when nil, 'ruby', ''
+    when nil, "ruby", ""
       "#{@name}-#{@version}"
     else
       "#{@name}-#{@version}-#{@platform}"
diff --git a/lib/rubygems/optparse.rb b/lib/rubygems/optparse.rb
index 65be9f6b74..6ed718423c 100644
--- a/lib/rubygems/optparse.rb
+++ b/lib/rubygems/optparse.rb
@@ -1,3 +1,3 @@
 # frozen_string_literal: true
 
-require_relative 'optparse/lib/optparse'
+require_relative "optparse/lib/optparse"
diff --git a/lib/rubygems/package.rb b/lib/rubygems/package.rb
index 2dd8e8c28e..1e87837b0e 100644
--- a/lib/rubygems/package.rb
+++ b/lib/rubygems/package.rb
@@ -5,8 +5,8 @@
 #++
 
 require_relative "../rubygems"
-require_relative 'security'
-require_relative 'user_interaction'
+require_relative "security"
+require_relative "user_interaction"
 
 ##
 # Example using a Gem::Package
@@ -158,7 +158,7 @@ class Gem::Package
     return super unless gem.present?
 
     return super unless gem.start
-    return super unless gem.start.include? 'MD5SUM ='
+    return super unless gem.start.include? "MD5SUM ="
 
     Gem::Package::Old.new gem
   end
@@ -178,9 +178,9 @@ class Gem::Package
       tar = Gem::Package::TarReader.new io
       tar.each_entry do |entry|
         case entry.full_name
-        when 'metadata' then
+        when "metadata" then
           metadata = entry.read
-        when 'metadata.gz' then
+        when "metadata.gz" then
           metadata = Gem::Util.gunzip entry.read
         end
       end
@@ -193,7 +193,7 @@ class Gem::Package
   # Creates a new package that will read or write to the file +gem+.
 
   def initialize(gem, security_policy) # :notnew:
-    require 'zlib'
+    require "zlib"
 
     @gem = gem
 
@@ -229,7 +229,7 @@ class Gem::Package
       end
     end
 
-    tar.add_file_signed 'checksums.yaml.gz', 0444, @signer do |io|
+    tar.add_file_signed "checksums.yaml.gz", 0444, @signer do |io|
       gzip_to io do |gz_io|
         Psych.dump checksums_by_algorithm, gz_io
       end
@@ -241,7 +241,7 @@ class Gem::Package
   # and adds this file to the +tar+.
 
   def add_contents(tar) # :nodoc:
-    digests = tar.add_file_signed 'data.tar.gz', 0444, @signer do |io|
+    digests = tar.add_file_signed "data.tar.gz", 0444, @signer do |io|
       gzip_to io do |gz_io|
         Gem::Package::TarWriter.new gz_io do |data_tar|
           add_files data_tar
@@ -249,7 +249,7 @@ class Gem::Package
       end
     end
 
-    @checksums['data.tar.gz'] = digests
+    @checksums["data.tar.gz"] = digests
   end
 
   ##
@@ -266,7 +266,7 @@ class Gem::Package
       next unless stat.file?
 
       tar.add_file_simple file, stat.mode, stat.size do |dst_io|
-        File.open file, 'rb' do |src_io|
+        File.open file, "rb" do |src_io|
           dst_io.write src_io.read 16384 until src_io.eof?
         end
       end
@@ -277,13 +277,13 @@ class Gem::Package
   # Adds the package's Gem::Specification to the +tar+ file
 
   def add_metadata(tar) # :nodoc:
-    digests = tar.add_file_signed 'metadata.gz', 0444, @signer do |io|
+    digests = tar.add_file_signed "metadata.gz", 0444, @signer do |io|
       gzip_to io do |gz_io|
         gz_io.write @spec.to_yaml
       end
     end
 
-    @checksums['metadata.gz'] = digests
+    @checksums["metadata.gz"] = digests
   end
 
   ##
@@ -335,7 +335,7 @@ EOM
       gem_tar = Gem::Package::TarReader.new io
 
       gem_tar.each do |entry|
-        next unless entry.full_name == 'data.tar.gz'
+        next unless entry.full_name == "data.tar.gz"
 
         open_tar_gz entry do |pkg_tar|
           pkg_tar.each do |contents_entry|
@@ -387,7 +387,7 @@ EOM
       reader = Gem::Package::TarReader.new io
 
       reader.each do |entry|
-        next unless entry.full_name == 'data.tar.gz'
+        next unless entry.full_name == "data.tar.gz"
 
         extract_tar_gz entry, destination_dir, pattern
 
@@ -420,7 +420,7 @@ EOM
           real_destination = link_target.start_with?("/") ? link_target : File.expand_path(link_target, File.dirname(destination))
 
           raise Gem::Package::SymlinkError.new(entry.full_name, real_destination, destination_dir) unless
-            normalize_path(real_destination).start_with? normalize_path(destination_dir + '/')
+            normalize_path(real_destination).start_with? normalize_path(destination_dir + "/")
         end
 
         FileUtils.rm_rf destination
@@ -439,7 +439,7 @@ EOM
           directories << mkdir
         end
 
-        File.open destination, 'wb' do |out|
+        File.open destination, "wb" do |out|
           out.write entry.read
           FileUtils.chmod file_mode(entry.header.mode), destination
         end if entry.file?
@@ -481,13 +481,13 @@ EOM
 
   def install_location(filename, destination_dir) # :nodoc:
     raise Gem::Package::PathError.new(filename, destination_dir) if
-      filename.start_with? '/'
+      filename.start_with? "/"
 
     destination_dir = File.realpath(destination_dir)
     destination = File.expand_path(filename, destination_dir)
 
     raise Gem::Package::PathError.new(destination, destination_dir) unless
-      normalize_path(destination).start_with? normalize_path(destination_dir + '/')
+      normalize_path(destination).start_with? normalize_path(destination_dir + "/")
 
     destination.tap(&Gem::UNTAINT)
     destination
@@ -506,9 +506,9 @@ EOM
 
   def load_spec(entry) # :nodoc:
     case entry.full_name
-    when 'metadata' then
+    when "metadata" then
       @spec = Gem::Specification.from_yaml entry.read
-    when 'metadata.gz' then
+    when "metadata.gz" then
       Zlib::GzipReader.wrap(entry, external_encoding: Encoding::UTF_8) do |gzio|
         @spec = Gem::Specification.from_yaml gzio.read
       end
@@ -532,7 +532,7 @@ EOM
   def read_checksums(gem)
     Gem.load_yaml
 
-    @checksums = gem.seek 'checksums.yaml.gz' do |entry|
+    @checksums = gem.seek "checksums.yaml.gz" do |entry|
       Zlib::GzipReader.wrap entry do |gz_io|
         Gem::SafeYAML.safe_load gz_io.read
       end
@@ -544,7 +544,7 @@ EOM
   # certificate and key are not present only checksum generation is set up.
 
   def setup_signer(signer_options: {})
-    passphrase = ENV['GEM_PRIVATE_KEY_PASSPHRASE']
+    passphrase = ENV["GEM_PRIVATE_KEY_PASSPHRASE"]
     if @spec.signing_key
       @signer =
         Gem::Security::Signer.new(
@@ -651,7 +651,7 @@ EOM
     case file_name
     when "metadata", "metadata.gz" then
       load_spec entry
-    when 'data.tar.gz' then
+    when "data.tar.gz" then
       verify_gz entry
     end
   rescue
@@ -668,12 +668,12 @@ EOM
     end
 
     unless @spec
-      raise Gem::Package::FormatError.new 'package metadata is missing', @gem
+      raise Gem::Package::FormatError.new "package metadata is missing", @gem
     end
 
-    unless @files.include? 'data.tar.gz'
+    unless @files.include? "data.tar.gz"
       raise Gem::Package::FormatError.new \
-              'package content (data.tar.gz) is missing', @gem
+              "package content (data.tar.gz) is missing", @gem
     end
 
     if duplicates = @files.group_by {|f| f }.select {|k,v| v.size > 1 }.map(&:first) and duplicates.any?
@@ -693,12 +693,12 @@ EOM
   end
 end
 
-require_relative 'package/digest_io'
-require_relative 'package/source'
-require_relative 'package/file_source'
-require_relative 'package/io_source'
-require_relative 'package/old'
-require_relative 'package/tar_header'
-require_relative 'package/tar_reader'
-require_relative 'package/tar_reader/entry'
-require_relative 'package/tar_writer'
+require_relative "package/digest_io"
+require_relative "package/source"
+require_relative "package/file_source"
+require_relative "package/io_source"
+require_relative "package/old"
+require_relative "package/tar_header"
+require_relative "package/tar_reader"
+require_relative "package/tar_reader/entry"
+require_relative "package/tar_writer"
diff --git a/lib/rubygems/package/file_source.rb b/lib/rubygems/package/file_source.rb
index 114a950c77..14c7a9f6d2 100644
--- a/lib/rubygems/package/file_source.rb
+++ b/lib/rubygems/package/file_source.rb
@@ -22,10 +22,10 @@ class Gem::Package::FileSource < Gem::Package::Source # :nodoc: all
   end
 
   def with_write_io(&block)
-    File.open path, 'wb', &block
+    File.open path, "wb", &block
   end
 
   def with_read_io(&block)
-    File.open path, 'rb', &block
+    File.open path, "rb", &block
   end
 end
diff --git a/lib/rubygems/package/old.rb b/lib/rubygems/package/old.rb
index 301d403411..09a02d3ecd 100644
--- a/lib/rubygems/package/old.rb
+++ b/lib/rubygems/package/old.rb
@@ -19,8 +19,8 @@ class Gem::Package::Old < Gem::Package
   # cannot be written.
 
   def initialize(gem, security_policy)
-    require 'fileutils'
-    require 'zlib'
+    require "fileutils"
+    require "zlib"
     Gem.load_yaml
 
     @contents        = nil
@@ -41,7 +41,7 @@ class Gem::Package::Old < Gem::Package
       read_until_dashes io # spec
       header = file_list io
 
-      @contents = header.map {|file| file['path'] }
+      @contents = header.map {|file| file["path"] }
     end
   end
 
@@ -59,7 +59,7 @@ class Gem::Package::Old < Gem::Package
       raise Gem::Exception, errstr unless header
 
       header.each do |entry|
-        full_name = entry['path']
+        full_name = entry["path"]
 
         destination = install_location full_name, destination_dir
 
@@ -73,13 +73,13 @@ class Gem::Package::Old < Gem::Package
         file_data = Zlib::Inflate.inflate file_data
 
         raise Gem::Package::FormatError, "#{full_name} in #{@gem} is corrupt" if
-          file_data.length != entry['size'].to_i
+          file_data.length != entry["size"].to_i
 
         FileUtils.rm_rf destination
 
         FileUtils.mkdir_p File.dirname(destination), :mode => dir_mode && 0755
 
-        File.open destination, 'wb', file_mode(entry['mode']) do |out|
+        File.open destination, "wb", file_mode(entry["mode"]) do |out|
           out.write file_data
         end
 
@@ -119,7 +119,7 @@ class Gem::Package::Old < Gem::Package
     loop do
       line = io.gets
 
-      return if line.chomp == '__END__'
+      return if line.chomp == "__END__"
       break unless line
     end
 
@@ -160,7 +160,7 @@ class Gem::Package::Old < Gem::Package
     return true unless @security_policy
 
     raise Gem::Security::Exception,
-          'old format gems do not contain signatures and cannot be verified' if
+          "old format gems do not contain signatures and cannot be verified" if
       @security_policy.verify_data
 
     true
diff --git a/lib/rubygems/package/tar_header.rb b/lib/rubygems/package/tar_header.rb
index ce9b49e3eb..fb70765dde 100644
--- a/lib/rubygems/package/tar_header.rb
+++ b/lib/rubygems/package/tar_header.rb
@@ -53,42 +53,42 @@ class Gem::Package::TarHeader
   ##
   # Pack format for a tar header
 
-  PACK_FORMAT = 'a100' + # name
-                'a8'   + # mode
-                'a8'   + # uid
-                'a8'   + # gid
-                'a12'  + # size
-                'a12'  + # mtime
-                'a7a'  + # chksum
-                'a'    + # typeflag
-                'a100' + # linkname
-                'a6'   + # magic
-                'a2'   + # version
-                'a32'  + # uname
-                'a32'  + # gname
-                'a8'   + # devmajor
-                'a8'   + # devminor
-                'a155'   # prefix
+  PACK_FORMAT = "a100" + # name
+                "a8"   + # mode
+                "a8"   + # uid
+                "a8"   + # gid
+                "a12"  + # size
+                "a12"  + # mtime
+                "a7a"  + # chksum
+                "a"    + # typeflag
+                "a100" + # linkname
+                "a6"   + # magic
+                "a2"   + # version
+                "a32"  + # uname
+                "a32"  + # gname
+                "a8"   + # devmajor
+                "a8"   + # devminor
+                "a155"   # prefix
 
   ##
   # Unpack format for a tar header
 
-  UNPACK_FORMAT = 'A100' + # name
-                  'A8'   + # mode
-                  'A8'   + # uid
-                  'A8'   + # gid
-                  'A12'  + # size
-                  'A12'  + # mtime
-                  'A8'   + # checksum
-                  'A'    + # typeflag
-                  'A100' + # linkname
-                  'A6'   + # magic
-                  'A2'   + # version
-                  'A32'  + # uname
-                  'A32'  + # gname
-                  'A8'   + # devmajor
-                  'A8'   + # devminor
-                  'A155'   # prefix
+  UNPACK_FORMAT = "A100" + # name
+                  "A8"   + # mode
+                  "A8"   + # uid
+                  "A8"   + # gid
+                  "A12"  + # size
+                  "A12"  + # mtime
+                  "A8"   + # checksum
+                  "A"    + # typeflag
+                  "A100" + # linkname
+                  "A6"   + # magic
+                  "A2"   + # version
+                  "A32"  + # uname
+                  "A32"  + # gname
+                  "A8"   + # devmajor
+                  "A8"   + # devminor
+                  "A155"   # prefix
 
   attr_reader(*FIELDS)
 
@@ -134,7 +134,7 @@ class Gem::Package::TarHeader
     # \ff flags a negative 256-based number
     # In case we have a match, parse it as a signed binary value
     # in big-endian order, except that the high-order bit is ignored.
-    return str.unpack('N2').last if str =~ /\A[\x80\xff]/n
+    return str.unpack("N2").last if str =~ /\A[\x80\xff]/n
     strict_oct(str)
   end
 
diff --git a/lib/rubygems/package/tar_reader.rb b/lib/rubygems/package/tar_reader.rb
index 41121f3bfb..cdc3fdc015 100644
--- a/lib/rubygems/package/tar_reader.rb
+++ b/lib/rubygems/package/tar_reader.rb
@@ -121,4 +121,4 @@ class Gem::Package::TarReader
   end
 end
 
-require_relative 'tar_reader/entry'
+require_relative "tar_reader/entry"
diff --git a/lib/rubygems/package/tar_reader/entry.rb b/lib/rubygems/package/tar_reader/entry.rb
index 5865599d3a..8634381c18 100644
--- a/lib/rubygems/package/tar_reader/entry.rb
+++ b/lib/rubygems/package/tar_reader/entry.rb
@@ -68,9 +68,9 @@ class Gem::Package::TarReader::Entry
       @header.name
     end
   rescue ArgumentError => e
-    raise unless e.message == 'string contains null byte'
+    raise unless e.message == "string contains null byte"
     raise Gem::Package::TarInvalidError,
-          'tar is corrupt, name contains null byte'
+          "tar is corrupt, name contains null byte"
   end
 
   ##
diff --git a/lib/rubygems/package/tar_writer.rb b/lib/rubygems/package/tar_writer.rb
index 877cc167c9..6f068f50c2 100644
--- a/lib/rubygems/package/tar_writer.rb
+++ b/lib/rubygems/package/tar_writer.rb
@@ -166,7 +166,7 @@ class Gem::Package::TarWriter
   def add_file_signed(name, mode, signer)
     digest_algorithms = [
       signer.digest_algorithm,
-      Gem::Security.create_digest('SHA512'),
+      Gem::Security.create_digest("SHA512"),
     ].compact.uniq
 
     digests = add_file_digest name, mode, digest_algorithms do |io|
@@ -304,14 +304,14 @@ class Gem::Package::TarWriter
       raise Gem::Package::TooLongFileName.new("File \"#{name}\" has a too long path (should be 256 or less)")
     end
 
-    prefix = ''
+    prefix = ""
     if name.bytesize > 100
-      parts = name.split('/', -1) # parts are never empty here
+      parts = name.split("/", -1) # parts are never empty here
       name = parts.pop            # initially empty for names with a trailing slash ("foo/.../bar/")
-      prefix = parts.join('/')    # if empty, then it's impossible to split (parts is empty too)
+      prefix = parts.join("/")    # if empty, then it's impossible to split (parts is empty too)
       while !parts.empty? && (prefix.bytesize > 155 || name.empty?)
-        name = parts.pop + '/' + name
-        prefix = parts.join('/')
+        name = parts.pop + "/" + name
+        prefix = parts.join("/")
       end
 
       if name.bytesize > 100 or prefix.empty?
diff --git a/lib/rubygems/package_task.rb b/lib/rubygems/package_task.rb
index bb48616b0e..8432bc5806 100644
--- a/lib/rubygems/package_task.rb
+++ b/lib/rubygems/package_task.rb
@@ -20,9 +20,9 @@
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-require_relative '../rubygems'
-require_relative 'package'
-require 'rake/packagetask'
+require_relative "../rubygems"
+require_relative "package"
+require "rake/packagetask"
 
 ##
 # Create a package based upon a Gem::Specification.  Gem packages, as well as
@@ -113,7 +113,7 @@ class Gem::PackageTask < Rake::PackageTask
           Gem::Package.build gem_spec
 
           verbose trace do
-            mv gem_file, '..'
+            mv gem_file, ".."
           end
         end
       end
diff --git a/lib/rubygems/platform.rb b/lib/rubygems/platform.rb
index 8fcabf164d..607e3906d6 100644
--- a/lib/rubygems/platform.rb
+++ b/lib/rubygems/platform.rb
@@ -12,7 +12,7 @@ class Gem::Platform
   attr_accessor :cpu, :os, :version
 
   def self.local
-    arch = RbConfig::CONFIG['arch']
+    arch = RbConfig::CONFIG["arch"]
     arch = "#{arch}_60" if arch =~ /mswin(?:32|64)$/
     @local ||= new(arch)
   end
@@ -56,7 +56,7 @@ class Gem::Platform
     case arch
     when Gem::Platform::CURRENT then
       Gem::Platform.local
-    when Gem::Platform::RUBY, nil, '' then
+    when Gem::Platform::RUBY, nil, "" then
       Gem::Platform::RUBY
     else
       super
@@ -68,7 +68,7 @@ class Gem::Platform
     when Array then
       @cpu, @os, @version = arch
     when String then
-      arch = arch.split '-'
+      arch = arch.split "-"
 
       if arch.length > 2 and arch.last !~ /\d/ # reassemble x86-linux-gnu
         extra = arch.pop
@@ -78,7 +78,7 @@ class Gem::Platform
       cpu = arch.shift
 
       @cpu = case cpu
-      when /i\d86/ then 'x86'
+      when /i\d86/ then "x86"
       else cpu
       end
 
@@ -91,31 +91,31 @@ class Gem::Platform
       @cpu, os = nil, cpu if os.nil? # legacy jruby
 
       @os, @version = case os
-      when /aix(\d+)?/ then             [ 'aix',       $1  ]
-      when /cygwin/ then                [ 'cygwin',    nil ]
-      when /darwin(\d+)?/ then          [ 'darwin',    $1  ]
-      when /^macruby$/ then             [ 'macruby',   nil ]
-      when /freebsd(\d+)?/ then         [ 'freebsd',   $1  ]
-      when /hpux(\d+)?/ then            [ 'hpux',      $1  ]
-      when /^java$/, /^jruby$/ then     [ 'java',      nil ]
-      when /^java([\d.]*)/ then         [ 'java',      $1  ]
-      when /^dalvik(\d+)?$/ then        [ 'dalvik',    $1  ]
-      when /^dotnet$/ then              [ 'dotnet',    nil ]
-      when /^dotnet([\d.]*)/ then       [ 'dotnet',    $1  ]
-      when /linux-?((?!gnu)\w+)?/ then  [ 'linux',     $1  ]
-      when /mingw32/ then               [ 'mingw32',   nil ]
-      when /mingw-?(\w+)?/ then         [ 'mingw',     $1  ]
+      when /aix(\d+)?/ then             [ "aix",       $1  ]
+      when /cygwin/ then                [ "cygwin",    nil ]
+      when /darwin(\d+)?/ then          [ "darwin",    $1  ]
+      when /^macruby$/ then             [ "macruby",   nil ]
+      when /freebsd(\d+)?/ then         [ "freebsd",   $1  ]
+      when /hpux(\d+)?/ then            [ "hpux",      $1  ]
+      when /^java$/, /^jruby$/ then     [ "java",      nil ]
+      when /^java([\d.]*)/ then         [ "java",      $1  ]
+      when /^dalvik(\d+)?$/ then        [ "dalvik",    $1  ]
+      when /^dotnet$/ then              [ "dotnet",    nil ]
+      when /^dotnet([\d.]*)/ then       [ "dotnet",    $1  ]
+      when /linux-?((?!gnu)\w+)?/ then  [ "linux",     $1  ]
+      when /mingw32/ then               [ "mingw32",   nil ]
+      when /mingw-?(\w+)?/ then         [ "mingw",     $1  ]
       when /(mswin\d+)(\_(\d+))?/ then
         os, version = $1, $3
-        @cpu = 'x86' if @cpu.nil? and os =~ /32$/
+        @cpu = "x86" if @cpu.nil? and os =~ /32$/
         [os, version]
-      when /netbsdelf/ then             [ 'netbsdelf', nil ]
-      when /openbsd(\d+\.\d+)?/ then    [ 'openbsd',   $1  ]
-      when /bitrig(\d+\.\d+)?/ then     [ 'bitrig',    $1  ]
-      when /solaris(\d+\.\d+)?/ then    [ 'solaris',   $1  ]
+      when /netbsdelf/ then             [ "netbsdelf", nil ]
+      when /openbsd(\d+\.\d+)?/ then    [ "openbsd",   $1  ]
+      when /bitrig(\d+\.\d+)?/ then     [ "bitrig",    $1  ]
+      when /solaris(\d+\.\d+)?/ then    [ "solaris",   $1  ]
       # test
       when /^(\w+_platform)(\d+)?/ then [ $1,          $2  ]
-      else                              [ 'unknown',   nil ]
+      else                              [ "unknown",   nil ]
       end
     when Gem::Platform then
       @cpu = arch.cpu
@@ -131,7 +131,7 @@ class Gem::Platform
   end
 
   def to_s
-    to_a.compact.join '-'
+    to_a.compact.join "-"
   end
 
   ##
@@ -160,12 +160,12 @@ class Gem::Platform
     return nil unless Gem::Platform === other
 
     # universal-mingw32 matches x64-mingw-ucrt
-    return true if (@cpu == 'universal' or other.cpu == 'universal') and
-                   @os.start_with?('mingw') and other.os.start_with?('mingw')
+    return true if (@cpu == "universal" or other.cpu == "universal") and
+                   @os.start_with?("mingw") and other.os.start_with?("mingw")
 
     # cpu
-    ([nil,'universal'].include?(@cpu) or [nil, 'universal'].include?(other.cpu) or @cpu == other.cpu or
-    (@cpu == 'arm' and other.cpu.start_with?("arm"))) and
+    ([nil,"universal"].include?(@cpu) or [nil, "universal"].include?(other.cpu) or @cpu == other.cpu or
+    (@cpu == "arm" and other.cpu.start_with?("arm"))) and
 
     # os
     @os == other.os and
@@ -184,17 +184,17 @@ class Gem::Platform
     when String then
       # This data is from http://gems.rubyforge.org/gems/yaml on 19 Aug 2007
       other = case other
-      when /^i686-darwin(\d)/     then ['x86',       'darwin',  $1    ]
-      when /^i\d86-linux/         then ['x86',       'linux',   nil   ]
-      when 'java', 'jruby'        then [nil,         'java',    nil   ]
-      when /^dalvik(\d+)?$/       then [nil,         'dalvik',  $1    ]
-      when /dotnet(\-(\d+\.\d+))?/ then ['universal','dotnet',  $2    ]
-      when /mswin32(\_(\d+))?/    then ['x86',       'mswin32', $2    ]
-      when /mswin64(\_(\d+))?/    then ['x64',       'mswin64', $2    ]
-      when 'powerpc-darwin'       then ['powerpc',   'darwin',  nil   ]
-      when /powerpc-darwin(\d)/   then ['powerpc',   'darwin',  $1    ]
-      when /sparc-solaris2.8/     then ['sparc',     'solaris', '2.8' ]
-      when /universal-darwin(\d)/ then ['universal', 'darwin',  $1    ]
+      when /^i686-darwin(\d)/     then ["x86",       "darwin",  $1    ]
+      when /^i\d86-linux/         then ["x86",       "linux",   nil   ]
+      when "java", "jruby"        then [nil,         "java",    nil   ]
+      when /^dalvik(\d+)?$/       then [nil,         "dalvik",  $1    ]
+      when /dotnet(\-(\d+\.\d+))?/ then ["universal","dotnet",  $2    ]
+      when /mswin32(\_(\d+))?/    then ["x86",       "mswin32", $2    ]
+      when /mswin64(\_(\d+))?/    then ["x64",       "mswin64", $2    ]
+      when "powerpc-darwin"       then ["powerpc",   "darwin",  nil   ]
+      when /powerpc-darwin(\d)/   then ["powerpc",   "darwin",  $1    ]
+      when /sparc-solaris2.8/     then ["sparc",     "solaris", "2.8" ]
+      when /universal-darwin(\d)/ then ["universal", "darwin",  $1    ]
       else                             other
       end
 
@@ -210,11 +210,11 @@ class Gem::Platform
   # A pure-Ruby gem that may use Gem::Specification#extensions to build
   # binary files.
 
-  RUBY = 'ruby'.freeze
+  RUBY = "ruby".freeze
 
   ##
   # A platform-specific gem that is built for the packaging Ruby's platform.
   # This will be replaced with Gem::Platform::local.
 
-  CURRENT = 'current'.freeze
+  CURRENT = "current".freeze
 end
diff --git a/lib/rubygems/psych_tree.rb b/lib/rubygems/psych_tree.rb
index 6f399a289e..b90f9f7d1d 100644
--- a/lib/rubygems/psych_tree.rb
+++ b/lib/rubygems/psych_tree.rb
@@ -7,7 +7,7 @@ module Gem
       end unless respond_to? :create
 
       def visit_String(str)
-        return super unless str == '=' # or whatever you want
+        return super unless str == "=" # or whatever you want
 
         quote = Psych::Nodes::Scalar::SINGLE_QUOTED
         @emitter.scalar str, nil, nil, false, true, quote
diff --git a/lib/rubygems/query_utils.rb b/lib/rubygems/query_utils.rb
index e0c71c43cb..4601d9374c 100644
--- a/lib/rubygems/query_utils.rb
+++ b/lib/rubygems/query_utils.rb
@@ -1,9 +1,9 @@
 # frozen_string_literal: true
 
-require_relative 'local_remote_options'
-require_relative 'spec_fetcher'
-require_relative 'version_option'
-require_relative 'text'
+require_relative "local_remote_options"
+require_relative "spec_fetcher"
+require_relative "version_option"
+require_relative "text"
 
 module Gem::QueryUtils
 
@@ -12,41 +12,41 @@ module Gem::QueryUtils
   include Gem::VersionOption
 
   def add_query_options
-    add_option('-i', '--[no-]installed',
-               'Check for installed gem') do |value, options|
+    add_option("-i", "--[no-]installed",
+               "Check for installed gem") do |value, options|
       options[:installed] = value
     end
 
-    add_option('-I', 'Equivalent to --no-installed') do |value, options|
+    add_option("-I", "Equivalent to --no-installed") do |value, options|
       options[:installed] = false
     end
 
     add_version_option command, "for use with --installed"
 
-    add_option('-d', '--[no-]details',
-               'Display detailed information of gem(s)') do |value, options|
+    add_option("-d", "--[no-]details",
+               "Display detailed information of gem(s)") do |value, options|
       options[:details] = value
     end
 
-    add_option('--[no-]versions',
-               'Display only gem names') do |value, options|
+    add_option("--[no-]versions",
+               "Display only gem names") do |value, options|
       options[:versions] = value
       options[:details] = false unless value
     end
 
-    add_option('-a', '--all',
-               'Display all gem versions') do |value, options|
+    add_option("-a", "--all",
+               "Display all gem versions") do |value, options|
       options[:all] = value
     end
 
-    add_option('-e', '--exact',
-               'Name of gem(s) to query on matches the',
-               'provided STRING') do |value, options|
+    add_option("-e", "--exact",
+               "Name of gem(s) to query on matches the",
+               "provided STRING") do |value, options|
       options[:exact] = value
     end
 
-    add_option('--[no-]prerelease',
-               'Display prerelease versions') do |value, options|
+    add_option("--[no-]prerelease",
+               "Display prerelease versions") do |value, options|
       options[:prerelease] = value
     end
 
@@ -257,7 +257,7 @@ module Gem::QueryUtils
 
           if pls != [Gem::Platform::RUBY]
             platform_list = [pls.delete(Gem::Platform::RUBY), *pls.sort].compact
-            out = platform_list.unshift(out).join(' ')
+            out = platform_list.unshift(out).join(" ")
           end
 
           out
@@ -284,7 +284,7 @@ module Gem::QueryUtils
 
   def spec_authors(entry, spec)
     authors = "Author#{spec.authors.length > 1 ? 's' : ''}: ".dup
-    authors << spec.authors.join(', ')
+    authors << spec.authors.join(", ")
     entry << format_text(authors, 68, 4)
   end
 
@@ -298,7 +298,7 @@ module Gem::QueryUtils
     return if spec.license.nil? or spec.license.empty?
 
     licenses = "License#{spec.licenses.length > 1 ? 's' : ''}: ".dup
-    licenses << spec.licenses.join(', ')
+    licenses << spec.licenses.join(", ")
     entry << "\n" << format_text(licenses, 68, 4)
   end
 
@@ -306,15 +306,15 @@ module Gem::QueryUtils
     return unless spec.loaded_from
 
     if specs.length == 1
-      default = spec.default_gem? ? ' (default)' : nil
+      default = spec.default_gem? ? " (default)" : nil
       entry << "\n" << "    Installed at#{default}: #{spec.base_dir}"
     else
-      label = 'Installed at'
+      label = "Installed at"
       specs.each do |s|
         version = s.version.to_s
-        version << ', default' if s.default_gem?
+        version << ", default" if s.default_gem?
         entry << "\n" << "    #{label} (#{version}): #{s.base_dir}"
-        label = ' ' * label.length
+        label = " " * label.length
       end
     end
   end
@@ -327,7 +327,7 @@ module Gem::QueryUtils
     return unless non_ruby
 
     if platforms.length == 1
-      title = platforms.values.length == 1 ? 'Platform' : 'Platforms'
+      title = platforms.values.length == 1 ? "Platform" : "Platforms"
       entry << "    #{title}: #{platforms.values.sort.join(', ')}\n"
     else
       entry << "    Platforms:\n"
@@ -336,7 +336,7 @@ module Gem::QueryUtils
 
       sorted_platforms.each do |version, pls|
         label = "        #{version}: "
-        data = format_text pls.sort.join(', '), 68, label.length
+        data = format_text pls.sort.join(", "), 68, label.length
         data[0, label.length] = label
         entry << data << "\n"
       end
diff --git a/lib/rubygems/rdoc.rb b/lib/rubygems/rdoc.rb
index ac5e8f0822..769ec61d1e 100644
--- a/lib/rubygems/rdoc.rb
+++ b/lib/rubygems/rdoc.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
-require_relative '../rubygems'
+require_relative "../rubygems"
 
 begin
-  require 'rdoc/rubygems_hook'
+  require "rdoc/rubygems_hook"
   module Gem
     RDoc = ::RDoc::RubygemsHook
   end
diff --git a/lib/rubygems/remote_fetcher.rb b/lib/rubygems/remote_fetcher.rb
index b8f9f90cee..d028739861 100644
--- a/lib/rubygems/remote_fetcher.rb
+++ b/lib/rubygems/remote_fetcher.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
-require_relative '../rubygems'
-require_relative 'request'
-require_relative 'request/connection_pools'
-require_relative 's3_uri_signer'
-require_relative 'uri_formatter'
-require_relative 'uri'
-require_relative 'user_interaction'
+require_relative "../rubygems"
+require_relative "request"
+require_relative "request/connection_pools"
+require_relative "s3_uri_signer"
+require_relative "uri_formatter"
+require_relative "uri"
+require_relative "user_interaction"
 
 ##
 # RemoteFetcher handles the details of fetching gems and gem information from
@@ -72,10 +72,10 @@ class Gem::RemoteFetcher
   #            fetching the gem.
 
   def initialize(proxy=nil, dns=nil, headers={})
-    require_relative 'core_ext/tcpsocket_init' if Gem.configuration.ipv4_fallback_enabled
-    require 'net/http'
-    require 'stringio'
-    require 'uri'
+    require_relative "core_ext/tcpsocket_init" if Gem.configuration.ipv4_fallback_enabled
+    require "net/http"
+    require "stringio"
+    require "uri"
 
     Socket.do_not_reverse_lookup = true
 
@@ -136,7 +136,7 @@ class Gem::RemoteFetcher
     # REFACTOR: split this up and dispatch on scheme (eg download_http)
     # REFACTOR: be sure to clean up fake fetcher when you do this... cleaner
     case scheme
-    when 'http', 'https', 's3' then
+    when "http", "https", "s3" then
       unless File.exist? local_gem_path
         begin
           verbose "Downloading gem #{gem_file_name}"
@@ -156,12 +156,12 @@ class Gem::RemoteFetcher
           self.cache_update_path remote_gem_path, local_gem_path
         end
       end
-    when 'file' then
+    when "file" then
       begin
         path = source_uri.path
-        path = File.dirname(path) if File.extname(path) == '.gem'
+        path = File.dirname(path) if File.extname(path) == ".gem"
 
-        remote_gem_path = Gem::Util.correct_for_windows_path(File.join(path, 'gems', gem_file_name))
+        remote_gem_path = Gem::Util.correct_for_windows_path(File.join(path, "gems", gem_file_name))
 
         FileUtils.cp(remote_gem_path, local_gem_path)
       rescue Errno::EACCES
@@ -171,7 +171,7 @@ class Gem::RemoteFetcher
       verbose "Using local gem #{local_gem_path}"
     when nil then # TODO test for local overriding cache
       source_path = if Gem.win_platform? && source_uri.scheme &&
-                       !source_uri.path.include?(':')
+                       !source_uri.path.include?(":")
         "#{source_uri.scheme}:#{source_uri.path}"
       else
         source_uri.path
@@ -216,9 +216,9 @@ class Gem::RemoteFetcher
       head ? response : response.body
     when Net::HTTPMovedPermanently, Net::HTTPFound, Net::HTTPSeeOther,
          Net::HTTPTemporaryRedirect then
-      raise FetchError.new('too many redirects', uri) if depth > 10
+      raise FetchError.new("too many redirects", uri) if depth > 10
 
-      unless location = response['Location']
+      unless location = response["Location"]
         raise FetchError.new("redirecting but no redirect location was given", uri)
       end
       location = Gem::Uri.new location
@@ -312,7 +312,7 @@ class Gem::RemoteFetcher
   end
 
   def https?(uri)
-    uri.scheme.downcase == 'https'
+    uri.scheme.downcase == "https"
   end
 
   def close_all
diff --git a/lib/rubygems/request.rb b/lib/rubygems/request.rb
index 6d6c2d8de8..d15ba91209 100644
--- a/lib/rubygems/request.rb
+++ b/lib/rubygems/request.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
-require 'net/http'
-require_relative 'user_interaction'
+require "net/http"
+require_relative "user_interaction"
 
 class Gem::Request
   extend Gem::UserInteraction
@@ -44,7 +44,7 @@ class Gem::Request
   end
 
   def self.configure_connection_for_https(connection, cert_files)
-    raise Gem::Exception.new('OpenSSL is not available. Install OpenSSL and rebuild Ruby (preferred) or use non-HTTPS sources') unless Gem::HAVE_OPENSSL
+    raise Gem::Exception.new("OpenSSL is not available. Install OpenSSL and rebuild Ruby (preferred) or use non-HTTPS sources") unless Gem::HAVE_OPENSSL
 
     connection.use_ssl = true
     connection.verify_mode =
@@ -96,10 +96,10 @@ class Gem::Request
     return unless cert
     case error_number
     when OpenSSL::X509::V_ERR_CERT_HAS_EXPIRED then
-      require 'time'
+      require "time"
       "Certificate #{cert.subject} expired at #{cert.not_after.iso8601}"
     when OpenSSL::X509::V_ERR_CERT_NOT_YET_VALID then
-      require 'time'
+      require "time"
       "Certificate #{cert.subject} not valid until #{cert.not_before.iso8601}"
     when OpenSSL::X509::V_ERR_CERT_REJECTED then
       "Certificate #{cert.subject} is rejected"
@@ -140,13 +140,13 @@ class Gem::Request
                          Gem::UriFormatter.new(@uri.password).unescape
     end
 
-    request.add_field 'User-Agent', @user_agent
-    request.add_field 'Connection', 'keep-alive'
-    request.add_field 'Keep-Alive', '30'
+    request.add_field "User-Agent", @user_agent
+    request.add_field "Connection", "keep-alive"
+    request.add_field "Keep-Alive", "30"
 
     if @last_modified
-      require 'time'
-      request.add_field 'If-Modified-Since', @last_modified.httpdate
+      require "time"
+      request.add_field "If-Modified-Since", @last_modified.httpdate
     end
 
     yield request if block_given?
@@ -158,7 +158,7 @@ class Gem::Request
   # Returns a proxy URI for the given +scheme+ if one is set in the
   # environment variables.
 
-  def self.get_proxy_from_env(scheme = 'http')
+  def self.get_proxy_from_env(scheme = "http")
     _scheme = scheme.downcase
     _SCHEME = scheme.upcase
     env_proxy = ENV["#{_scheme}_proxy"] || ENV["#{_SCHEME}_PROXY"]
@@ -166,8 +166,8 @@ class Gem::Request
     no_env_proxy = env_proxy.nil? || env_proxy.empty?
 
     if no_env_proxy
-      return (_scheme == 'https' || _scheme == 'http') ?
-        :no_proxy : get_proxy_from_env('http')
+      return (_scheme == "https" || _scheme == "http") ?
+        :no_proxy : get_proxy_from_env("http")
     end
 
     require "uri"
@@ -229,14 +229,14 @@ class Gem::Request
 
       reset connection
 
-      raise Gem::RemoteFetcher::FetchError.new('too many bad responses', @uri) if bad_response
+      raise Gem::RemoteFetcher::FetchError.new("too many bad responses", @uri) if bad_response
 
       bad_response = true
       retry
     rescue Net::HTTPFatalError
       verbose "fatal error"
 
-      raise Gem::RemoteFetcher::FetchError.new('fatal error', @uri)
+      raise Gem::RemoteFetcher::FetchError.new("fatal error", @uri)
     # HACK work around EOFError bug in Net::HTTP
     # NOTE Errno::ECONNABORTED raised a lot on Windows, and make impossible
     # to install gems.
@@ -246,7 +246,7 @@ class Gem::Request
       requests = @requests[connection.object_id]
       verbose "connection reset after #{requests} requests, retrying"
 
-      raise Gem::RemoteFetcher::FetchError.new('too many connection resets', @uri) if retried
+      raise Gem::RemoteFetcher::FetchError.new("too many connection resets", @uri) if retried
 
       reset connection
 
@@ -273,7 +273,7 @@ class Gem::Request
     ua = "RubyGems/#{Gem::VERSION} #{Gem::Platform.local}".dup
 
     ruby_version = RUBY_VERSION
-    ruby_version += 'dev' if RUBY_PATCHLEVEL == -1
+    ruby_version += "dev" if RUBY_PATCHLEVEL == -1
 
     ua << " Ruby/#{ruby_version} (#{RUBY_RELEASE_DATE}"
     if RUBY_PATCHLEVEL >= 0
@@ -283,12 +283,12 @@ class Gem::Request
     end
     ua << ")"
 
-    ua << " #{RUBY_ENGINE}" if RUBY_ENGINE != 'ruby'
+    ua << " #{RUBY_ENGINE}" if RUBY_ENGINE != "ruby"
 
     ua
   end
 end
 
-require_relative 'request/http_pool'
-require_relative 'request/https_pool'
-require_relative 'request/connection_pools'
+require_relative "request/http_pool"
+require_relative "request/https_pool"
+require_relative "request/connection_pools"
diff --git a/lib/rubygems/request/connection_pools.rb b/lib/rubygems/request/connection_pools.rb
index a4c2929b38..a283267674 100644
--- a/lib/rubygems/request/connection_pools.rb
+++ b/lib/rubygems/request/connection_pools.rb
@@ -37,7 +37,7 @@ class Gem::Request::ConnectionPools # :nodoc:
   # Returns list of no_proxy entries (if any) from the environment
 
   def get_no_proxy_from_env
-    env_no_proxy = ENV['no_proxy'] || ENV['NO_PROXY']
+    env_no_proxy = ENV["no_proxy"] || ENV["NO_PROXY"]
 
     return [] if env_no_proxy.nil? or env_no_proxy.empty?
 
@@ -45,7 +45,7 @@ class Gem::Request::ConnectionPools # :nodoc:
   end
 
   def https?(uri)
-    uri.scheme.downcase == 'https'
+    uri.scheme.downcase == "https"
   end
 
   def no_proxy?(host, env_no_proxy)
diff --git a/lib/rubygems/request_set.rb b/lib/rubygems/request_set.rb
index 01b01599a8..df215e4af3 100644
--- a/lib/rubygems/request_set.rb
+++ b/lib/rubygems/request_set.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative 'tsort'
+require_relative "tsort"
 
 ##
 # A RequestSet groups a request to activate a set of dependencies.
@@ -254,7 +254,7 @@ class Gem::RequestSet
   end
 
   def install_into(dir, force = true, options = {})
-    gem_home, ENV['GEM_HOME'] = ENV['GEM_HOME'], dir
+    gem_home, ENV["GEM_HOME"] = ENV["GEM_HOME"], dir
 
     existing = force ? [] : specs_in(dir)
     existing.delete_if {|s| @always_install.include? s }
@@ -287,7 +287,7 @@ class Gem::RequestSet
 
     installed
   ensure
-    ENV['GEM_HOME'] = gem_home
+    ENV["GEM_HOME"] = gem_home
   end
 
   ##
@@ -337,32 +337,32 @@ class Gem::RequestSet
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[RequestSet:', ']' do
+    q.group 2, "[RequestSet:", "]" do
       q.breakable
 
       if @remote
-        q.text 'remote'
+        q.text "remote"
         q.breakable
       end
 
       if @prerelease
-        q.text 'prerelease'
+        q.text "prerelease"
         q.breakable
       end
 
       if @development_shallow
-        q.text 'shallow development'
+        q.text "shallow development"
         q.breakable
       elsif @development
-        q.text 'development'
+        q.text "development"
         q.breakable
       end
 
       if @soft_missing
-        q.text 'soft missing'
+        q.text "soft missing"
       end
 
-      q.group 2, '[dependencies:', ']' do
+      q.group 2, "[dependencies:", "]" do
         q.breakable
         @dependencies.map do |dep|
           q.text dep.to_s
@@ -371,7 +371,7 @@ class Gem::RequestSet
       end
 
       q.breakable
-      q.text 'sets:'
+      q.text "sets:"
 
       q.breakable
       q.pp @sets.map {|set| set.class }
@@ -461,6 +461,6 @@ class Gem::RequestSet
   end
 end
 
-require_relative 'request_set/gem_dependency_api'
-require_relative 'request_set/lockfile'
-require_relative 'request_set/lockfile/tokenizer'
+require_relative "request_set/gem_dependency_api"
+require_relative "request_set/lockfile"
+require_relative "request_set/lockfile/tokenizer"
diff --git a/lib/rubygems/request_set/gem_dependency_api.rb b/lib/rubygems/request_set/gem_dependency_api.rb
index 7188b07346..568d9f952f 100644
--- a/lib/rubygems/request_set/gem_dependency_api.rb
+++ b/lib/rubygems/request_set/gem_dependency_api.rb
@@ -50,10 +50,10 @@ class Gem::RequestSet::GemDependencyAPI
     :ruby_21      => %w[ruby rbx maglev truffleruby],
   }.freeze
 
-  mswin     = Gem::Platform.new 'x86-mswin32'
-  mswin64   = Gem::Platform.new 'x64-mswin64'
-  x86_mingw = Gem::Platform.new 'x86-mingw32'
-  x64_mingw = Gem::Platform.new 'x64-mingw32'
+  mswin     = Gem::Platform.new "x86-mswin32"
+  mswin64   = Gem::Platform.new "x64-mswin64"
+  x86_mingw = Gem::Platform.new "x86-mingw32"
+  x64_mingw = Gem::Platform.new "x64-mingw32"
 
   PLATFORM_MAP = { # :nodoc:
     :jruby        => Gem::Platform::RUBY,
@@ -91,11 +91,11 @@ class Gem::RequestSet::GemDependencyAPI
     :x64_mingw_21 => x64_mingw,
   }.freeze
 
-  gt_eq_0        = Gem::Requirement.new '>= 0'
-  tilde_gt_1_8_0 = Gem::Requirement.new '~> 1.8.0'
-  tilde_gt_1_9_0 = Gem::Requirement.new '~> 1.9.0'
-  tilde_gt_2_0_0 = Gem::Requirement.new '~> 2.0.0'
-  tilde_gt_2_1_0 = Gem::Requirement.new '~> 2.1.0'
+  gt_eq_0        = Gem::Requirement.new ">= 0"
+  tilde_gt_1_8_0 = Gem::Requirement.new "~> 1.8.0"
+  tilde_gt_1_9_0 = Gem::Requirement.new "~> 1.9.0"
+  tilde_gt_2_0_0 = Gem::Requirement.new "~> 2.0.0"
+  tilde_gt_2_1_0 = Gem::Requirement.new "~> 2.1.0"
 
   VERSION_MAP = { # :nodoc:
     :jruby        => gt_eq_0,
@@ -435,7 +435,7 @@ Gem dependencies file #{@path} requires #{name} more than once.
     reference ||= ref
     reference ||= branch
     reference ||= tag
-    reference ||= 'master'
+    reference ||= "master"
 
     if ref && branch
       warn <<-WARNING
@@ -637,8 +637,8 @@ Gem dependencies file #{@path} includes git reference for both ref/branch and ta
   #   :development.  Only one group may be specified.
 
   def gemspec(options = {})
-    name              = options.delete(:name) || '{,*}'
-    path              = options.delete(:path) || '.'
+    name              = options.delete(:name) || "{,*}"
+    path              = options.delete(:path) || "."
     development_group = options.delete(:development_group) || :development
 
     spec = find_gemspec name, path
@@ -697,11 +697,11 @@ Gem dependencies file #{@path} includes git reference for both ref/branch and ta
   def pin_gem_source(name, type = :default, source = nil)
     source_description =
       case type
-      when :default then '(default)'
+      when :default then "(default)"
       when :path    then "path: #{source}"
       when :git     then "git: #{source}"
       when :source  then "source: #{source}"
-      else               '(unknown)'
+      else               "(unknown)"
       end
 
     raise ArgumentError,
@@ -788,7 +788,7 @@ Gem dependencies file #{@path} includes git reference for both ref/branch and ta
     engine_version = options[:engine_version]
 
     raise ArgumentError,
-          'You must specify engine_version along with the Ruby engine' if
+          "You must specify engine_version along with the Ruby engine" if
             engine and not engine_version
 
     return true if @installing
diff --git a/lib/rubygems/request_set/lockfile.rb b/lib/rubygems/request_set/lockfile.rb
index 684d3fc7fe..3ba202f661 100644
--- a/lib/rubygems/request_set/lockfile.rb
+++ b/lib/rubygems/request_set/lockfile.rb
@@ -76,7 +76,7 @@ class Gem::RequestSet::Lockfile
     @gem_deps_file = File.expand_path(gem_deps_file)
     @gem_deps_dir  = File.dirname(@gem_deps_file)
 
-    if RUBY_VERSION < '2.7'
+    if RUBY_VERSION < "2.7"
       @gem_deps_file.untaint unless gem_deps_file.tainted?
     end
 
@@ -106,7 +106,7 @@ class Gem::RequestSet::Lockfile
       out << "  specs:"
 
       requests.sort_by {|request| request.name }.each do |request|
-        next if request.spec.name == 'bundler'
+        next if request.spec.name == "bundler"
         platform = "-#{request.spec.platform}" unless
           Gem::Platform::RUBY == request.spec.platform
 
@@ -156,7 +156,7 @@ class Gem::RequestSet::Lockfile
     if dest.index(base) == 0
       offset = dest[base.size + 1..-1]
 
-      return '.' unless offset
+      return "." unless offset
 
       offset
     else
@@ -224,7 +224,7 @@ class Gem::RequestSet::Lockfile
   def write
     content = to_s
 
-    File.open "#{@gem_deps_file}.lock", 'w' do |io|
+    File.open "#{@gem_deps_file}.lock", "w" do |io|
       io.write content
     end
   end
@@ -236,4 +236,4 @@ class Gem::RequestSet::Lockfile
   end
 end
 
-require_relative 'lockfile/tokenizer'
+require_relative "lockfile/tokenizer"
diff --git a/lib/rubygems/request_set/lockfile/parser.rb b/lib/rubygems/request_set/lockfile/parser.rb
index 8c12b435af..376d37f9e2 100644
--- a/lib/rubygems/request_set/lockfile/parser.rb
+++ b/lib/rubygems/request_set/lockfile/parser.rb
@@ -19,15 +19,15 @@ class Gem::RequestSet::Lockfile::Parser
         @tokens.skip :newline
 
         case token.value
-        when 'DEPENDENCIES' then
+        when "DEPENDENCIES" then
           parse_DEPENDENCIES
-        when 'GIT' then
+        when "GIT" then
           parse_GIT
-        when 'GEM' then
+        when "GEM" then
           parse_GEM
-        when 'PATH' then
+        when "PATH" then
           parse_PATH
-        when 'PLATFORMS' then
+        when "PLATFORMS" then
           parse_PLATFORMS
         else
           token = get until @tokens.empty? or peek.first == :section
@@ -110,8 +110,8 @@ class Gem::RequestSet::Lockfile::Parser
   def parse_GEM # :nodoc:
     sources = []
 
-    while [:entry, 'remote'] == peek.first(2) do
-      get :entry, 'remote'
+    while [:entry, "remote"] == peek.first(2) do
+      get :entry, "remote"
       data = get(:text).value
       skip :newline
 
@@ -120,7 +120,7 @@ class Gem::RequestSet::Lockfile::Parser
 
     sources << Gem::Source.new(Gem::DEFAULT_HOST) if sources.empty?
 
-    get :entry, 'specs'
+    get :entry, "specs"
 
     skip :newline
 
@@ -145,7 +145,7 @@ class Gem::RequestSet::Lockfile::Parser
         data = token.value
 
         if type == :text and column == 4
-          version, platform = data.split '-', 2
+          version, platform = data.split "-", 2
 
           platform =
             platform ? Gem::Platform.new(platform) : Gem::Platform::RUBY
@@ -171,12 +171,12 @@ class Gem::RequestSet::Lockfile::Parser
   end
 
   def parse_GIT # :nodoc:
-    get :entry, 'remote'
+    get :entry, "remote"
     repository = get(:text).value
 
     skip :newline
 
-    get :entry, 'revision'
+    get :entry, "revision"
     revision = get(:text).value
 
     skip :newline
@@ -190,7 +190,7 @@ class Gem::RequestSet::Lockfile::Parser
       skip :newline
     end
 
-    get :entry, 'specs'
+    get :entry, "specs"
 
     skip :newline
 
@@ -234,12 +234,12 @@ class Gem::RequestSet::Lockfile::Parser
   end
 
   def parse_PATH # :nodoc:
-    get :entry, 'remote'
+    get :entry, "remote"
     directory = get(:text).value
 
     skip :newline
 
-    get :entry, 'specs'
+    get :entry, "specs"
 
     skip :newline
 
diff --git a/lib/rubygems/request_set/lockfile/tokenizer.rb b/lib/rubygems/request_set/lockfile/tokenizer.rb
index cb8030c143..79c573a02d 100644
--- a/lib/rubygems/request_set/lockfile/tokenizer.rb
+++ b/lib/rubygems/request_set/lockfile/tokenizer.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative 'parser'
+require_relative "parser"
 
 class Gem::RequestSet::Lockfile::Tokenizer
   Token = Struct.new :type, :value, :column, :line
@@ -57,7 +57,7 @@ class Gem::RequestSet::Lockfile::Tokenizer
   private
 
   def tokenize(input)
-    require 'strscan'
+    require "strscan"
     s = StringScanner.new input
 
     until s.eos? do
diff --git a/lib/rubygems/requirement.rb b/lib/rubygems/requirement.rb
index 9edd6aa7d3..12bf371f4e 100644
--- a/lib/rubygems/requirement.rb
+++ b/lib/rubygems/requirement.rb
@@ -61,7 +61,7 @@ class Gem::Requirement
       input
     when Gem::Version, Array then
       new input
-    when '!' then
+    when "!" then
       source_set
     else
       if input.respond_to? :to_str
@@ -73,11 +73,11 @@ class Gem::Requirement
   end
 
   def self.default
-    new '>= 0'
+    new ">= 0"
   end
 
   def self.default_prerelease
-    new '>= 0.a'
+    new ">= 0.a"
   end
 
   ###
@@ -218,7 +218,7 @@ class Gem::Requirement
   end
 
   def encode_with(coder) # :nodoc:
-    coder.add 'requirements', @requirements
+    coder.add "requirements", @requirements
   end
 
   ##
@@ -230,7 +230,7 @@ class Gem::Requirement
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 1, 'Gem::Requirement.new(', ')' do
+    q.group 1, "Gem::Requirement.new(", ")" do
       q.pp as_list
     end
   end
diff --git a/lib/rubygems/resolver.rb b/lib/rubygems/resolver.rb
index 51a11fed47..097e8243ee 100644
--- a/lib/rubygems/resolver.rb
+++ b/lib/rubygems/resolver.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
-require_relative 'dependency'
-require_relative 'exceptions'
-require_relative 'util/list'
+require_relative "dependency"
+require_relative "exceptions"
+require_relative "util/list"
 
 ##
 # Given a set of Gem::Dependency objects as +needed+ and a way to query the
@@ -10,14 +10,14 @@ require_relative 'util/list'
 # all the requirements.
 
 class Gem::Resolver
-  require_relative 'resolver/molinillo'
+  require_relative "resolver/molinillo"
 
   ##
   # If the DEBUG_RESOLVER environment variable is set then debugging mode is
   # enabled for the resolver.  This will display information about the state
   # of the resolver while a set of dependencies is being resolved.
 
-  DEBUG_RESOLVER = !ENV['DEBUG_RESOLVER'].nil?
+  DEBUG_RESOLVER = !ENV["DEBUG_RESOLVER"].nil?
 
   ##
   # Set to true if all development dependencies should be considered.
@@ -74,7 +74,7 @@ class Gem::Resolver
 
     case sets.length
     when 0 then
-      raise ArgumentError, 'one set in the composition must be non-nil'
+      raise ArgumentError, "one set in the composition must be non-nil"
     when 1 then
       sets.first
     else
@@ -124,7 +124,7 @@ class Gem::Resolver
     data = yield
     $stderr.printf "%10s (%d entries)\n", stage.to_s.upcase, data.size
     unless data.empty?
-      require 'pp'
+      require "pp"
       PP.pp data, $stderr
     end
   end
@@ -173,7 +173,7 @@ class Gem::Resolver
   include Molinillo::UI
 
   def output
-    @output ||= debug? ? $stdout : File.open(IO::NULL, 'w')
+    @output ||= debug? ? $stdout : File.open(IO::NULL, "w")
   end
 
   def debug?
@@ -318,30 +318,30 @@ class Gem::Resolver
   private :amount_constrained
 end
 
-require_relative 'resolver/activation_request'
-require_relative 'resolver/conflict'
-require_relative 'resolver/dependency_request'
-require_relative 'resolver/requirement_list'
-require_relative 'resolver/stats'
-
-require_relative 'resolver/set'
-require_relative 'resolver/api_set'
-require_relative 'resolver/composed_set'
-require_relative 'resolver/best_set'
-require_relative 'resolver/current_set'
-require_relative 'resolver/git_set'
-require_relative 'resolver/index_set'
-require_relative 'resolver/installer_set'
-require_relative 'resolver/lock_set'
-require_relative 'resolver/vendor_set'
-require_relative 'resolver/source_set'
-
-require_relative 'resolver/specification'
-require_relative 'resolver/spec_specification'
-require_relative 'resolver/api_specification'
-require_relative 'resolver/git_specification'
-require_relative 'resolver/index_specification'
-require_relative 'resolver/installed_specification'
-require_relative 'resolver/local_specification'
-require_relative 'resolver/lock_specification'
-require_relative 'resolver/vendor_specification'
+require_relative "resolver/activation_request"
+require_relative "resolver/conflict"
+require_relative "resolver/dependency_request"
+require_relative "resolver/requirement_list"
+require_relative "resolver/stats"
+
+require_relative "resolver/set"
+require_relative "resolver/api_set"
+require_relative "resolver/composed_set"
+require_relative "resolver/best_set"
+require_relative "resolver/current_set"
+require_relative "resolver/git_set"
+require_relative "resolver/index_set"
+require_relative "resolver/installer_set"
+require_relative "resolver/lock_set"
+require_relative "resolver/vendor_set"
+require_relative "resolver/source_set"
+
+require_relative "resolver/specification"
+require_relative "resolver/spec_specification"
+require_relative "resolver/api_specification"
+require_relative "resolver/git_specification"
+require_relative "resolver/index_specification"
+require_relative "resolver/installed_specification"
+require_relative "resolver/local_specification"
+require_relative "resolver/lock_specification"
+require_relative "resolver/vendor_specification"
diff --git a/lib/rubygems/resolver/activation_request.rb b/lib/rubygems/resolver/activation_request.rb
index ae35681db9..27877e0f4b 100644
--- a/lib/rubygems/resolver/activation_request.rb
+++ b/lib/rubygems/resolver/activation_request.rb
@@ -93,7 +93,7 @@ class Gem::Resolver::ActivationRequest
   end
 
   def inspect # :nodoc:
-    '#<%s for %p from %s>' % [
+    "#<%s for %p from %s>" % [
       self.class, @spec, @request
     ]
   end
@@ -130,12 +130,12 @@ class Gem::Resolver::ActivationRequest
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[Activation request', ']' do
+    q.group 2, "[Activation request", "]" do
       q.breakable
       q.pp @spec
 
       q.breakable
-      q.text ' for '
+      q.text " for "
       q.pp @request
     end
   end
diff --git a/lib/rubygems/resolver/api_set.rb b/lib/rubygems/resolver/api_set.rb
index 21c9b8920c..f2bef54a9c 100644
--- a/lib/rubygems/resolver/api_set.rb
+++ b/lib/rubygems/resolver/api_set.rb
@@ -26,13 +26,13 @@ class Gem::Resolver::APISet < Gem::Resolver::Set
   # API URL +dep_uri+ which is described at
   # https://guides.rubygems.org/rubygems-org-api
 
-  def initialize(dep_uri = 'https://index.rubygems.org/info/')
+  def initialize(dep_uri = "https://index.rubygems.org/info/")
     super()
 
     dep_uri = URI dep_uri unless URI === dep_uri
 
     @dep_uri = dep_uri
-    @uri     = dep_uri + '..'
+    @uri     = dep_uri + ".."
 
     @data   = Hash.new {|h,k| h[k] = [] }
     @source = Gem::Source.new @uri
@@ -83,12 +83,12 @@ class Gem::Resolver::APISet < Gem::Resolver::Set
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[APISet', ']' do
+    q.group 2, "[APISet", "]" do
       q.breakable
       q.text "URI: #{@dep_uri}"
 
       q.breakable
-      q.text 'gem names:'
+      q.text "gem names:"
       q.pp @data.keys
     end
   end
diff --git a/lib/rubygems/resolver/api_specification.rb b/lib/rubygems/resolver/api_specification.rb
index b5aa0b71d4..7af4d9cff3 100644
--- a/lib/rubygems/resolver/api_specification.rb
+++ b/lib/rubygems/resolver/api_specification.rb
@@ -62,7 +62,7 @@ class Gem::Resolver::APISpecification < Gem::Resolver::Specification
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[APISpecification', ']' do
+    q.group 2, "[APISpecification", "]" do
       q.breakable
       q.text "name: #{name}"
 
@@ -73,7 +73,7 @@ class Gem::Resolver::APISpecification < Gem::Resolver::Specification
       q.text "platform: #{platform}"
 
       q.breakable
-      q.text 'dependencies:'
+      q.text "dependencies:"
       q.breakable
       q.pp @dependencies
 
diff --git a/lib/rubygems/resolver/best_set.rb b/lib/rubygems/resolver/best_set.rb
index 300ea8015c..ab91ebca08 100644
--- a/lib/rubygems/resolver/best_set.rb
+++ b/lib/rubygems/resolver/best_set.rb
@@ -41,9 +41,9 @@ class Gem::Resolver::BestSet < Gem::Resolver::ComposedSet
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[BestSet', ']' do
+    q.group 2, "[BestSet", "]" do
       q.breakable
-      q.text 'sets:'
+      q.text "sets:"
 
       q.breakable
       q.pp @sets
diff --git a/lib/rubygems/resolver/conflict.rb b/lib/rubygems/resolver/conflict.rb
index 4c4588d7e8..54a7ca4641 100644
--- a/lib/rubygems/resolver/conflict.rb
+++ b/lib/rubygems/resolver/conflict.rb
@@ -65,7 +65,7 @@ class Gem::Resolver::Conflict
 
       matching = matching % [
         dependency,
-        alternates.join(', '),
+        alternates.join(", "),
       ]
     end
 
@@ -97,21 +97,21 @@ class Gem::Resolver::Conflict
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[Dependency conflict: ', ']' do
+    q.group 2, "[Dependency conflict: ", "]" do
       q.breakable
 
-      q.text 'activated '
+      q.text "activated "
       q.pp @activated
 
       q.breakable
-      q.text ' dependency '
+      q.text " dependency "
       q.pp @dependency
 
       q.breakable
       if @dependency == @failed_dep
-        q.text ' failed'
+        q.text " failed"
       else
-        q.text ' failed dependency '
+        q.text " failed dependency "
         q.pp @failed_dep
       end
     end
@@ -139,7 +139,7 @@ class Gem::Resolver::Conflict
       end
     end
 
-    path = ['user request (gem command or Gemfile)'] if path.empty?
+    path = ["user request (gem command or Gemfile)"] if path.empty?
 
     path
   end
diff --git a/lib/rubygems/resolver/dependency_request.rb b/lib/rubygems/resolver/dependency_request.rb
index 356aadb3b2..70a61cbc25 100644
--- a/lib/rubygems/resolver/dependency_request.rb
+++ b/lib/rubygems/resolver/dependency_request.rb
@@ -95,12 +95,12 @@ class Gem::Resolver::DependencyRequest
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[Dependency request ', ']' do
+    q.group 2, "[Dependency request ", "]" do
       q.breakable
       q.text @dependency.to_s
 
       q.breakable
-      q.text ' requested by '
+      q.text " requested by "
       q.pp @requester
     end
   end
diff --git a/lib/rubygems/resolver/git_set.rb b/lib/rubygems/resolver/git_set.rb
index eac51f15ad..f010273a8f 100644
--- a/lib/rubygems/resolver/git_set.rb
+++ b/lib/rubygems/resolver/git_set.rb
@@ -35,7 +35,7 @@ class Gem::Resolver::GitSet < Gem::Resolver::Set
   def initialize # :nodoc:
     super()
 
-    @git             = ENV['git'] || 'git'
+    @git             = ENV["git"] || "git"
     @need_submodules = {}
     @repositories    = {}
     @root_dir        = Gem.dir
@@ -104,7 +104,7 @@ class Gem::Resolver::GitSet < Gem::Resolver::Set
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[GitSet', ']' do
+    q.group 2, "[GitSet", "]" do
       next if @repositories.empty?
       q.breakable
 
diff --git a/lib/rubygems/resolver/git_specification.rb b/lib/rubygems/resolver/git_specification.rb
index ee47080ab4..d1e04737da 100644
--- a/lib/rubygems/resolver/git_specification.rb
+++ b/lib/rubygems/resolver/git_specification.rb
@@ -21,7 +21,7 @@ class Gem::Resolver::GitSpecification < Gem::Resolver::SpecSpecification
   # the executables.
 
   def install(options = {})
-    require_relative '../installer'
+    require_relative "../installer"
 
     installer = Gem::Installer.for_spec spec, options
 
@@ -35,7 +35,7 @@ class Gem::Resolver::GitSpecification < Gem::Resolver::SpecSpecification
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[GitSpecification', ']' do
+    q.group 2, "[GitSpecification", "]" do
       q.breakable
       q.text "name: #{name}"
 
@@ -43,7 +43,7 @@ class Gem::Resolver::GitSpecification < Gem::Resolver::SpecSpecification
       q.text "version: #{version}"
 
       q.breakable
-      q.text 'dependencies:'
+      q.text "dependencies:"
       q.breakable
       q.pp dependencies
 
diff --git a/lib/rubygems/resolver/index_set.rb b/lib/rubygems/resolver/index_set.rb
index 9390e34255..2344178314 100644
--- a/lib/rubygems/resolver/index_set.rb
+++ b/lib/rubygems/resolver/index_set.rb
@@ -53,14 +53,14 @@ class Gem::Resolver::IndexSet < Gem::Resolver::Set
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[IndexSet', ']' do
+    q.group 2, "[IndexSet", "]" do
       q.breakable
-      q.text 'sources:'
+      q.text "sources:"
       q.breakable
       q.pp @f.sources
 
       q.breakable
-      q.text 'specs:'
+      q.text "specs:"
 
       q.breakable
 
diff --git a/lib/rubygems/resolver/index_specification.rb b/lib/rubygems/resolver/index_specification.rb
index 9ea76f40ba..e8c3b35f7e 100644
--- a/lib/rubygems/resolver/index_specification.rb
+++ b/lib/rubygems/resolver/index_specification.rb
@@ -66,11 +66,11 @@ class Gem::Resolver::IndexSpecification < Gem::Resolver::Specification
   end
 
   def inspect # :nodoc:
-    '#<%s %s source %s>' % [self.class, full_name, @source]
+    "#<%s %s source %s>" % [self.class, full_name, @source]
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[Index specification', ']' do
+    q.group 2, "[Index specification", "]" do
       q.breakable
       q.text full_name
 
@@ -80,7 +80,7 @@ class Gem::Resolver::IndexSpecification < Gem::Resolver::Specification
       end
 
       q.breakable
-      q.text 'source '
+      q.text "source "
       q.pp @source
     end
   end
diff --git a/lib/rubygems/resolver/installed_specification.rb b/lib/rubygems/resolver/installed_specification.rb
index 167ba1439e..7c7ad8d85b 100644
--- a/lib/rubygems/resolver/installed_specification.rb
+++ b/lib/rubygems/resolver/installed_specification.rb
@@ -30,7 +30,7 @@ class Gem::Resolver::InstalledSpecification < Gem::Resolver::SpecSpecification
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[InstalledSpecification', ']' do
+    q.group 2, "[InstalledSpecification", "]" do
       q.breakable
       q.text "name: #{name}"
 
@@ -41,7 +41,7 @@ class Gem::Resolver::InstalledSpecification < Gem::Resolver::SpecSpecification
       q.text "platform: #{platform}"
 
       q.breakable
-      q.text 'dependencies:'
+      q.text "dependencies:"
       q.breakable
       q.pp spec.dependencies
     end
diff --git a/lib/rubygems/resolver/installer_set.rb b/lib/rubygems/resolver/installer_set.rb
index 45252ed241..15580d7095 100644
--- a/lib/rubygems/resolver/installer_set.rb
+++ b/lib/rubygems/resolver/installer_set.rb
@@ -190,7 +190,7 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
   def inspect # :nodoc:
     always_install = @always_install.map {|s| s.full_name }
 
-    '#<%s domain: %s specs: %p always install: %p>' % [
+    "#<%s domain: %s specs: %p always install: %p>" % [
       self.class, @domain, @specs.keys, always_install
     ]
   end
@@ -219,16 +219,16 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[InstallerSet', ']' do
+    q.group 2, "[InstallerSet", "]" do
       q.breakable
       q.text "domain: #{@domain}"
 
       q.breakable
-      q.text 'specs: '
+      q.text "specs: "
       q.pp @specs.keys
 
       q.breakable
-      q.text 'always install: '
+      q.text "always install: "
       q.pp @always_install
     end
   end
diff --git a/lib/rubygems/resolver/local_specification.rb b/lib/rubygems/resolver/local_specification.rb
index 9c69c4ab74..c27bab0f5a 100644
--- a/lib/rubygems/resolver/local_specification.rb
+++ b/lib/rubygems/resolver/local_specification.rb
@@ -17,7 +17,7 @@ class Gem::Resolver::LocalSpecification < Gem::Resolver::SpecSpecification
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[LocalSpecification', ']' do
+    q.group 2, "[LocalSpecification", "]" do
       q.breakable
       q.text "name: #{name}"
 
@@ -28,7 +28,7 @@ class Gem::Resolver::LocalSpecification < Gem::Resolver::SpecSpecification
       q.text "platform: #{platform}"
 
       q.breakable
-      q.text 'dependencies:'
+      q.text "dependencies:"
       q.breakable
       q.pp dependencies
 
diff --git a/lib/rubygems/resolver/lock_set.rb b/lib/rubygems/resolver/lock_set.rb
index eabf217aba..ff6c6c912f 100644
--- a/lib/rubygems/resolver/lock_set.rb
+++ b/lib/rubygems/resolver/lock_set.rb
@@ -63,15 +63,15 @@ class Gem::Resolver::LockSet < Gem::Resolver::Set
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[LockSet', ']' do
+    q.group 2, "[LockSet", "]" do
       q.breakable
-      q.text 'source:'
+      q.text "source:"
 
       q.breakable
       q.pp @source
 
       q.breakable
-      q.text 'specs:'
+      q.text "specs:"
 
       q.breakable
       q.pp @specs.map {|spec| spec.full_name }
diff --git a/lib/rubygems/resolver/lock_specification.rb b/lib/rubygems/resolver/lock_specification.rb
index cdb8e4e425..4a30dcf849 100644
--- a/lib/rubygems/resolver/lock_specification.rb
+++ b/lib/rubygems/resolver/lock_specification.rb
@@ -29,7 +29,7 @@ class Gem::Resolver::LockSpecification < Gem::Resolver::Specification
   def install(options = {})
     destination = options[:install_dir] || Gem.dir
 
-    if File.exist? File.join(destination, 'specifications', spec.spec_name)
+    if File.exist? File.join(destination, "specifications", spec.spec_name)
       yield nil
       return
     end
@@ -45,7 +45,7 @@ class Gem::Resolver::LockSpecification < Gem::Resolver::Specification
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[LockSpecification', ']' do
+    q.group 2, "[LockSpecification", "]" do
       q.breakable
       q.text "name: #{@name}"
 
@@ -59,7 +59,7 @@ class Gem::Resolver::LockSpecification < Gem::Resolver::Specification
 
       unless @dependencies.empty?
         q.breakable
-        q.text 'dependencies:'
+        q.text "dependencies:"
         q.breakable
         q.pp @dependencies
       end
diff --git a/lib/rubygems/resolver/molinillo.rb b/lib/rubygems/resolver/molinillo.rb
index 12ca740e5a..e154342571 100644
--- a/lib/rubygems/resolver/molinillo.rb
+++ b/lib/rubygems/resolver/molinillo.rb
@@ -1,2 +1,2 @@
 # frozen_string_literal: true
-require_relative 'molinillo/lib/molinillo'
+require_relative "molinillo/lib/molinillo"
diff --git a/lib/rubygems/resolver/specification.rb b/lib/rubygems/resolver/specification.rb
index dfcb7eb057..3da803cab5 100644
--- a/lib/rubygems/resolver/specification.rb
+++ b/lib/rubygems/resolver/specification.rb
@@ -93,7 +93,7 @@ class Gem::Resolver::Specification
   # specification.
 
   def install(options = {})
-    require_relative '../installer'
+    require_relative "../installer"
 
     gem = download options
 
diff --git a/lib/rubygems/resolver/vendor_set.rb b/lib/rubygems/resolver/vendor_set.rb
index 48c640d8c9..6c0ef2a1a1 100644
--- a/lib/rubygems/resolver/vendor_set.rb
+++ b/lib/rubygems/resolver/vendor_set.rb
@@ -69,7 +69,7 @@ class Gem::Resolver::VendorSet < Gem::Resolver::Set
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[VendorSet', ']' do
+    q.group 2, "[VendorSet", "]" do
       next if @directories.empty?
       q.breakable
 
diff --git a/lib/rubygems/s3_uri_signer.rb b/lib/rubygems/s3_uri_signer.rb
index 4d1deee997..5522753af5 100644
--- a/lib/rubygems/s3_uri_signer.rb
+++ b/lib/rubygems/s3_uri_signer.rb
@@ -1,4 +1,4 @@
-require_relative 'openssl'
+require_relative "openssl"
 
 ##
 # S3URISigner implements AWS SigV4 for S3 Source to avoid a dependency on the aws-sdk-* gems
@@ -138,14 +138,14 @@ class Gem::S3URISigner
   end
 
   def ec2_metadata_credentials_json
-    require 'net/http'
-    require_relative 'request'
-    require_relative 'request/connection_pools'
-    require 'json'
+    require "net/http"
+    require_relative "request"
+    require_relative "request/connection_pools"
+    require "json"
 
     iam_info = ec2_metadata_request(EC2_IAM_INFO)
     # Expected format: arn:aws:iam::<id>:instance-profile/<role_name>
-    role_name = iam_info['InstanceProfileArn'].split('/').last
+    role_name = iam_info["InstanceProfileArn"].split("/").last
     ec2_metadata_request(EC2_IAM_SECURITY_CREDENTIALS + role_name)
   end
 
diff --git a/lib/rubygems/safe_yaml.rb b/lib/rubygems/safe_yaml.rb
index 81f99ee26e..5a98505598 100644
--- a/lib/rubygems/safe_yaml.rb
+++ b/lib/rubygems/safe_yaml.rb
@@ -26,7 +26,7 @@ module Gem
 
     if ::Psych.respond_to? :safe_load
       def self.safe_load(input)
-        if Gem::Version.new(Psych::VERSION) >= Gem::Version.new('3.1.0.pre1')
+        if Gem::Version.new(Psych::VERSION) >= Gem::Version.new("3.1.0.pre1")
           ::Psych.safe_load(input, permitted_classes: PERMITTED_CLASSES, permitted_symbols: PERMITTED_SYMBOLS, aliases: true)
         else
           ::Psych.safe_load(input, PERMITTED_CLASSES, PERMITTED_SYMBOLS, true)
@@ -34,7 +34,7 @@ module Gem
       end
 
       def self.load(input)
-        if Gem::Version.new(Psych::VERSION) >= Gem::Version.new('3.1.0.pre1')
+        if Gem::Version.new(Psych::VERSION) >= Gem::Version.new("3.1.0.pre1")
           ::Psych.safe_load(input, permitted_classes: [::Symbol])
         else
           ::Psych.safe_load(input, [::Symbol])
diff --git a/lib/rubygems/security.rb b/lib/rubygems/security.rb
index fc23c1c481..4eb4023055 100644
--- a/lib/rubygems/security.rb
+++ b/lib/rubygems/security.rb
@@ -5,8 +5,8 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'exceptions'
-require_relative 'openssl'
+require_relative "exceptions"
+require_relative "openssl"
 
 ##
 # = Signing gems
@@ -334,7 +334,7 @@ module Gem::Security
   ##
   # Used internally to select the signing digest from all computed digests
 
-  DIGEST_NAME = 'SHA256' # :nodoc:
+  DIGEST_NAME = "SHA256" # :nodoc:
 
   ##
   # Length of keys created by RSA and DSA keys
@@ -344,18 +344,18 @@ module Gem::Security
   ##
   # Default algorithm to use when building a key pair
 
-  DEFAULT_KEY_ALGORITHM = 'RSA'
+  DEFAULT_KEY_ALGORITHM = "RSA"
 
   ##
   # Named curve used for Elliptic Curve
 
-  EC_NAME = 'secp384r1'
+  EC_NAME = "secp384r1"
 
   ##
   # Cipher used to encrypt the key pair used to sign gems.
   # Must be in the list returned by OpenSSL::Cipher.ciphers
 
-  KEY_CIPHER = OpenSSL::Cipher.new('AES-256-CBC') if defined?(OpenSSL::Cipher)
+  KEY_CIPHER = OpenSSL::Cipher.new("AES-256-CBC") if defined?(OpenSSL::Cipher)
 
   ##
   # One day in seconds
@@ -376,10 +376,10 @@ module Gem::Security
   # * The certificate contains a subject key identifier
 
   EXTENSIONS = {
-    'basicConstraints'     => 'CA:FALSE',
-    'keyUsage'             =>
-      'keyEncipherment,dataEncipherment,digitalSignature',
-    'subjectKeyIdentifier' => 'hash',
+    "basicConstraints"     => "CA:FALSE",
+    "keyUsage"             =>
+      "keyEncipherment,dataEncipherment,digitalSignature",
+    "subjectKeyIdentifier" => "hash",
   }.freeze
 
   def self.alt_name_or_x509_entry(certificate, x509_entry)
@@ -473,7 +473,7 @@ module Gem::Security
       OpenSSL::Digest.new(algorithm)
     end
   else
-    require 'digest'
+    require "digest"
 
     def self.create_digest(algorithm = DIGEST_NAME)
       Digest.const_get(algorithm).new
@@ -487,11 +487,11 @@ module Gem::Security
   def self.create_key(algorithm)
     if defined?(OpenSSL::PKey)
       case algorithm.downcase
-      when 'dsa'
+      when "dsa"
         OpenSSL::PKey::DSA.new(RSA_DSA_KEY_LENGTH)
-      when 'rsa'
+      when "rsa"
         OpenSSL::PKey::RSA.new(RSA_DSA_KEY_LENGTH)
-      when 'ec'
+      when "ec"
         if RUBY_VERSION >= "2.4.0"
           OpenSSL::PKey::EC.generate(EC_NAME)
         else
@@ -510,11 +510,11 @@ module Gem::Security
   # Turns +email_address+ into an OpenSSL::X509::Name
 
   def self.email_to_name(email_address)
-    email_address = email_address.gsub(/[^\w@.-]+/i, '_')
+    email_address = email_address.gsub(/[^\w@.-]+/i, "_")
 
-    cn, dcs = email_address.split '@'
+    cn, dcs = email_address.split "@"
 
-    dcs = dcs.split '.'
+    dcs = dcs.split "."
 
     OpenSSL::X509::Name.new([
       ["CN", cn],
@@ -571,17 +571,17 @@ module Gem::Security
     signee_key     = certificate.public_key
 
     alt_name = certificate.extensions.find do |extension|
-      extension.oid == 'subjectAltName'
+      extension.oid == "subjectAltName"
     end
 
-    extensions = extensions.merge 'subjectAltName' => alt_name.value if
+    extensions = extensions.merge "subjectAltName" => alt_name.value if
       alt_name
 
     issuer_alt_name = signing_cert.extensions.find do |extension|
-      extension.oid == 'subjectAltName'
+      extension.oid == "subjectAltName"
     end
 
-    extensions = extensions.merge 'issuerAltName' => issuer_alt_name.value if
+    extensions = extensions.merge "issuerAltName" => issuer_alt_name.value if
       issuer_alt_name
 
     signed = create_cert signee_subject, signee_key, age, extensions, serial
@@ -597,7 +597,7 @@ module Gem::Security
   def self.trust_dir
     return @trust_dir if @trust_dir
 
-    dir = File.join Gem.user_home, '.gem', 'trust'
+    dir = File.join Gem.user_home, ".gem", "trust"
 
     @trust_dir ||= Gem::Security::TrustDir.new dir
   end
@@ -617,7 +617,7 @@ module Gem::Security
   def self.write(pemmable, path, permissions = 0600, passphrase = nil, cipher = KEY_CIPHER)
     path = File.expand_path path
 
-    File.open path, 'wb', permissions do |io|
+    File.open path, "wb", permissions do |io|
       if passphrase and cipher
         io.write pemmable.to_pem cipher, passphrase
       else
@@ -633,9 +633,9 @@ module Gem::Security
 end
 
 if Gem::HAVE_OPENSSL
-  require_relative 'security/policy'
-  require_relative 'security/policies'
-  require_relative 'security/trust_dir'
+  require_relative "security/policy"
+  require_relative "security/policies"
+  require_relative "security/trust_dir"
 end
 
-require_relative 'security/signer'
+require_relative "security/signer"
diff --git a/lib/rubygems/security/policies.rb b/lib/rubygems/security/policies.rb
index 8f6ad99316..b3f9070394 100644
--- a/lib/rubygems/security/policies.rb
+++ b/lib/rubygems/security/policies.rb
@@ -5,7 +5,7 @@ module Gem::Security
   # No security policy: all package signature checks are disabled.
 
   NoSecurity = Policy.new(
-    'No Security',
+    "No Security",
     :verify_data      => false,
     :verify_signer    => false,
     :verify_chain     => false,
@@ -23,7 +23,7 @@ module Gem::Security
   # easily spoofed, and is not recommended.
 
   AlmostNoSecurity = Policy.new(
-    'Almost No Security',
+    "Almost No Security",
     :verify_data      => true,
     :verify_signer    => false,
     :verify_chain     => false,
@@ -40,7 +40,7 @@ module Gem::Security
   # is not recommended.
 
   LowSecurity = Policy.new(
-    'Low Security',
+    "Low Security",
     :verify_data      => true,
     :verify_signer    => true,
     :verify_chain     => false,
@@ -59,7 +59,7 @@ module Gem::Security
   # gem off as unsigned.
 
   MediumSecurity = Policy.new(
-    'Medium Security',
+    "Medium Security",
     :verify_data      => true,
     :verify_signer    => true,
     :verify_chain     => true,
@@ -78,7 +78,7 @@ module Gem::Security
   # a reasonable guarantee that the contents of the gem have not been altered.
 
   HighSecurity = Policy.new(
-    'High Security',
+    "High Security",
     :verify_data      => true,
     :verify_signer    => true,
     :verify_chain     => true,
@@ -91,7 +91,7 @@ module Gem::Security
   # Policy used to verify a certificate and key when signing a gem
 
   SigningPolicy = Policy.new(
-    'Signing Policy',
+    "Signing Policy",
     :verify_data      => false,
     :verify_signer    => true,
     :verify_chain     => true,
@@ -104,11 +104,11 @@ module Gem::Security
   # Hash of configured security policies
 
   Policies = {
-    'NoSecurity'       => NoSecurity,
-    'AlmostNoSecurity' => AlmostNoSecurity,
-    'LowSecurity'      => LowSecurity,
-    'MediumSecurity'   => MediumSecurity,
-    'HighSecurity'     => HighSecurity,
+    "NoSecurity"       => NoSecurity,
+    "AlmostNoSecurity" => AlmostNoSecurity,
+    "LowSecurity"      => LowSecurity,
+    "MediumSecurity"   => MediumSecurity,
+    "HighSecurity"     => HighSecurity,
     # SigningPolicy is not intended for use by `gem -P` so do not list it
   }.freeze
 
diff --git a/lib/rubygems/security/policy.rb b/lib/rubygems/security/policy.rb
index 06eae073f4..43588fd7f1 100644
--- a/lib/rubygems/security/policy.rb
+++ b/lib/rubygems/security/policy.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative '../user_interaction'
+require_relative "../user_interaction"
 
 ##
 # A Gem::Security::Policy object encapsulates the settings for verifying
@@ -53,8 +53,8 @@ class Gem::Security::Policy
   # and is valid for the given +time+.
 
   def check_chain(chain, time)
-    raise Gem::Security::Exception, 'missing signing chain' unless chain
-    raise Gem::Security::Exception, 'empty signing chain' if chain.empty?
+    raise Gem::Security::Exception, "missing signing chain" unless chain
+    raise Gem::Security::Exception, "empty signing chain" if chain.empty?
 
     begin
       chain.each_cons 2 do |issuer, cert|
@@ -83,7 +83,7 @@ class Gem::Security::Policy
   # If the +issuer+ is +nil+ no verification is performed.
 
   def check_cert(signer, issuer, time)
-    raise Gem::Security::Exception, 'missing signing certificate' unless
+    raise Gem::Security::Exception, "missing signing certificate" unless
       signer
 
     message = "certificate #{signer.subject}"
@@ -112,7 +112,7 @@ class Gem::Security::Policy
     unless signer and key
       return true unless @only_signed
 
-      raise Gem::Security::Exception, 'missing key or signature'
+      raise Gem::Security::Exception, "missing key or signature"
     end
 
     raise Gem::Security::Exception,
@@ -127,11 +127,11 @@ class Gem::Security::Policy
   # +time+.
 
   def check_root(chain, time)
-    raise Gem::Security::Exception, 'missing signing chain' unless chain
+    raise Gem::Security::Exception, "missing signing chain" unless chain
 
     root = chain.first
 
-    raise Gem::Security::Exception, 'missing root certificate' unless root
+    raise Gem::Security::Exception, "missing root certificate" unless root
 
     raise Gem::Security::Exception,
           "root certificate #{root.subject} is not self-signed " +
@@ -146,11 +146,11 @@ class Gem::Security::Policy
   # the digests of the two certificates match according to +digester+
 
   def check_trust(chain, digester, trust_dir)
-    raise Gem::Security::Exception, 'missing signing chain' unless chain
+    raise Gem::Security::Exception, "missing signing chain" unless chain
 
     root = chain.first
 
-    raise Gem::Security::Exception, 'missing root certificate' unless root
+    raise Gem::Security::Exception, "missing root certificate" unless root
 
     path = Gem::Security.trust_dir.cert_path root
 
@@ -182,7 +182,7 @@ class Gem::Security::Policy
 
   def subject(certificate) # :nodoc:
     certificate.extensions.each do |extension|
-      next unless extension.oid == 'subjectAltName'
+      next unless extension.oid == "subjectAltName"
 
       return extension.value
     end
@@ -206,7 +206,7 @@ class Gem::Security::Policy
   # If +key+ is given it is used to validate the signing certificate.
 
   def verify(chain, key = nil, digests = {}, signatures = {},
-             full_name = '(unknown)')
+             full_name = "(unknown)")
     if signatures.empty?
       if @only_signed
         raise Gem::Security::Exception,
@@ -230,7 +230,7 @@ class Gem::Security::Policy
     end
 
     if @verify_data
-      raise Gem::Security::Exception, 'no digests provided (probable bug)' if
+      raise Gem::Security::Exception, "no digests provided (probable bug)" if
         signer_digests.nil? or signer_digests.empty?
     else
       signer_digests = {}
diff --git a/lib/rubygems/security/signer.rb b/lib/rubygems/security/signer.rb
index 968cf88973..b1308c4e42 100644
--- a/lib/rubygems/security/signer.rb
+++ b/lib/rubygems/security/signer.rb
@@ -42,7 +42,7 @@ class Gem::Security::Signer
   def self.re_sign_cert(expired_cert, expired_cert_path, private_key)
     return unless expired_cert.not_after < Time.now
 
-    expiry = expired_cert.not_after.strftime('%Y%m%d%H%M%S')
+    expiry = expired_cert.not_after.strftime("%Y%m%d%H%M%S")
     expired_cert_file = "#{File.basename(expired_cert_path)}.expired.#{expiry}"
     new_expired_cert_path = File.join(Gem.user_home, ".gem", expired_cert_file)
 
@@ -105,7 +105,7 @@ class Gem::Security::Signer
   # this value is preferred, otherwise the subject is used.
 
   def extract_name(cert) # :nodoc:
-    subject_alt_name = cert.extensions.find {|e| 'subjectAltName' == e.oid }
+    subject_alt_name = cert.extensions.find {|e| "subjectAltName" == e.oid }
 
     if subject_alt_name
       /\Aemail:/ =~ subject_alt_name.value # rubocop:disable Performance/StartWith
@@ -139,7 +139,7 @@ class Gem::Security::Signer
   def sign(data)
     return unless @key
 
-    raise Gem::Security::Exception, 'no certs provided' if @cert_chain.empty?
+    raise Gem::Security::Exception, "no certs provided" if @cert_chain.empty?
 
     if @cert_chain.length == 1 and @cert_chain.last.not_after < Time.now
       alert("Your certificate has expired, trying to re-sign it...")
@@ -182,7 +182,7 @@ class Gem::Security::Signer
     return unless disk_key
 
     if disk_key.to_pem == @key.to_pem && disk_cert == old_cert.to_pem
-      expiry = old_cert.not_after.strftime('%Y%m%d%H%M%S')
+      expiry = old_cert.not_after.strftime("%Y%m%d%H%M%S")
       old_cert_file = "gem-public_cert.pem.expired.#{expiry}"
       old_cert_path = File.join(Gem.user_home, ".gem", old_cert_file)
 
diff --git a/lib/rubygems/security/trust_dir.rb b/lib/rubygems/security/trust_dir.rb
index 456947274c..a6882c66e7 100644
--- a/lib/rubygems/security/trust_dir.rb
+++ b/lib/rubygems/security/trust_dir.rb
@@ -41,7 +41,7 @@ class Gem::Security::TrustDir
   def each_certificate
     return enum_for __method__ unless block_given?
 
-    glob = File.join @dir, '*.pem'
+    glob = File.join @dir, "*.pem"
 
     Dir[glob].each do |certificate_file|
       begin
@@ -92,7 +92,7 @@ class Gem::Security::TrustDir
 
     destination = cert_path certificate
 
-    File.open destination, 'wb', 0600 do |io|
+    File.open destination, "wb", 0600 do |io|
       io.write certificate.to_pem
       io.chmod(@permissions[:trusted_cert])
     end
@@ -104,7 +104,7 @@ class Gem::Security::TrustDir
   # permissions.
 
   def verify
-    require 'fileutils'
+    require "fileutils"
     if File.exist? @dir
       raise Gem::Security::Exception,
         "trust directory #{@dir} is not a directory" unless
diff --git a/lib/rubygems/security_option.rb b/lib/rubygems/security_option.rb
index a4c570ded5..ab3898bf11 100644
--- a/lib/rubygems/security_option.rb
+++ b/lib/rubygems/security_option.rb
@@ -5,7 +5,7 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative '../rubygems'
+require_relative "../rubygems"
 
 # forward-declare
 
@@ -20,9 +20,9 @@ end
 module Gem::SecurityOption
   def add_security_option
     Gem::OptionParser.accept Gem::Security::Policy do |value|
-      require_relative 'security'
+      require_relative "security"
 
-      raise Gem::OptionParser::InvalidArgument, 'OpenSSL not installed' unless
+      raise Gem::OptionParser::InvalidArgument, "OpenSSL not installed" unless
         defined?(Gem::Security::HighSecurity)
 
       policy = Gem::Security::Policies[value]
@@ -33,9 +33,9 @@ module Gem::SecurityOption
       policy
     end
 
-    add_option(:"Install/Update", '-P', '--trust-policy POLICY',
+    add_option(:"Install/Update", "-P", "--trust-policy POLICY",
                Gem::Security::Policy,
-               'Specify gem trust policy') do |value, options|
+               "Specify gem trust policy") do |value, options|
       options[:security_policy] = value
     end
   end
diff --git a/lib/rubygems/source.rb b/lib/rubygems/source.rb
index 5f49a0d216..7c3b678645 100644
--- a/lib/rubygems/source.rb
+++ b/lib/rubygems/source.rb
@@ -12,9 +12,9 @@ class Gem::Source
   include Gem::Text
 
   FILES = { # :nodoc:
-    :released   => 'specs',
-    :latest     => 'latest_specs',
-    :prerelease => 'prerelease_specs',
+    :released   => "specs",
+    :latest     => "latest_specs",
+    :prerelease => "prerelease_specs",
   }.freeze
 
   ##
@@ -71,7 +71,7 @@ class Gem::Source
   # Returns a Set that can fetch specifications from this source.
 
   def dependency_resolver_set # :nodoc:
-    return Gem::Resolver::IndexSet.new self if 'file' == uri.scheme
+    return Gem::Resolver::IndexSet.new self if "file" == uri.scheme
 
     fetch_uri = if uri.host == "rubygems.org"
       index_uri = uri.dup
@@ -141,7 +141,7 @@ class Gem::Source
       return spec if spec
     end
 
-    source_uri.path << '.rz'
+    source_uri.path << ".rz"
 
     spec = fetcher.fetch_path source_uri
     spec = Gem::Util.inflate spec
@@ -150,7 +150,7 @@ class Gem::Source
       require "fileutils"
       FileUtils.mkdir_p cache_dir
 
-      File.open local_spec, 'wb' do |io|
+      File.open local_spec, "wb" do |io|
         io.write spec
       end
     end
@@ -209,13 +209,13 @@ class Gem::Source
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[Remote:', ']' do
+    q.group 2, "[Remote:", "]" do
       q.breakable
       q.text @uri.to_s
 
       if api = uri
         q.breakable
-        q.text 'API URI: '
+        q.text "API URI: "
         q.text api.to_s
       end
     end
@@ -229,13 +229,13 @@ class Gem::Source
   private
 
   def enforce_trailing_slash(uri)
-    uri.merge(uri.path.gsub(/\/+$/, '') + '/')
+    uri.merge(uri.path.gsub(/\/+$/, "") + "/")
   end
 end
 
-require_relative 'source/git'
-require_relative 'source/installed'
-require_relative 'source/specific_file'
-require_relative 'source/local'
-require_relative 'source/lock'
-require_relative 'source/vendor'
+require_relative "source/git"
+require_relative "source/installed"
+require_relative "source/specific_file"
+require_relative "source/local"
+require_relative "source/lock"
+require_relative "source/vendor"
diff --git a/lib/rubygems/source/git.rb b/lib/rubygems/source/git.rb
index 1d964eb59a..22355adcfa 100644
--- a/lib/rubygems/source/git.rb
+++ b/lib/rubygems/source/git.rb
@@ -58,7 +58,7 @@ class Gem::Source::Git < Gem::Source
 
     @remote   = true
     @root_dir = Gem.dir
-    @git      = ENV['git'] || 'git'
+    @git      = ENV["git"] || "git"
   end
 
   def <=>(other)
@@ -92,18 +92,18 @@ class Gem::Source::Git < Gem::Source
     return false unless File.exist? repo_cache_dir
 
     unless File.exist? install_dir
-      system @git, 'clone', '--quiet', '--no-checkout',
+      system @git, "clone", "--quiet", "--no-checkout",
              repo_cache_dir, install_dir
     end
 
     Dir.chdir install_dir do
-      system @git, 'fetch', '--quiet', '--force', '--tags', install_dir
+      system @git, "fetch", "--quiet", "--force", "--tags", install_dir
 
-      success = system @git, 'reset', '--quiet', '--hard', rev_parse
+      success = system @git, "reset", "--quiet", "--hard", rev_parse
 
       if @need_submodules
         require "open3"
-        _, status = Open3.capture2e(@git, 'submodule', 'update', '--quiet', '--init', '--recursive')
+        _, status = Open3.capture2e(@git, "submodule", "update", "--quiet", "--init", "--recursive")
 
         success &&= status.success?
       end
@@ -120,11 +120,11 @@ class Gem::Source::Git < Gem::Source
 
     if File.exist? repo_cache_dir
       Dir.chdir repo_cache_dir do
-        system @git, 'fetch', '--quiet', '--force', '--tags',
-               @repository, 'refs/heads/*:refs/heads/*'
+        system @git, "fetch", "--quiet", "--force", "--tags",
+               @repository, "refs/heads/*:refs/heads/*"
       end
     else
-      system @git, 'clone', '--quiet', '--bare', '--no-hardlinks',
+      system @git, "clone", "--quiet", "--bare", "--no-hardlinks",
              @repository, repo_cache_dir
     end
   end
@@ -133,7 +133,7 @@ class Gem::Source::Git < Gem::Source
   # Directory where git gems get unpacked and so-forth.
 
   def base_dir # :nodoc:
-    File.join @root_dir, 'bundler'
+    File.join @root_dir, "bundler"
   end
 
   ##
@@ -155,11 +155,11 @@ class Gem::Source::Git < Gem::Source
   def install_dir # :nodoc:
     return unless File.exist? repo_cache_dir
 
-    File.join base_dir, 'gems', "#{@name}-#{dir_shortref}"
+    File.join base_dir, "gems", "#{@name}-#{dir_shortref}"
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[Git: ', ']' do
+    q.group 2, "[Git: ", "]" do
       q.breakable
       q.text @repository
 
@@ -172,7 +172,7 @@ class Gem::Source::Git < Gem::Source
   # The directory where the git gem's repository will be cached.
 
   def repo_cache_dir # :nodoc:
-    File.join @root_dir, 'cache', 'bundler', 'git', "#{@name}-#{uri_hash}"
+    File.join @root_dir, "cache", "bundler", "git", "#{@name}-#{uri_hash}"
   end
 
   ##
@@ -182,7 +182,7 @@ class Gem::Source::Git < Gem::Source
     hash = nil
 
     Dir.chdir repo_cache_dir do
-      hash = Gem::Util.popen(@git, 'rev-parse', @reference).strip
+      hash = Gem::Util.popen(@git, "rev-parse", @reference).strip
     end
 
     raise Gem::Exception,
@@ -201,7 +201,7 @@ class Gem::Source::Git < Gem::Source
     return [] unless install_dir
 
     Dir.chdir install_dir do
-      Dir['{,*,*/*}.gemspec'].map do |spec_file|
+      Dir["{,*,*/*}.gemspec"].map do |spec_file|
         directory = File.dirname spec_file
         file      = File.basename spec_file
 
@@ -211,7 +211,7 @@ class Gem::Source::Git < Gem::Source
             spec.base_dir = base_dir
 
             spec.extension_dir =
-              File.join base_dir, 'extensions', Gem::Platform.local.to_s,
+              File.join base_dir, "extensions", Gem::Platform.local.to_s,
                 Gem.extension_api_version, "#{name}-#{dir_shortref}"
 
             spec.full_gem_path = File.dirname spec.loaded_from if spec
@@ -226,11 +226,11 @@ class Gem::Source::Git < Gem::Source
   # A hash for the git gem based on the git repository URI.
 
   def uri_hash # :nodoc:
-    require_relative '../openssl'
+    require_relative "../openssl"
 
     normalized =
       if @repository =~ %r{^\w+://(\w+@)?}
-        uri = URI(@repository).normalize.to_s.sub %r{/$},''
+        uri = URI(@repository).normalize.to_s.sub %r{/$},""
         uri.sub(/\A(\w+)/) { $1.downcase }
       else
         @repository
diff --git a/lib/rubygems/source/installed.rb b/lib/rubygems/source/installed.rb
index 7e1dd7af5a..786faab3e3 100644
--- a/lib/rubygems/source/installed.rb
+++ b/lib/rubygems/source/installed.rb
@@ -33,6 +33,6 @@ class Gem::Source::Installed < Gem::Source
   end
 
   def pretty_print(q) # :nodoc:
-    q.text '[Installed]'
+    q.text "[Installed]"
   end
 end
diff --git a/lib/rubygems/source/local.rb b/lib/rubygems/source/local.rb
index 078b06203f..ec1a594238 100644
--- a/lib/rubygems/source/local.rb
+++ b/lib/rubygems/source/local.rb
@@ -29,7 +29,7 @@ class Gem::Source::Local < Gem::Source
   end
 
   def inspect # :nodoc:
-    keys = @specs ? @specs.keys.sort : 'NOT LOADED'
+    keys = @specs ? @specs.keys.sort : "NOT LOADED"
     "#<%s specs: %p>" % [self.class, keys]
   end
 
@@ -121,7 +121,7 @@ class Gem::Source::Local < Gem::Source
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[Local gems:', ']' do
+    q.group 2, "[Local gems:", "]" do
       q.breakable
       q.seplist @specs.keys do |v|
         q.text v.full_name
diff --git a/lib/rubygems/source/specific_file.rb b/lib/rubygems/source/specific_file.rb
index 24db1440dd..552aeba50f 100644
--- a/lib/rubygems/source/specific_file.rb
+++ b/lib/rubygems/source/specific_file.rb
@@ -42,7 +42,7 @@ class Gem::Source::SpecificFile < Gem::Source
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, '[SpecificFile:', ']' do
+    q.group 2, "[SpecificFile:", "]" do
       q.breakable
       q.text @path
     end
diff --git a/lib/rubygems/spec_fetcher.rb b/lib/rubygems/spec_fetcher.rb
index 4033e2efa3..43e7e05b63 100644
--- a/lib/rubygems/spec_fetcher.rb
+++ b/lib/rubygems/spec_fetcher.rb
@@ -1,9 +1,9 @@
 # frozen_string_literal: true
-require_relative 'remote_fetcher'
-require_relative 'user_interaction'
-require_relative 'errors'
-require_relative 'text'
-require_relative 'name_tuple'
+require_relative "remote_fetcher"
+require_relative "user_interaction"
+require_relative "errors"
+require_relative "text"
+require_relative "name_tuple"
 
 ##
 # SpecFetcher handles metadata updates from remote gem repositories.
@@ -171,19 +171,19 @@ class Gem::SpecFetcher
   # alternative gem names.
 
   def suggest_gems_from_name(gem_name, type = :latest, num_results = 5)
-    gem_name        = gem_name.downcase.tr('_-', '')
+    gem_name        = gem_name.downcase.tr("_-", "")
     max             = gem_name.size / 2
     names           = available_specs(type).first.values.flatten(1)
 
     matches = names.map do |n|
       next unless n.match_platform?
-      [n.name, 0] if n.name.downcase.tr('_-', '').include?(gem_name)
+      [n.name, 0] if n.name.downcase.tr("_-", "").include?(gem_name)
     end.compact
 
     if matches.length < num_results
       matches += names.map do |n|
         next unless n.match_platform?
-        distance = levenshtein_distance gem_name, n.name.downcase.tr('_-', '')
+        distance = levenshtein_distance gem_name, n.name.downcase.tr("_-", "")
         next if distance >= max
         return [n.name] if distance == 0
         [n.name, distance]
diff --git a/lib/rubygems/specification.rb b/lib/rubygems/specification.rb
index a8e52e58d5..f2e2740026 100644
--- a/lib/rubygems/specification.rb
+++ b/lib/rubygems/specification.rb
@@ -6,11 +6,11 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'deprecate'
-require_relative 'basic_specification'
-require_relative 'stub_specification'
-require_relative 'platform'
-require_relative 'util/list'
+require_relative "deprecate"
+require_relative "basic_specification"
+require_relative "stub_specification"
+require_relative "platform"
+require_relative "util/list"
 
 ##
 # The Specification class contains the information for a gem.  Typically
@@ -74,20 +74,20 @@ class Gem::Specification < Gem::BasicSpecification
   # key should be equal to the CURRENT_SPECIFICATION_VERSION.
 
   SPECIFICATION_VERSION_HISTORY = { # :nodoc:
-    -1 => ['(RubyGems versions up to and including 0.7 did not have versioned specifications)'],
+    -1 => ["(RubyGems versions up to and including 0.7 did not have versioned specifications)"],
     1  => [
       'Deprecated "test_suite_file" in favor of the new, but equivalent, "test_files"',
       '"test_file=x" is a shortcut for "test_files=[x]"',
     ],
     2 => [
       'Added "required_rubygems_version"',
-      'Now forward-compatible with future versions',
+      "Now forward-compatible with future versions",
     ],
     3 => [
-      'Added Fixnum validation to the specification_version',
+      "Added Fixnum validation to the specification_version",
     ],
     4 => [
-      'Added sandboxed freeform metadata to the specification version.',
+      "Added sandboxed freeform metadata to the specification version.",
     ],
   }.freeze
 
@@ -126,7 +126,7 @@ class Gem::Specification < Gem::BasicSpecification
   @@default_value = {
     :authors                   => [],
     :autorequire               => nil,
-    :bindir                    => 'bin',
+    :bindir                    => "bin",
     :cert_chain                => [],
     :date                      => nil,
     :dependencies              => [],
@@ -143,7 +143,7 @@ class Gem::Specification < Gem::BasicSpecification
     :platform                  => Gem::Platform::RUBY,
     :post_install_message      => nil,
     :rdoc_options              => [],
-    :require_paths             => ['lib'],
+    :require_paths             => ["lib"],
     :required_ruby_version     => Gem::Requirement.default,
     :required_rubygems_version => Gem::Requirement.default,
     :requirements              => [],
@@ -489,12 +489,12 @@ class Gem::Specification < Gem::BasicSpecification
     # legacy constants
     when nil, Gem::Platform::RUBY then
       @new_platform = Gem::Platform::RUBY
-    when 'mswin32' then # was Gem::Platform::WIN32
-      @new_platform = Gem::Platform.new 'x86-mswin32'
-    when 'i586-linux' then # was Gem::Platform::LINUX_586
-      @new_platform = Gem::Platform.new 'x86-linux'
-    when 'powerpc-darwin' then # was Gem::Platform::DARWIN
-      @new_platform = Gem::Platform.new 'ppc-darwin'
+    when "mswin32" then # was Gem::Platform::WIN32
+      @new_platform = Gem::Platform.new "x86-mswin32"
+    when "i586-linux" then # was Gem::Platform::LINUX_586
+      @new_platform = Gem::Platform.new "x86-linux"
+    when "powerpc-darwin" then # was Gem::Platform::DARWIN
+      @new_platform = Gem::Platform.new "ppc-darwin"
     else
       @new_platform = Gem::Platform.new platform
     end
@@ -1149,7 +1149,7 @@ class Gem::Specification < Gem::BasicSpecification
     file = file.dup.tap(&Gem::UNTAINT)
     return unless File.file?(file)
 
-    code = Gem.open_file(file, 'r:UTF-8:-', &:read)
+    code = Gem.open_file(file, "r:UTF-8:-", &:read)
 
     code.tap(&Gem::UNTAINT)
 
@@ -1390,7 +1390,7 @@ class Gem::Specification < Gem::BasicSpecification
       @required_rubygems_version,
       @original_platform,
       @dependencies,
-      '', # rubyforge_project
+      "", # rubyforge_project
       @email,
       @authors,
       @description,
@@ -1608,7 +1608,7 @@ class Gem::Specification < Gem::BasicSpecification
     return if default_gem?
     return if File.exist? gem_build_complete_path
     return if !File.writable?(base_dir)
-    return if !File.exist?(File.join(base_dir, 'extensions'))
+    return if !File.exist?(File.join(base_dir, "extensions"))
 
     begin
       # We need to require things in $LOAD_PATH without looking for the
@@ -1616,9 +1616,9 @@ class Gem::Specification < Gem::BasicSpecification
       unresolved_deps = Gem::Specification.unresolved_deps.dup
       Gem::Specification.unresolved_deps.clear
 
-      require_relative 'config_file'
-      require_relative 'ext'
-      require_relative 'user_interaction'
+      require_relative "config_file"
+      require_relative "ext"
+      require_relative "user_interaction"
 
       ui = Gem::SilentUI.new
       Gem::DefaultUserInteraction.use_ui ui do
@@ -1837,7 +1837,7 @@ class Gem::Specification < Gem::BasicSpecification
   #   spec.doc_dir 'ri' # => "/path/to/gem_repo/doc/a-1/ri"
 
   def doc_dir(type = nil)
-    @doc_dir ||= File.join base_dir, 'doc', full_name
+    @doc_dir ||= File.join base_dir, "doc", full_name
 
     if type
       File.join @doc_dir, type
@@ -1849,17 +1849,17 @@ class Gem::Specification < Gem::BasicSpecification
   def encode_with(coder) # :nodoc:
     mark_version
 
-    coder.add 'name', @name
-    coder.add 'version', @version
+    coder.add "name", @name
+    coder.add "version", @version
     platform = case @original_platform
-    when nil, '' then
-      'ruby'
+    when nil, "" then
+      "ruby"
     when String then
       @original_platform
     else
       @original_platform.to_s
     end
-    coder.add 'platform', platform
+    coder.add "platform", platform
 
     attributes = @@attributes.map(&:to_s) - %w[name version platform]
     attributes.each do |name|
@@ -2229,7 +2229,7 @@ class Gem::Specification < Gem::BasicSpecification
   end
 
   def pretty_print(q) # :nodoc:
-    q.group 2, 'Gem::Specification.new do |s|', 'end' do
+    q.group 2, "Gem::Specification.new do |s|", "end" do
       q.breakable
 
       attributes = @@attributes - [:name, :version]
@@ -2324,7 +2324,7 @@ class Gem::Specification < Gem::BasicSpecification
   # Returns the full path to this spec's ri directory.
 
   def ri_dir
-    @ri_dir ||= File.join base_dir, 'ri', full_name
+    @ri_dir ||= File.join base_dir, "ri", full_name
   end
 
   ##
@@ -2334,13 +2334,13 @@ class Gem::Specification < Gem::BasicSpecification
   def ruby_code(obj)
     case obj
     when String             then obj.dump + ".freeze"
-    when Array              then '[' + obj.map {|x| ruby_code x }.join(", ") + ']'
+    when Array              then "[" + obj.map {|x| ruby_code x }.join(", ") + "]"
     when Hash               then
       seg = obj.keys.sort.map {|k| "#{k.to_s.dump} => #{obj[k].to_s.dump}" }
       "{ #{seg.join(', ')} }"
     when Gem::Version       then obj.to_s.dump
-    when DateLike           then obj.strftime('%Y-%m-%d').dump
-    when Time               then obj.strftime('%Y-%m-%d').dump
+    when DateLike           then obj.strftime("%Y-%m-%d").dump
+    when Time               then obj.strftime("%Y-%m-%d").dump
     when Numeric            then obj.inspect
     when true, false, nil   then obj.inspect
     when Gem::Platform      then "Gem::Platform.new(#{obj.to_a.inspect})"
@@ -2562,14 +2562,14 @@ class Gem::Specification < Gem::BasicSpecification
     # back, we have to check again here to make sure that our
     # psych code was properly loaded, and load it if not.
     unless Gem.const_defined?(:NoAliasYAMLTree)
-      require_relative 'psych_tree'
+      require_relative "psych_tree"
     end
 
     builder = Gem::NoAliasYAMLTree.create
     builder << self
     ast = builder.tree
 
-    require 'stringio'
+    require "stringio"
     io = StringIO.new
     io.set_encoding Encoding::UTF_8
 
@@ -2656,7 +2656,7 @@ class Gem::Specification < Gem::BasicSpecification
     # skip to set required_ruby_version when pre-released rubygems.
     # It caused to raise CircularDependencyError
     if @version.prerelease? && (@name.nil? || @name.strip != "rubygems")
-      self.required_rubygems_version = '> 1.3.1'
+      self.required_rubygems_version = "> 1.3.1"
     end
     invalidate_memoized_attributes
 
diff --git a/lib/rubygems/specification_policy.rb b/lib/rubygems/specification_policy.rb
index 8b5d01dda2..332189ae9f 100644
--- a/lib/rubygems/specification_policy.rb
+++ b/lib/rubygems/specification_policy.rb
@@ -1,4 +1,4 @@
-require_relative 'user_interaction'
+require_relative "user_interaction"
 
 class Gem::SpecificationPolicy
   include Gem::UserInteraction
@@ -120,7 +120,7 @@ class Gem::SpecificationPolicy
     metadata = @specification.metadata
 
     unless Hash === metadata
-      error 'metadata must be a hash'
+      error "metadata must be a hash"
     end
 
     metadata.each do |key, value|
@@ -188,7 +188,7 @@ duplicate dependency on #{dep}, (#{prev.requirement}) use:
           prerelease_dep && !@specification.version.prerelease?
 
       open_ended = dep.requirement.requirements.all? do |op, version|
-        not version.prerelease? and (op == '>' or op == '>=')
+        not version.prerelease? and (op == ">" or op == ">=")
       end
 
       if open_ended
@@ -198,12 +198,12 @@ duplicate dependency on #{dep}, (#{prev.requirement}) use:
 
         base = segments.first 2
 
-        recommendation = if (op == '>' || op == '>=') && segments == [0]
+        recommendation = if (op == ">" || op == ">=") && segments == [0]
           "  use a bounded requirement, such as '~> x.y'"
         else
-          bugfix = if op == '>'
+          bugfix = if op == ">"
             ", '> #{dep_version}'"
-          elsif op == '>=' and base != segments
+          elsif op == ">=" and base != segments
             ", '>= #{dep_version}'"
           end
 
@@ -286,7 +286,7 @@ duplicate dependency on #{dep}, (#{prev.requirement}) use:
   def validate_require_paths
     return unless @specification.raw_require_paths.empty?
 
-    error 'specification must have at least one require_path'
+    error "specification must have at least one require_path"
   end
 
   def validate_non_files
@@ -310,7 +310,7 @@ duplicate dependency on #{dep}, (#{prev.requirement}) use:
   def validate_specification_version
     return if @specification.specification_version.is_a?(Integer)
 
-    error 'specification_version must be an Integer (did you mean version?)'
+    error "specification_version must be an Integer (did you mean version?)"
   end
 
   def validate_platform
@@ -380,7 +380,7 @@ http://spdx.org/licenses or '#{Gem::Licenses::NONSTANDARD}' for a nonstandard li
     WARNING
   end
 
-  LAZY = '"FIxxxXME" or "TOxxxDO"'.gsub(/xxx/, '')
+  LAZY = '"FIxxxXME" or "TOxxxDO"'.gsub(/xxx/, "")
   LAZY_PATTERN = /\AFI XME|\ATO DO/x.freeze
   HOMEPAGE_URI_PATTERN = /\A[a-z][a-z\d+.-]*:/i.freeze
 
@@ -405,7 +405,7 @@ http://spdx.org/licenses or '#{Gem::Licenses::NONSTANDARD}' for a nonstandard li
 
     # Make sure a homepage is valid HTTP/HTTPS URI
     if homepage and not homepage.empty?
-      require 'uri'
+      require "uri"
       begin
         homepage_uri = URI.parse(homepage)
         unless [URI::HTTP, URI::HTTPS].member? homepage_uri.class
@@ -445,7 +445,7 @@ http://spdx.org/licenses or '#{Gem::Licenses::NONSTANDARD}' for a nonstandard li
 
   def validate_shebang_line_in(executable)
     executable_path = File.join(@specification.bindir, executable)
-    return if File.read(executable_path, 2) == '#!'
+    return if File.read(executable_path, 2) == "#!"
 
     warning "#{executable_path} is missing #! line"
   end
@@ -457,11 +457,11 @@ http://spdx.org/licenses or '#{Gem::Licenses::NONSTANDARD}' for a nonstandard li
   end
 
   def validate_extensions # :nodoc:
-    require_relative 'ext'
+    require_relative "ext"
     builder = Gem::Ext::Builder.new(@specification)
 
     rake_extension = @specification.extensions.any? {|s| builder.builder_for(s) == Gem::Ext::RakeBuilder }
-    rake_dependency = @specification.dependencies.any? {|d| d.name == 'rake' }
+    rake_dependency = @specification.dependencies.any? {|d| d.name == "rake" }
 
     warning <<-WARNING if rake_extension && !rake_dependency
 You have specified rake based extension, but rake is not added as dependency. It is recommended to add rake as a dependency in gemspec since there's no guarantee rake will be already installed.
diff --git a/lib/rubygems/stub_specification.rb b/lib/rubygems/stub_specification.rb
index b1dd7397ae..33b4f45b0a 100644
--- a/lib/rubygems/stub_specification.rb
+++ b/lib/rubygems/stub_specification.rb
@@ -9,7 +9,7 @@ class Gem::StubSpecification < Gem::BasicSpecification
   PREFIX = "# stub: ".freeze
 
   # :nodoc:
-  OPEN_MODE = 'r:UTF-8:-'.freeze
+  OPEN_MODE = "r:UTF-8:-".freeze
 
   class StubLine # :nodoc: all
     attr_reader :name, :version, :platform, :require_paths, :extensions,
@@ -19,9 +19,9 @@ class Gem::StubSpecification < Gem::BasicSpecification
 
     # These are common require paths.
     REQUIRE_PATHS = { # :nodoc:
-      'lib'  => 'lib'.freeze,
-      'test' => 'test'.freeze,
-      'ext'  => 'ext'.freeze,
+      "lib"  => "lib".freeze,
+      "test" => "test".freeze,
+      "ext"  => "ext".freeze,
     }.freeze
 
     # These are common require path lists.  This hash is used to optimize
@@ -29,7 +29,7 @@ class Gem::StubSpecification < Gem::BasicSpecification
     # in their require paths, so lets take advantage of that by pre-allocating
     # a require path list for that case.
     REQUIRE_PATH_LIST = { # :nodoc:
-      'lib' => ['lib'].freeze,
+      "lib" => ["lib"].freeze,
     }.freeze
 
     def initialize(data, extensions)
diff --git a/lib/rubygems/tsort.rb b/lib/rubygems/tsort.rb
index ebe7c3364b..60ebe22e81 100644
--- a/lib/rubygems/tsort.rb
+++ b/lib/rubygems/tsort.rb
@@ -1,3 +1,3 @@
 # frozen_string_literal: true
 
-require_relative 'tsort/lib/tsort'
+require_relative "tsort/lib/tsort"
diff --git a/lib/rubygems/uninstaller.rb b/lib/rubygems/uninstaller.rb
index a36c5cbe2b..1ae301a44d 100644
--- a/lib/rubygems/uninstaller.rb
+++ b/lib/rubygems/uninstaller.rb
@@ -5,12 +5,12 @@
 # See LICENSE.txt for permissions.
 #++
 
-require 'fileutils'
-require_relative '../rubygems'
-require_relative 'installer_uninstaller_utils'
-require_relative 'dependency_list'
-require_relative 'rdoc'
-require_relative 'user_interaction'
+require "fileutils"
+require_relative "../rubygems"
+require_relative "installer_uninstaller_utils"
+require_relative "dependency_list"
+require_relative "rdoc"
+require_relative "user_interaction"
 
 ##
 # An Uninstaller.
@@ -302,8 +302,8 @@ class Gem::Uninstaller
   # Is +spec+ in +gem_dir+?
 
   def path_ok?(gem_dir, spec)
-    full_path     = File.join gem_dir, 'gems', spec.full_name
-    original_path = File.join gem_dir, 'gems', spec.original_name
+    full_path     = File.join gem_dir, "gems", spec.full_name
+    original_path = File.join gem_dir, "gems", spec.original_name
 
     full_path == spec.full_gem_path || original_path == spec.full_gem_path
   end
@@ -332,10 +332,10 @@ class Gem::Uninstaller
   # Asks if it is OK to remove +spec+.  Returns true if it is OK.
 
   def ask_if_ok(spec) # :nodoc:
-    msg = ['']
-    msg << 'You have requested to uninstall the gem:'
+    msg = [""]
+    msg << "You have requested to uninstall the gem:"
     msg << "\t#{spec.full_name}"
-    msg << ''
+    msg << ""
 
     siblings = Gem::Specification.select do |s|
       s.name == spec.name && s.full_name != spec.full_name
@@ -347,8 +347,8 @@ class Gem::Uninstaller
       end
     end
 
-    msg << 'If you remove this gem, these dependencies will not be met.'
-    msg << 'Continue with Uninstall?'
+    msg << "If you remove this gem, these dependencies will not be met."
+    msg << "Continue with Uninstall?"
     return ask_yes_no(msg.join("\n"), false)
   end
 
@@ -360,7 +360,7 @@ class Gem::Uninstaller
     # of what it did for us to find rather than trying to recreate
     # it again.
     if @format_executable
-      require_relative 'installer'
+      require_relative "installer"
       Gem::Installer.exec_format % File.basename(filename)
     else
       filename
diff --git a/lib/rubygems/uri.rb b/lib/rubygems/uri.rb
index 6acb9041f9..4b5d035aa0 100644
--- a/lib/rubygems/uri.rb
+++ b/lib/rubygems/uri.rb
@@ -66,7 +66,7 @@ class Gem::Uri
   def redact_credentials_from(text)
     return text unless valid_uri? && password? && text.include?(to_s)
 
-    text.sub(password, 'REDACTED')
+    text.sub(password, "REDACTED")
   end
 
   def method_missing(method_name, *args, &blk)
@@ -97,11 +97,11 @@ class Gem::Uri
   end
 
   def with_redacted_user
-    clone.tap {|uri| uri.user = 'REDACTED' }
+    clone.tap {|uri| uri.user = "REDACTED" }
   end
 
   def with_redacted_password
-    clone.tap {|uri| uri.password = 'REDACTED' }
+    clone.tap {|uri| uri.password = "REDACTED" }
   end
 
   def valid_uri?
@@ -113,7 +113,7 @@ class Gem::Uri
   end
 
   def oauth_basic?
-    password == 'x-oauth-basic'
+    password == "x-oauth-basic"
   end
 
   def token?
diff --git a/lib/rubygems/uri_formatter.rb b/lib/rubygems/uri_formatter.rb
index 3bda896875..3f1d02d774 100644
--- a/lib/rubygems/uri_formatter.rb
+++ b/lib/rubygems/uri_formatter.rb
@@ -17,7 +17,7 @@ class Gem::UriFormatter
   # Creates a new URI formatter for +uri+.
 
   def initialize(uri)
-    require 'cgi'
+    require "cgi"
 
     @uri = uri
   end
diff --git a/lib/rubygems/user_interaction.rb b/lib/rubygems/user_interaction.rb
index c726fd21c1..4b0a7c60bb 100644
--- a/lib/rubygems/user_interaction.rb
+++ b/lib/rubygems/user_interaction.rb
@@ -5,8 +5,8 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'deprecate'
-require_relative 'text'
+require_relative "deprecate"
+require_relative "text"
 
 ##
 # Module that defines the default UserInteraction.  Any class including this
@@ -148,7 +148,7 @@ module Gem::UserInteraction
   ##
   # Displays the given +statement+ on the standard output (or equivalent).
 
-  def say(statement = '')
+  def say(statement = "")
     ui.say statement
   end
 
@@ -259,11 +259,11 @@ class Gem::StreamUI
 
     default_answer = case default
     when nil
-      'yn'
+      "yn"
     when true
-      'Yn'
+      "Yn"
     else
-      'yN'
+      "yN"
     end
 
     result = nil
@@ -312,7 +312,7 @@ class Gem::StreamUI
   def require_io_console
     @require_io_console ||= begin
       begin
-        require 'io/console'
+        require "io/console"
       rescue LoadError
       end
       true
@@ -472,7 +472,7 @@ class Gem::StreamUI
     # and the +terminal_message+ when it is complete.
 
     def initialize(out_stream, size, initial_message,
-                   terminal_message = 'complete')
+                   terminal_message = "complete")
       @out = out_stream
       @total = size
       @count = 0
diff --git a/lib/rubygems/util.rb b/lib/rubygems/util.rb
index 9fd78ab2bc..356c46a5a1 100644
--- a/lib/rubygems/util.rb
+++ b/lib/rubygems/util.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative 'deprecate'
+require_relative "deprecate"
 
 ##
 # This module contains various utility methods as module methods.
@@ -10,9 +10,9 @@ module Gem::Util
   # Zlib::GzipReader wrapper that unzips +data+.
 
   def self.gunzip(data)
-    require 'zlib'
-    require 'stringio'
-    data = StringIO.new(data, 'r')
+    require "zlib"
+    require "stringio"
+    data = StringIO.new(data, "r")
 
     gzip_reader = begin
                     Zlib::GzipReader.new(data)
@@ -29,9 +29,9 @@ module Gem::Util
   # Zlib::GzipWriter wrapper that zips +data+.
 
   def self.gzip(data)
-    require 'zlib'
-    require 'stringio'
-    zipped = StringIO.new(String.new, 'w')
+    require "zlib"
+    require "stringio"
+    zipped = StringIO.new(String.new, "w")
     zipped.set_encoding Encoding::BINARY
 
     Zlib::GzipWriter.wrap zipped do |io|
@@ -45,7 +45,7 @@ module Gem::Util
   # A Zlib::Inflate#inflate wrapper
 
   def self.inflate(data)
-    require 'zlib'
+    require "zlib"
     Zlib::Inflate.inflate data
   end
 
@@ -86,7 +86,7 @@ module Gem::Util
     loop do
       Dir.chdir here, &block rescue Errno::EACCES
 
-      new_here = File.expand_path('..', here)
+      new_here = File.expand_path("..", here)
       return if new_here == here # toplevel
       here = new_here
     end
@@ -109,7 +109,7 @@ module Gem::Util
   # comes with a leading slash.
 
   def self.correct_for_windows_path(path)
-    if path[0].chr == '/' && path[1].chr =~ /[a-z]/i && path[2].chr == ':'
+    if path[0].chr == "/" && path[1].chr =~ /[a-z]/i && path[2].chr == ":"
       path[1..-1]
     else
       path
diff --git a/lib/rubygems/util/licenses.rb b/lib/rubygems/util/licenses.rb
index 3f4178c6e0..96f47781c0 100644
--- a/lib/rubygems/util/licenses.rb
+++ b/lib/rubygems/util/licenses.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
-require_relative '../text'
+require_relative "../text"
 
 class Gem::Licenses
   extend Gem::Text
 
-  NONSTANDARD = 'Nonstandard'.freeze
-  LICENSE_REF = 'LicenseRef-.+'.freeze
+  NONSTANDARD = "Nonstandard".freeze
+  LICENSE_REF = "LicenseRef-.+".freeze
 
   # Software Package Data Exchange (SPDX) standard open-source software
   # license identifiers
diff --git a/lib/rubygems/validator.rb b/lib/rubygems/validator.rb
index 728595e778..60104a34d5 100644
--- a/lib/rubygems/validator.rb
+++ b/lib/rubygems/validator.rb
@@ -5,8 +5,8 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative 'package'
-require_relative 'installer'
+require_relative "package"
+require_relative "installer"
 
 ##
 # Validator performs various gem file and gem database validation
@@ -15,7 +15,7 @@ class Gem::Validator
   include Gem::UserInteraction
 
   def initialize # :nodoc:
-    require 'find'
+    require "find"
   end
 
   private
@@ -110,11 +110,11 @@ class Gem::Validator
             begin
               next unless data # HACK `gem check -a mkrf`
 
-              source = File.join gem_directory, entry['path']
+              source = File.join gem_directory, entry["path"]
 
               File.open source, Gem.binary_mode do |f|
                 unless f.read == data
-                  errors[gem_name][entry['path']] = "Modified from original"
+                  errors[gem_name][entry["path"]] = "Modified from original"
                 end
               end
             end
diff --git a/lib/rubygems/version.rb b/lib/rubygems/version.rb
index c57bf7d6d5..03ae5ca17e 100644
--- a/lib/rubygems/version.rb
+++ b/lib/rubygems/version.rb
@@ -276,7 +276,7 @@ class Gem::Version
   end
 
   def yaml_initialize(tag, map) # :nodoc:
-    @version = map['version']
+    @version = map["version"]
     @segments = nil
     @hash = nil
   end
@@ -286,7 +286,7 @@ class Gem::Version
   end
 
   def encode_with(coder) # :nodoc:
-    coder.add 'version', @version
+    coder.add "version", @version
   end
 
   ##
@@ -311,7 +311,7 @@ class Gem::Version
     @@release[self] ||= if prerelease?
       segments = self.segments
       segments.pop while segments.any? {|s| String === s }
-      self.class.new segments.join('.')
+      self.class.new segments.join(".")
     else
       self
     end
diff --git a/lib/rubygems/version_option.rb b/lib/rubygems/version_option.rb
index 1db382fa7f..a487a0bc24 100644
--- a/lib/rubygems/version_option.rb
+++ b/lib/rubygems/version_option.rb
@@ -5,7 +5,7 @@
 # See LICENSE.txt for permissions.
 #++
 
-require_relative '../rubygems'
+require_relative "../rubygems"
 
 ##
 # Mixin methods for --version and --platform Gem::Command options.
@@ -24,7 +24,7 @@ module Gem::VersionOption
       end
     end
 
-    add_option('--platform PLATFORM', Gem::Platform,
+    add_option("--platform PLATFORM", Gem::Platform,
                "Specify the platform of gem to #{task}", *wrap) do
                  |value, options|
       unless options[:added_platform]
@@ -55,7 +55,7 @@ module Gem::VersionOption
       Gem::Requirement.new(*value.split(/\s*,\s*/))
     end
 
-    add_option('-v', '--version VERSION', Gem::Requirement,
+    add_option("-v", "--version VERSION", Gem::Requirement,
                "Specify version of gem to #{task}", *wrap) do
                  |value, options|
       # Allow handling for multiple --version operators