Merge bundler to standard libraries.

  rubygems 2.7.x depends bundler-1.15.x. This is preparation for
  rubygems and bundler migration.

  * lib/bundler.rb, lib/bundler/*: files of bundler-1.15.4
  * spec/bundler/*: rspec examples of bundler-1.15.4. I applied patches.
    * https://github.com/bundler/bundler/pull/6007
    * Exclude not working examples on ruby repository.
    * Fake ruby interpriter instead of installed ruby.
  * Makefile.in: Added test task named `test-bundler`. This task is only
    working macOS/linux yet. I'm going to support Windows environment later.
  * tool/sync_default_gems.rb: Added sync task for bundler.

  [Feature #12733][ruby-core:77172]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59779 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

7 files changed, 1439 insertions, 0 deletions

diff --git a/lib/bundler/source/gemspec.rb b/lib/bundler/source/gemspec.rb
new file mode 100644
index 0000000000..05e613277f
--- /dev/null
+++ b/lib/bundler/source/gemspec.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+module Bundler
+  class Source
+    class Gemspec < Path
+      attr_reader :gemspec
+
+      def initialize(options)
+        super
+        @gemspec = options["gemspec"]
+      end
+
+      def as_path_source
+        Path.new(options)
+      end
+    end
+  end
+end
diff --git a/lib/bundler/source/git.rb b/lib/bundler/source/git.rb
new file mode 100644
index 0000000000..b3e218e390
--- /dev/null
+++ b/lib/bundler/source/git.rb
@@ -0,0 +1,324 @@
+# frozen_string_literal: true
+require "fileutils"
+require "uri"
+require "digest/sha1"
+
+module Bundler
+  class Source
+    class Git < Path
+      autoload :GitProxy, "bundler/source/git/git_proxy"
+
+      attr_reader :uri, :ref, :branch, :options, :submodules
+
+      def initialize(options)
+        @options = options
+        @glob = options["glob"] || DEFAULT_GLOB
+
+        @allow_cached = false
+        @allow_remote = false
+
+        # Stringify options that could be set as symbols
+        %w(ref branch tag revision).each {|k| options[k] = options[k].to_s if options[k] }
+
+        @uri        = options["uri"] || ""
+        @branch     = options["branch"]
+        @ref        = options["ref"] || options["branch"] || options["tag"] || "master"
+        @submodules = options["submodules"]
+        @name       = options["name"]
+        @version    = options["version"].to_s.strip.gsub("-", ".pre.")
+
+        @copied     = false
+        @local      = false
+      end
+
+      def self.from_lock(options)
+        new(options.merge("uri" => options.delete("remote")))
+      end
+
+      def to_lock
+        out = String.new("GIT\n")
+        out << "  remote: #{@uri}\n"
+        out << "  revision: #{revision}\n"
+        %w(ref branch tag submodules).each do |opt|
+          out << "  #{opt}: #{options[opt]}\n" if options[opt]
+        end
+        out << "  glob: #{@glob}\n" unless @glob == DEFAULT_GLOB
+        out << "  specs:\n"
+      end
+
+      def hash
+        [self.class, uri, ref, branch, name, version, submodules].hash
+      end
+
+      def eql?(other)
+        other.is_a?(Git) && uri == other.uri && ref == other.ref &&
+          branch == other.branch && name == other.name &&
+          version == other.version && submodules == other.submodules
+      end
+
+      alias_method :==, :eql?
+
+      def to_s
+        at = if local?
+          path
+        elsif user_ref = options["ref"]
+          if ref =~ /\A[a-z0-9]{4,}\z/i
+            shortref_for_display(user_ref)
+          else
+            user_ref
+          end
+        else
+          ref
+        end
+
+        rev = begin
+                "@#{shortref_for_display(revision)}"
+              rescue GitError
+                nil
+              end
+
+        "#{uri} (at #{at}#{rev})"
+      end
+
+      def name
+        File.basename(@uri, ".git")
+      end
+
+      # This is the path which is going to contain a specific
+      # checkout of the git repository. When using local git
+      # repos, this is set to the local repo.
+      def install_path
+        @install_path ||= begin
+          git_scope = "#{base_name}-#{shortref_for_path(revision)}"
+
+          path = Bundler.install_path.join(git_scope)
+
+          if !path.exist? && Bundler.requires_sudo?
+            Bundler.user_bundle_path.join(Bundler.ruby_scope).join(git_scope)
+          else
+            path
+          end
+        end
+      end
+
+      alias_method :path, :install_path
+
+      def extension_dir_name
+        "#{base_name}-#{shortref_for_path(revision)}"
+      end
+
+      def unlock!
+        git_proxy.revision = nil
+        options["revision"] = nil
+
+        @unlocked = true
+      end
+
+      def local_override!(path)
+        return false if local?
+
+        path = Pathname.new(path)
+        path = path.expand_path(Bundler.root) unless path.relative?
+
+        unless options["branch"] || Bundler.settings[:disable_local_branch_check]
+          raise GitError, "Cannot use local override for #{name} at #{path} because " \
+            ":branch is not specified in Gemfile. Specify a branch or use " \
+            "`bundle config --delete` to remove the local override"
+        end
+
+        unless path.exist?
+          raise GitError, "Cannot use local override for #{name} because #{path} " \
+            "does not exist. Check `bundle config --delete` to remove the local override"
+        end
+
+        set_local!(path)
+
+        # Create a new git proxy without the cached revision
+        # so the Gemfile.lock always picks up the new revision.
+        @git_proxy = GitProxy.new(path, uri, ref)
+
+        if git_proxy.branch != options["branch"] && !Bundler.settings[:disable_local_branch_check]
+          raise GitError, "Local override for #{name} at #{path} is using branch " \
+            "#{git_proxy.branch} but Gemfile specifies #{options["branch"]}"
+        end
+
+        changed = cached_revision && cached_revision != git_proxy.revision
+
+        if changed && !@unlocked && !git_proxy.contains?(cached_revision)
+          raise GitError, "The Gemfile lock is pointing to revision #{shortref_for_display(cached_revision)} " \
+            "but the current branch in your local override for #{name} does not contain such commit. " \
+            "Please make sure your branch is up to date."
+        end
+
+        changed
+      end
+
+      def specs(*)
+        set_local!(app_cache_path) if has_app_cache? && !local?
+
+        if requires_checkout? && !@copied
+          fetch
+          git_proxy.copy_to(install_path, submodules)
+          serialize_gemspecs_in(install_path)
+          @copied = true
+        end
+
+        local_specs
+      end
+
+      def install(spec, options = {})
+        force = options[:force]
+
+        Bundler.ui.info "Using #{version_message(spec)} from #{self}"
+
+        if requires_checkout? && !@copied && !force
+          Bundler.ui.debug "  * Checking out revision: #{ref}"
+          git_proxy.copy_to(install_path, submodules)
+          serialize_gemspecs_in(install_path)
+          @copied = true
+        elsif force
+          git_proxy.copy_to(install_path, submodules)
+        end
+
+        generate_bin_options = { :disable_extensions => !Bundler.rubygems.spec_missing_extensions?(spec), :build_args => options[:build_args] }
+        generate_bin(spec, generate_bin_options)
+
+        requires_checkout? ? spec.post_install_message : nil
+      end
+
+      def cache(spec, custom_path = nil)
+        app_cache_path = app_cache_path(custom_path)
+        return unless Bundler.settings[:cache_all]
+        return if path == app_cache_path
+        cached!
+        FileUtils.rm_rf(app_cache_path)
+        git_proxy.checkout if requires_checkout?
+        git_proxy.copy_to(app_cache_path, @submodules)
+        serialize_gemspecs_in(app_cache_path)
+      end
+
+      def load_spec_files
+        super
+      rescue PathError => e
+        Bundler.ui.trace e
+        raise GitError, "#{self} is not yet checked out. Run `bundle install` first."
+      end
+
+      # This is the path which is going to contain a cache
+      # of the git repository. When using the same git repository
+      # across different projects, this cache will be shared.
+      # When using local git repos, this is set to the local repo.
+      def cache_path
+        @cache_path ||= begin
+          git_scope = "#{base_name}-#{uri_hash}"
+
+          if Bundler.requires_sudo?
+            Bundler.user_bundle_path.join("cache/git", git_scope)
+          else
+            Bundler.cache.join("git", git_scope)
+          end
+        end
+      end
+
+      def app_cache_dirname
+        "#{base_name}-#{shortref_for_path(cached_revision || revision)}"
+      end
+
+      def revision
+        git_proxy.revision
+      end
+
+      def allow_git_ops?
+        @allow_remote || @allow_cached
+      end
+
+    private
+
+      def serialize_gemspecs_in(destination)
+        destination = destination.expand_path(Bundler.root) if destination.relative?
+        Dir["#{destination}/#{@glob}"].each do |spec_path|
+          # Evaluate gemspecs and cache the result. Gemspecs
+          # in git might require git or other dependencies.
+          # The gemspecs we cache should already be evaluated.
+          spec = Bundler.load_gemspec(spec_path)
+          next unless spec
+          Bundler.rubygems.set_installed_by_version(spec)
+          Bundler.rubygems.validate(spec)
+          File.open(spec_path, "wb") {|file| file.write(spec.to_ruby) }
+        end
+      end
+
+      def set_local!(path)
+        @local       = true
+        @local_specs = @git_proxy = nil
+        @cache_path  = @install_path = path
+      end
+
+      def has_app_cache?
+        cached_revision && super
+      end
+
+      def local?
+        @local
+      end
+
+      def requires_checkout?
+        allow_git_ops? && !local?
+      end
+
+      def base_name
+        File.basename(uri.sub(%r{^(\w+://)?([^/:]+:)?(//\w*/)?(\w*/)*}, ""), ".git")
+      end
+
+      def shortref_for_display(ref)
+        ref[0..6]
+      end
+
+      def shortref_for_path(ref)
+        ref[0..11]
+      end
+
+      def uri_hash
+        if uri =~ %r{^\w+://(\w+@)?}
+          # Downcase the domain component of the URI
+          # and strip off a trailing slash, if one is present
+          input = URI.parse(uri).normalize.to_s.sub(%r{/$}, "")
+        else
+          # If there is no URI scheme, assume it is an ssh/git URI
+          input = uri
+        end
+        Digest::SHA1.hexdigest(input)
+      end
+
+      def cached_revision
+        options["revision"]
+      end
+
+      def cached?
+        cache_path.exist?
+      end
+
+      def git_proxy
+        @git_proxy ||= GitProxy.new(cache_path, uri, ref, cached_revision, self)
+      end
+
+      def fetch
+        git_proxy.checkout
+      rescue GitError
+        raise unless Bundler.feature_flag.allow_offline_install?
+        Bundler.ui.warn "Using cached git data because of network errors"
+      end
+
+      # no-op, since we validate when re-serializing the gemspec
+      def validate_spec(_spec); end
+
+      if Bundler.rubygems.stubs_provide_full_functionality?
+        def load_gemspec(file)
+          stub = Gem::StubSpecification.gemspec_stub(file, install_path.parent, install_path.parent)
+          stub.full_gem_path = Pathname.new(file).dirname.expand_path(root).to_s.untaint
+          StubSpecification.from_stub(stub)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/bundler/source/git/git_proxy.rb b/lib/bundler/source/git/git_proxy.rb
new file mode 100644
index 0000000000..c05d7a5afa
--- /dev/null
+++ b/lib/bundler/source/git/git_proxy.rb
@@ -0,0 +1,252 @@
+# frozen_string_literal: true
+require "shellwords"
+require "tempfile"
+module Bundler
+  class Source
+    class Git
+      class GitNotInstalledError < GitError
+        def initialize
+          msg = String.new
+          msg << "You need to install git to be able to use gems from git repositories. "
+          msg << "For help installing git, please refer to GitHub's tutorial at https://help.github.com/articles/set-up-git"
+          super msg
+        end
+      end
+
+      class GitNotAllowedError < GitError
+        def initialize(command)
+          msg = String.new
+          msg << "Bundler is trying to run a `git #{command}` at runtime. You probably need to run `bundle install`. However, "
+          msg << "this error message could probably be more useful. Please submit a ticket at http://github.com/bundler/bundler/issues "
+          msg << "with steps to reproduce as well as the following\n\nCALLER: #{caller.join("\n")}"
+          super msg
+        end
+      end
+
+      class GitCommandError < GitError
+        def initialize(command, path = nil, extra_info = nil)
+          msg = String.new
+          msg << "Git error: command `git #{command}` in directory #{SharedHelpers.pwd} has failed."
+          msg << "\n#{extra_info}" if extra_info
+          msg << "\nIf this error persists you could try removing the cache directory '#{path}'" if path && path.exist?
+          super msg
+        end
+      end
+
+      class MissingGitRevisionError < GitError
+        def initialize(ref, repo)
+          msg = "Revision #{ref} does not exist in the repository #{repo}. Maybe you misspelled it?"
+          super msg
+        end
+      end
+
+      # The GitProxy is responsible to interact with git repositories.
+      # All actions required by the Git source is encapsulated in this
+      # object.
+      class GitProxy
+        attr_accessor :path, :uri, :ref
+        attr_writer :revision
+
+        def initialize(path, uri, ref, revision = nil, git = nil)
+          @path     = path
+          @uri      = uri
+          @ref      = ref
+          @revision = revision
+          @git      = git
+          raise GitNotInstalledError.new if allow? && !Bundler.git_present?
+        end
+
+        def revision
+          return @revision if @revision
+
+          begin
+            @revision ||= find_local_revision
+          rescue GitCommandError
+            raise MissingGitRevisionError.new(ref, uri)
+          end
+
+          @revision
+        end
+
+        def branch
+          @branch ||= allowed_in_path do
+            git("rev-parse --abbrev-ref HEAD").strip
+          end
+        end
+
+        def contains?(commit)
+          allowed_in_path do
+            result = git_null("branch --contains #{commit}")
+            $? == 0 && result =~ /^\* (.*)$/
+          end
+        end
+
+        def version
+          git("--version").match(/(git version\s*)?((\.?\d+)+).*/)[2]
+        end
+
+        def full_version
+          git("--version").sub("git version", "").strip
+        end
+
+        def checkout
+          if path.exist?
+            return if has_revision_cached?
+            Bundler.ui.info "Fetching #{URICredentialsFilter.credential_filtered_uri(uri)}"
+            in_path do
+              git_retry %(fetch --force --quiet --tags #{uri_escaped_with_configured_credentials} "refs/heads/*:refs/heads/*")
+            end
+          else
+            Bundler.ui.info "Fetching #{URICredentialsFilter.credential_filtered_uri(uri)}"
+            SharedHelpers.filesystem_access(path.dirname) do |p|
+              FileUtils.mkdir_p(p)
+            end
+            git_retry %(clone #{uri_escaped_with_configured_credentials} "#{path}" --bare --no-hardlinks --quiet)
+          end
+        end
+
+        def copy_to(destination, submodules = false)
+          # method 1
+          unless File.exist?(destination.join(".git"))
+            begin
+              SharedHelpers.filesystem_access(destination.dirname) do |p|
+                FileUtils.mkdir_p(p)
+              end
+              SharedHelpers.filesystem_access(destination) do |p|
+                FileUtils.rm_rf(p)
+              end
+              git_retry %(clone --no-checkout --quiet "#{path}" "#{destination}")
+              File.chmod(((File.stat(destination).mode | 0o777) & ~File.umask), destination)
+            rescue Errno::EEXIST => e
+              file_path = e.message[%r{.*?(/.*)}, 1]
+              raise GitError, "Bundler could not install a gem because it needs to " \
+                "create a directory, but a file exists - #{file_path}. Please delete " \
+                "this file and try again."
+            end
+          end
+          # method 2
+          SharedHelpers.chdir(destination) do
+            git_retry %(fetch --force --quiet --tags "#{path}")
+            git "reset --hard #{@revision}"
+
+            if submodules
+              git_retry "submodule update --init --recursive"
+            elsif Gem::Version.create(version) >= Gem::Version.create("2.9.0")
+              git_retry "submodule deinit --all --force"
+            end
+          end
+        end
+
+      private
+
+        # TODO: Do not rely on /dev/null.
+        # Given that open3 is not cross platform until Ruby 1.9.3,
+        # the best solution is to pipe to /dev/null if it exists.
+        # If it doesn't, everything will work fine, but the user
+        # will get the $stderr messages as well.
+        def git_null(command)
+          git("#{command} 2>#{Bundler::NULL}", false)
+        end
+
+        def git_retry(command)
+          Bundler::Retry.new("`git #{command}`", GitNotAllowedError).attempts do
+            git(command)
+          end
+        end
+
+        def git(command, check_errors = true, error_msg = nil)
+          command_with_no_credentials = URICredentialsFilter.credential_filtered_string(command, uri)
+          raise GitNotAllowedError.new(command_with_no_credentials) unless allow?
+
+          out = SharedHelpers.with_clean_git_env do
+            capture_and_filter_stderr(uri) { `git #{command}` }
+          end
+
+          stdout_with_no_credentials = URICredentialsFilter.credential_filtered_string(out, uri)
+          raise GitCommandError.new(command_with_no_credentials, path, error_msg) if check_errors && !$?.success?
+          stdout_with_no_credentials
+        end
+
+        def has_revision_cached?
+          return unless @revision
+          in_path { git("cat-file -e #{@revision}") }
+          true
+        rescue GitError
+          false
+        end
+
+        def remove_cache
+          FileUtils.rm_rf(path)
+        end
+
+        def find_local_revision
+          allowed_in_path do
+            git("rev-parse --verify #{Shellwords.shellescape(ref)}", true).strip
+          end
+        end
+
+        # Escape the URI for git commands
+        def uri_escaped_with_configured_credentials
+          remote = configured_uri_for(uri)
+          if Bundler::WINDOWS
+            # Windows quoting requires double quotes only, with double quotes
+            # inside the string escaped by being doubled.
+            '"' + remote.gsub('"') { '""' } + '"'
+          else
+            # Bash requires single quoted strings, with the single quotes escaped
+            # by ending the string, escaping the quote, and restarting the string.
+            "'" + remote.gsub("'") { "'\\''" } + "'"
+          end
+        end
+
+        # Adds credentials to the URI as Fetcher#configured_uri_for does
+        def configured_uri_for(uri)
+          if /https?:/ =~ uri
+            remote = URI(uri)
+            config_auth = Bundler.settings[remote.to_s] || Bundler.settings[remote.host]
+            remote.userinfo ||= config_auth
+            remote.to_s
+          else
+            uri
+          end
+        end
+
+        def allow?
+          @git ? @git.allow_git_ops? : true
+        end
+
+        def in_path(&blk)
+          checkout unless path.exist?
+          SharedHelpers.chdir(path, &blk)
+        end
+
+        def allowed_in_path
+          return in_path { yield } if allow?
+          raise GitError, "The git source #{uri} is not yet checked out. Please run `bundle install` before trying to start your application"
+        end
+
+        # TODO: Replace this with Open3 when upgrading to bundler 2
+        # Similar to #git_null, as Open3 is not cross-platform,
+        # a temporary way is to use Tempfile to capture the stderr.
+        # When replacing this using Open3, make sure git_null is
+        # also replaced by Open3, so stdout and stderr all got handled properly.
+        def capture_and_filter_stderr(uri)
+          return_value, captured_err = ""
+          backup_stderr = STDERR.dup
+          begin
+            Tempfile.open("captured_stderr") do |f|
+              STDERR.reopen(f)
+              return_value = yield
+              f.rewind
+              captured_err = f.read
+            end
+          ensure
+            STDERR.reopen backup_stderr
+          end
+          $stderr.puts URICredentialsFilter.credential_filtered_string(captured_err, uri) if uri && !captured_err.empty?
+          return_value
+        end
+      end
+    end
+  end
+end
diff --git a/lib/bundler/source/path.rb b/lib/bundler/source/path.rb
new file mode 100644
index 0000000000..8dd0763cc1
--- /dev/null
+++ b/lib/bundler/source/path.rb
@@ -0,0 +1,249 @@
+# frozen_string_literal: true
+module Bundler
+  class Source
+    class Path < Source
+      autoload :Installer, "bundler/source/path/installer"
+
+      attr_reader :path, :options, :root_path, :original_path
+      attr_writer :name
+      attr_accessor :version
+
+      protected :original_path
+
+      DEFAULT_GLOB = "{,*,*/*}.gemspec".freeze
+
+      def initialize(options)
+        @options = options.dup
+        @glob = options["glob"] || DEFAULT_GLOB
+
+        @allow_cached = false
+        @allow_remote = false
+
+        @root_path = options["root_path"] || Bundler.root
+
+        if options["path"]
+          @path = Pathname.new(options["path"])
+          @path = expand(@path) unless @path.relative?
+        end
+
+        @name    = options["name"]
+        @version = options["version"]
+
+        # Stores the original path. If at any point we move to the
+        # cached directory, we still have the original path to copy from.
+        @original_path = @path
+      end
+
+      def remote!
+        @allow_remote = true
+      end
+
+      def cached!
+        @allow_cached = true
+      end
+
+      def self.from_lock(options)
+        new(options.merge("path" => options.delete("remote")))
+      end
+
+      def to_lock
+        out = String.new("PATH\n")
+        out << "  remote: #{lockfile_path}\n"
+        out << "  glob: #{@glob}\n" unless @glob == DEFAULT_GLOB
+        out << "  specs:\n"
+      end
+
+      def to_s
+        "source at `#{@path}`"
+      end
+
+      def hash
+        [self.class, expanded_path, version].hash
+      end
+
+      def eql?(other)
+        return unless other.class == self.class
+        expanded_original_path == other.expanded_original_path &&
+          version == other.version
+      end
+
+      alias_method :==, :eql?
+
+      def name
+        File.basename(expanded_path.to_s)
+      end
+
+      def install(spec, options = {})
+        Bundler.ui.info "Using #{version_message(spec)} from #{self}"
+        generate_bin(spec, :disable_extensions => true)
+        nil # no post-install message
+      end
+
+      def cache(spec, custom_path = nil)
+        app_cache_path = app_cache_path(custom_path)
+        return unless Bundler.settings[:cache_all]
+        return if expand(@original_path).to_s.index(root_path.to_s + "/") == 0
+
+        unless @original_path.exist?
+          raise GemNotFound, "Can't cache gem #{version_message(spec)} because #{self} is missing!"
+        end
+
+        FileUtils.rm_rf(app_cache_path)
+        FileUtils.cp_r("#{@original_path}/.", app_cache_path)
+        FileUtils.touch(app_cache_path.join(".bundlecache"))
+      end
+
+      def local_specs(*)
+        @local_specs ||= load_spec_files
+      end
+
+      def specs
+        if has_app_cache?
+          @path = app_cache_path
+          @expanded_path = nil # Invalidate
+        end
+        local_specs
+      end
+
+      def app_cache_dirname
+        name
+      end
+
+      def root
+        Bundler.root
+      end
+
+      def is_a_path?
+        instance_of?(Path)
+      end
+
+      def expanded_original_path
+        @expanded_original_path ||= expand(original_path)
+      end
+
+    private
+
+      def expanded_path
+        @expanded_path ||= expand(path)
+      end
+
+      def expand(somepath)
+        somepath.expand_path(root_path)
+      rescue ArgumentError => e
+        Bundler.ui.debug(e)
+        raise PathError, "There was an error while trying to use the path " \
+          "`#{somepath}`.\nThe error message was: #{e.message}."
+      end
+
+      def lockfile_path
+        return relative_path(original_path) if original_path.absolute?
+        expand(original_path).relative_path_from(Bundler.root)
+      end
+
+      def app_cache_path(custom_path = nil)
+        @app_cache_path ||= Bundler.app_cache(custom_path).join(app_cache_dirname)
+      end
+
+      def has_app_cache?
+        SharedHelpers.in_bundle? && app_cache_path.exist?
+      end
+
+      def load_gemspec(file)
+        return unless spec = Bundler.load_gemspec(file)
+        Bundler.rubygems.set_installed_by_version(spec)
+        spec
+      end
+
+      def validate_spec(spec)
+        Bundler.rubygems.validate(spec)
+      end
+
+      def load_spec_files
+        index = Index.new
+
+        if File.directory?(expanded_path)
+          # We sort depth-first since `<<` will override the earlier-found specs
+          Dir["#{expanded_path}/#{@glob}"].sort_by {|p| -p.split(File::SEPARATOR).size }.each do |file|
+            next unless spec = load_gemspec(file)
+            spec.source = self
+
+            # Validation causes extension_dir to be calculated, which depends
+            # on #source, so we validate here instead of load_gemspec
+            validate_spec(spec)
+            index << spec
+          end
+
+          if index.empty? && @name && @version
+            index << Gem::Specification.new do |s|
+              s.name     = @name
+              s.source   = self
+              s.version  = Gem::Version.new(@version)
+              s.platform = Gem::Platform::RUBY
+              s.summary  = "Fake gemspec for #{@name}"
+              s.relative_loaded_from = "#{@name}.gemspec"
+              s.authors = ["no one"]
+              if expanded_path.join("bin").exist?
+                executables = expanded_path.join("bin").children
+                executables.reject! {|p| File.directory?(p) }
+                s.executables = executables.map {|c| c.basename.to_s }
+              end
+            end
+          end
+        else
+          message = String.new("The path `#{expanded_path}` ")
+          message << if File.exist?(expanded_path)
+                       "is not a directory."
+                     else
+                       "does not exist."
+                     end
+          raise PathError, message
+        end
+
+        index
+      end
+
+      def relative_path(path = self.path)
+        if path.to_s.start_with?(root_path.to_s)
+          return path.relative_path_from(root_path)
+        end
+        path
+      end
+
+      def generate_bin(spec, options = {})
+        gem_dir = Pathname.new(spec.full_gem_path)
+
+        # Some gem authors put absolute paths in their gemspec
+        # and we have to save them from themselves
+        spec.files = spec.files.map do |p|
+          next p unless p =~ /\A#{Pathname::SEPARATOR_PAT}/
+          next if File.directory?(p)
+          begin
+            Pathname.new(p).relative_path_from(gem_dir).to_s
+          rescue ArgumentError
+            p
+          end
+        end.compact
+
+        installer = Path::Installer.new(
+          spec,
+          :env_shebang => false,
+          :disable_extensions => options[:disable_extensions],
+          :build_args => options[:build_args]
+        )
+        installer.post_install
+      rescue Gem::InvalidSpecificationException => e
+        Bundler.ui.warn "\n#{spec.name} at #{spec.full_gem_path} did not have a valid gemspec.\n" \
+                        "This prevents bundler from installing bins or native extensions, but " \
+                        "that may not affect its functionality."
+
+        if !spec.extensions.empty? && !spec.email.empty?
+          Bundler.ui.warn "If you need to use this package without installing it from a gem " \
+                          "repository, please contact #{spec.email} and ask them " \
+                          "to modify their .gemspec so it can work with `gem build`."
+        end
+
+        Bundler.ui.warn "The validation message from Rubygems was:\n  #{e.message}"
+      end
+    end
+  end
+end
diff --git a/lib/bundler/source/path/installer.rb b/lib/bundler/source/path/installer.rb
new file mode 100644
index 0000000000..9c2f74a31b
--- /dev/null
+++ b/lib/bundler/source/path/installer.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+module Bundler
+  class Source
+    class Path
+      class Installer < Bundler::RubyGemsGemInstaller
+        attr_reader :spec
+
+        def initialize(spec, options = {})
+          @spec               = spec
+          @gem_dir            = Bundler.rubygems.path(spec.full_gem_path)
+          @wrappers           = true
+          @env_shebang        = true
+          @format_executable  = options[:format_executable] || false
+          @build_args         = options[:build_args] || Bundler.rubygems.build_args
+          @gem_bin_dir        = "#{Bundler.rubygems.gem_dir}/bin"
+          @disable_extensions = options[:disable_extensions]
+
+          if Bundler.requires_sudo?
+            @tmp_dir = Bundler.tmp(spec.full_name).to_s
+            @bin_dir = "#{@tmp_dir}/bin"
+          else
+            @bin_dir = @gem_bin_dir
+          end
+        end
+
+        def post_install
+          SharedHelpers.chdir(@gem_dir) do
+            run_hooks(:pre_install)
+
+            unless @disable_extensions
+              build_extensions
+              run_hooks(:post_build)
+            end
+
+            generate_bin unless spec.executables.nil? || spec.executables.empty?
+
+            run_hooks(:post_install)
+          end
+        ensure
+          Bundler.rm_rf(@tmp_dir) if Bundler.requires_sudo?
+        end
+
+      private
+
+        def generate_bin
+          super
+
+          if Bundler.requires_sudo?
+            SharedHelpers.filesystem_access(@gem_bin_dir) do |p|
+              Bundler.mkdir_p(p)
+            end
+            spec.executables.each do |exe|
+              Bundler.sudo "cp -R #{@bin_dir}/#{exe} #{@gem_bin_dir}"
+            end
+          end
+        end
+
+        def run_hooks(type)
+          hooks_meth = "#{type}_hooks"
+          return unless Gem.respond_to?(hooks_meth)
+          Gem.send(hooks_meth).each do |hook|
+            result = hook.call(self)
+            next unless result == false
+            location = " at #{$1}" if hook.inspect =~ /@(.*:\d+)/
+            message = "#{type} hook#{location} failed for #{spec.full_name}"
+            raise InstallHookError, message
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/bundler/source/rubygems.rb b/lib/bundler/source/rubygems.rb
new file mode 100644
index 0000000000..353194f53f
--- /dev/null
+++ b/lib/bundler/source/rubygems.rb
@@ -0,0 +1,462 @@
+# frozen_string_literal: true
+require "uri"
+require "rubygems/user_interaction"
+
+module Bundler
+  class Source
+    class Rubygems < Source
+      autoload :Remote, "bundler/source/rubygems/remote"
+
+      # Use the API when installing less than X gems
+      API_REQUEST_LIMIT = 500
+      # Ask for X gems per API request
+      API_REQUEST_SIZE = 50
+
+      attr_reader :remotes, :caches
+
+      def initialize(options = {})
+        @options = options
+        @remotes = []
+        @dependency_names = []
+        @allow_remote = false
+        @allow_cached = false
+        @caches = [cache_path, *Bundler.rubygems.gem_cache]
+
+        Array(options["remotes"] || []).reverse_each {|r| add_remote(r) }
+      end
+
+      def remote!
+        @specs = nil
+        @allow_remote = true
+      end
+
+      def cached!
+        @allow_cached = true
+      end
+
+      def hash
+        @remotes.hash
+      end
+
+      def eql?(other)
+        other.is_a?(Rubygems) && other.credless_remotes == credless_remotes
+      end
+
+      alias_method :==, :eql?
+
+      def include?(o)
+        o.is_a?(Rubygems) && (o.credless_remotes - credless_remotes).empty?
+      end
+
+      def can_lock?(spec)
+        spec.source.is_a?(Rubygems)
+      end
+
+      def options
+        { "remotes" => @remotes.map(&:to_s) }
+      end
+
+      def self.from_lock(options)
+        new(options)
+      end
+
+      def to_lock
+        out = String.new("GEM\n")
+        remotes.reverse_each do |remote|
+          out << "  remote: #{suppress_configured_credentials remote}\n"
+        end
+        out << "  specs:\n"
+      end
+
+      def to_s
+        remote_names = remotes.map(&:to_s).join(", ")
+        "rubygems repository #{remote_names}"
+      end
+      alias_method :name, :to_s
+
+      def specs
+        @specs ||= begin
+          # remote_specs usually generates a way larger Index than the other
+          # sources, and large_idx.use small_idx is way faster than
+          # small_idx.use large_idx.
+          idx = @allow_remote ? remote_specs.dup : Index.new
+          idx.use(cached_specs, :override_dupes) if @allow_cached || @allow_remote
+          idx.use(installed_specs, :override_dupes)
+          idx
+        end
+      end
+
+      def install(spec, opts = {})
+        force = opts[:force]
+        ensure_builtin_gems_cached = opts[:ensure_builtin_gems_cached]
+
+        if ensure_builtin_gems_cached && builtin_gem?(spec)
+          if !cached_path(spec)
+            cached_built_in_gem(spec) unless spec.remote
+            force = true
+          else
+            spec.loaded_from = loaded_from(spec)
+          end
+        end
+
+        if installed?(spec) && (!force || spec.name.eql?("bundler"))
+          Bundler.ui.info "Using #{version_message(spec)}"
+          return nil # no post-install message
+        end
+
+        # Download the gem to get the spec, because some specs that are returned
+        # by rubygems.org are broken and wrong.
+        if spec.remote
+          # Check for this spec from other sources
+          uris = [spec.remote.anonymized_uri]
+          uris += remotes_for_spec(spec).map(&:anonymized_uri)
+          uris.uniq!
+          Installer.ambiguous_gems << [spec.name, *uris] if uris.length > 1
+
+          s = Bundler.rubygems.spec_from_gem(fetch_gem(spec), Bundler.settings["trust-policy"])
+          spec.__swap__(s)
+        end
+
+        unless Bundler.settings[:no_install]
+          message = "Installing #{version_message(spec)}"
+          message += " with native extensions" if spec.extensions.any?
+          Bundler.ui.confirm message
+
+          path = cached_gem(spec)
+          if requires_sudo?
+            install_path = Bundler.tmp(spec.full_name)
+            bin_path     = install_path.join("bin")
+          else
+            install_path = rubygems_dir
+            bin_path     = Bundler.system_bindir
+          end
+
+          installed_spec = nil
+          Bundler.rubygems.preserve_paths do
+            installed_spec = Bundler::RubyGemsGemInstaller.at(
+              path,
+              :install_dir         => install_path.to_s,
+              :bin_dir             => bin_path.to_s,
+              :ignore_dependencies => true,
+              :wrappers            => true,
+              :env_shebang         => true,
+              :build_args          => opts[:build_args],
+              :bundler_expected_checksum => spec.respond_to?(:checksum) && spec.checksum
+            ).install
+          end
+          spec.full_gem_path = installed_spec.full_gem_path
+
+          # SUDO HAX
+          if requires_sudo?
+            Bundler.rubygems.repository_subdirectories.each do |name|
+              src = File.join(install_path, name, "*")
+              dst = File.join(rubygems_dir, name)
+              if name == "extensions" && Dir.glob(src).any?
+                src = File.join(src, "*/*")
+                ext_src = Dir.glob(src).first
+                ext_src.gsub!(src[0..-6], "")
+                dst = File.dirname(File.join(dst, ext_src))
+              end
+              SharedHelpers.filesystem_access(dst) do |p|
+                Bundler.mkdir_p(p)
+              end
+              Bundler.sudo "cp -R #{src} #{dst}" if Dir[src].any?
+            end
+
+            spec.executables.each do |exe|
+              SharedHelpers.filesystem_access(Bundler.system_bindir) do |p|
+                Bundler.mkdir_p(p)
+              end
+              Bundler.sudo "cp -R #{install_path}/bin/#{exe} #{Bundler.system_bindir}/"
+            end
+          end
+          installed_spec.loaded_from = loaded_from(spec)
+        end
+        spec.loaded_from = loaded_from(spec)
+
+        spec.post_install_message
+      ensure
+        Bundler.rm_rf(install_path) if requires_sudo?
+      end
+
+      def cache(spec, custom_path = nil)
+        if builtin_gem?(spec)
+          cached_path = cached_built_in_gem(spec)
+        else
+          cached_path = cached_gem(spec)
+        end
+        raise GemNotFound, "Missing gem file '#{spec.full_name}.gem'." unless cached_path
+        return if File.dirname(cached_path) == Bundler.app_cache.to_s
+        Bundler.ui.info "  * #{File.basename(cached_path)}"
+        FileUtils.cp(cached_path, Bundler.app_cache(custom_path))
+      rescue Errno::EACCES => e
+        Bundler.ui.debug(e)
+        raise InstallError, e.message
+      end
+
+      def cached_built_in_gem(spec)
+        cached_path = cached_path(spec)
+        if cached_path.nil?
+          remote_spec = remote_specs.search(spec).first
+          if remote_spec
+            cached_path = fetch_gem(remote_spec)
+          else
+            Bundler.ui.warn "#{spec.full_name} is built in to Ruby, and can't be cached because your Gemfile doesn't have any sources that contain it."
+          end
+        end
+        cached_path
+      end
+
+      def add_remote(source)
+        uri = normalize_uri(source)
+        @remotes.unshift(uri) unless @remotes.include?(uri)
+      end
+
+      def replace_remotes(other_remotes)
+        return false if other_remotes == @remotes
+
+        @remotes = []
+        other_remotes.reverse_each do |r|
+          add_remote r.to_s
+        end
+      end
+
+      def unmet_deps
+        if @allow_remote && api_fetchers.any?
+          remote_specs.unmet_dependency_names
+        else
+          []
+        end
+      end
+
+      def fetchers
+        @fetchers ||= remotes.map do |uri|
+          remote = Source::Rubygems::Remote.new(uri)
+          Bundler::Fetcher.new(remote)
+        end
+      end
+
+    protected
+
+      def credless_remotes
+        remotes.map(&method(:suppress_configured_credentials))
+      end
+
+      def remotes_for_spec(spec)
+        specs.search_all(spec.name).inject([]) do |uris, s|
+          uris << s.remote if s.remote
+          uris
+        end
+      end
+
+      def loaded_from(spec)
+        "#{rubygems_dir}/specifications/#{spec.full_name}.gemspec"
+      end
+
+      def cached_gem(spec)
+        cached_gem = cached_path(spec)
+        unless cached_gem
+          raise Bundler::GemNotFound, "Could not find #{spec.file_name} for installation"
+        end
+        cached_gem
+      end
+
+      def cached_path(spec)
+        possibilities = @caches.map {|p| "#{p}/#{spec.file_name}" }
+        possibilities.find {|p| File.exist?(p) }
+      end
+
+      def normalize_uri(uri)
+        uri = uri.to_s
+        uri = "#{uri}/" unless uri =~ %r{/$}
+        uri = URI(uri)
+        raise ArgumentError, "The source must be an absolute URI. For example:\n" \
+          "source 'https://rubygems.org'" if !uri.absolute? || (uri.is_a?(URI::HTTP) && uri.host.nil?)
+        uri
+      end
+
+      def suppress_configured_credentials(remote)
+        remote_nouser = remote.dup.tap {|uri| uri.user = uri.password = nil }.to_s
+        if remote.userinfo && remote.userinfo == Bundler.settings[remote_nouser]
+          remote_nouser
+        else
+          remote
+        end
+      end
+
+      def installed_specs
+        @installed_specs ||= begin
+          idx = Index.new
+          have_bundler = false
+          Bundler.rubygems.all_specs.reverse_each do |spec|
+            if spec.name == "bundler"
+              next unless spec.version.to_s == VERSION
+              have_bundler = true
+            end
+            spec.source = self
+            if Bundler.rubygems.spec_missing_extensions?(spec, false)
+              Bundler.ui.debug "Source #{self} is ignoring #{spec} because it is missing extensions"
+              next
+            end
+            idx << spec
+          end
+
+          # Always have bundler locally
+          unless have_bundler
+            # We're running bundler directly from the source
+            # so, let's create a fake gemspec for it (it's a path)
+            # gemspec
+            bundler = Gem::Specification.new do |s|
+              s.name     = "bundler"
+              s.version  = VERSION
+              s.platform = Gem::Platform::RUBY
+              s.source   = self
+              s.authors  = ["bundler team"]
+              s.loaded_from = File.expand_path("..", __FILE__)
+            end
+            idx << bundler
+          end
+          idx
+        end
+      end
+
+      def cached_specs
+        @cached_specs ||= begin
+          idx = installed_specs.dup
+
+          Dir["#{cache_path}/*.gem"].each do |gemfile|
+            next if gemfile =~ /^bundler\-[\d\.]+?\.gem/
+            s ||= Bundler.rubygems.spec_from_gem(gemfile)
+            s.source = self
+            if Bundler.rubygems.spec_missing_extensions?(s, false)
+              Bundler.ui.debug "Source #{self} is ignoring #{s} because it is missing extensions"
+              next
+            end
+            idx << s
+          end
+        end
+
+        idx
+      end
+
+      def api_fetchers
+        fetchers.select {|f| f.use_api && f.fetchers.first.api_fetcher? }
+      end
+
+      def remote_specs
+        @remote_specs ||= Index.build do |idx|
+          index_fetchers = fetchers - api_fetchers
+
+          # gather lists from non-api sites
+          index_fetchers.each do |f|
+            Bundler.ui.info "Fetching source index from #{f.uri}"
+            idx.use f.specs_with_retry(nil, self)
+          end
+
+          # because ensuring we have all the gems we need involves downloading
+          # the gemspecs of those gems, if the non-api sites contain more than
+          # about 100 gems, we treat all sites as non-api for speed.
+          allow_api = idx.size < API_REQUEST_LIMIT && dependency_names.size < API_REQUEST_LIMIT
+          Bundler.ui.debug "Need to query more than #{API_REQUEST_LIMIT} gems." \
+            " Downloading full index instead..." unless allow_api
+
+          if allow_api
+            api_fetchers.each do |f|
+              Bundler.ui.info "Fetching gem metadata from #{f.uri}", Bundler.ui.debug?
+              idx.use f.specs_with_retry(dependency_names, self)
+              Bundler.ui.info "" unless Bundler.ui.debug? # new line now that the dots are over
+            end
+
+            # Suppose the gem Foo depends on the gem Bar.  Foo exists in Source A.  Bar has some versions that exist in both
+            # sources A and B.  At this point, the API request will have found all the versions of Bar in source A,
+            # but will not have found any versions of Bar from source B, which is a problem if the requested version
+            # of Foo specifically depends on a version of Bar that is only found in source B. This ensures that for
+            # each spec we found, we add all possible versions from all sources to the index.
+            loop do
+              idxcount = idx.size
+              api_fetchers.each do |f|
+                Bundler.ui.info "Fetching version metadata from #{f.uri}", Bundler.ui.debug?
+                idx.use f.specs_with_retry(idx.dependency_names, self), true
+                Bundler.ui.info "" unless Bundler.ui.debug? # new line now that the dots are over
+              end
+              break if idxcount == idx.size
+            end
+
+            if api_fetchers.any?
+              # it's possible that gems from one source depend on gems from some
+              # other source, so now we download gemspecs and iterate over those
+              # dependencies, looking for gems we don't have info on yet.
+              unmet = idx.unmet_dependency_names
+
+              # if there are any cross-site gems we missed, get them now
+              api_fetchers.each do |f|
+                Bundler.ui.info "Fetching dependency metadata from #{f.uri}", Bundler.ui.debug?
+                idx.use f.specs_with_retry(unmet, self)
+                Bundler.ui.info "" unless Bundler.ui.debug? # new line now that the dots are over
+              end if unmet.any?
+            else
+              allow_api = false
+            end
+          end
+
+          unless allow_api
+            api_fetchers.each do |f|
+              Bundler.ui.info "Fetching source index from #{f.uri}"
+              idx.use f.specs_with_retry(nil, self)
+            end
+          end
+        end
+      end
+
+      def fetch_gem(spec)
+        return false unless spec.remote
+        uri = spec.remote.uri
+        spec.fetch_platform
+        Bundler.ui.confirm("Fetching #{version_message(spec)}")
+
+        download_path = requires_sudo? ? Bundler.tmp(spec.full_name) : rubygems_dir
+        gem_path = "#{rubygems_dir}/cache/#{spec.full_name}.gem"
+
+        SharedHelpers.filesystem_access("#{download_path}/cache") do |p|
+          FileUtils.mkdir_p(p)
+        end
+        Bundler.rubygems.download_gem(spec, uri, download_path)
+
+        if requires_sudo?
+          SharedHelpers.filesystem_access("#{rubygems_dir}/cache") do |p|
+            Bundler.mkdir_p(p)
+          end
+          Bundler.sudo "mv #{download_path}/cache/#{spec.full_name}.gem #{gem_path}"
+        end
+
+        gem_path
+      ensure
+        Bundler.rm_rf(download_path) if requires_sudo?
+      end
+
+      def builtin_gem?(spec)
+        # Ruby 2.1, where all included gems have this summary
+        return true if spec.summary =~ /is bundled with Ruby/
+
+        # Ruby 2.0, where gemspecs are stored in specifications/default/
+        spec.loaded_from && spec.loaded_from.include?("specifications/default/")
+      end
+
+      def installed?(spec)
+        installed_specs[spec].any?
+      end
+
+      def requires_sudo?
+        Bundler.requires_sudo?
+      end
+
+      def rubygems_dir
+        Bundler.rubygems.gem_dir
+      end
+
+      def cache_path
+        Bundler.app_cache
+      end
+    end
+  end
+end
diff --git a/lib/bundler/source/rubygems/remote.rb b/lib/bundler/source/rubygems/remote.rb
new file mode 100644
index 0000000000..b49e645506
--- /dev/null
+++ b/lib/bundler/source/rubygems/remote.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+module Bundler
+  class Source
+    class Rubygems
+      class Remote
+        attr_reader :uri, :anonymized_uri, :original_uri
+
+        def initialize(uri)
+          orig_uri = uri
+          uri = Bundler.settings.mirror_for(uri)
+          @original_uri = orig_uri if orig_uri != uri
+          fallback_auth = Bundler.settings.credentials_for(uri)
+
+          @uri = apply_auth(uri, fallback_auth).freeze
+          @anonymized_uri = remove_auth(@uri).freeze
+        end
+
+        # @return [String] A slug suitable for use as a cache key for this
+        #         remote.
+        #
+        def cache_slug
+          @cache_slug ||= begin
+            cache_uri = original_uri || uri
+
+            uri_parts = [cache_uri.host, cache_uri.user, cache_uri.port, cache_uri.path]
+            uri_digest = Digest::MD5.hexdigest(uri_parts.compact.join("."))
+
+            uri_parts[-1] = uri_digest
+            uri_parts.compact.join(".")
+          end
+        end
+
+        def to_s
+          "rubygems remote at #{anonymized_uri}"
+        end
+
+      private
+
+        def apply_auth(uri, auth)
+          if auth && uri.userinfo.nil?
+            uri = uri.dup
+            uri.userinfo = auth
+          end
+
+          uri
+        rescue URI::InvalidComponentError
+          error_message = "Please CGI escape your usernames and passwords before " \
+                          "setting them for authentication."
+          raise HTTPError.new(error_message)
+        end
+
+        def remove_auth(uri)
+          if uri.userinfo
+            uri = uri.dup
+            uri.user = uri.password = nil
+          end
+
+          uri
+        end
+      end
+    end
+  end
+end