1 files changed, 21 insertions, 16 deletions

diff --git a/lib/rubygems/path_support.rb b/lib/rubygems/path_support.rb
index 618bc793c4..13091e29ba 100644
--- a/lib/rubygems/path_support.rb
+++ b/lib/rubygems/path_support.rb
@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+
 ##
 #
 # Gem::PathSupport facilitates the GEM_HOME and GEM_PATH environment settings
@@ -23,25 +24,26 @@ class Gem::PathSupport
   # hashtable, or defaults to ENV, the system environment.
   #
   def initialize(env)
-    @home     = env["GEM_HOME"] || Gem.default_dir
-
-    if File::ALT_SEPARATOR then
-      @home   = @home.gsub(File::ALT_SEPARATOR, File::SEPARATOR)
-    end
-
+    @home = normalize_home_dir(env["GEM_HOME"] || Gem.default_dir)
     @path = split_gem_path env["GEM_PATH"], @home
 
     @spec_cache_dir = env["GEM_SPEC_CACHE"] || Gem.default_spec_cache_dir
-
-    @spec_cache_dir = @spec_cache_dir.dup.untaint
   end
 
   private
 
+  def normalize_home_dir(home)
+    if File::ALT_SEPARATOR
+      home = home.gsub(File::ALT_SEPARATOR, File::SEPARATOR)
+    end
+
+    expand(home)
+  end
+
   ##
   # Split the Gem search path (as reported by Gem.path).
 
-  def split_gem_path gpaths, home
+  def split_gem_path(gpaths, home)
     # FIX: it should be [home, *path], not [*path, home]
 
     gem_path = []
@@ -50,11 +52,11 @@ class Gem::PathSupport
       gem_path = gpaths.split(Gem.path_separator)
       # Handle the path_separator being set to a regexp, which will cause
       # end_with? to error
-      if gpaths =~ /#{Gem.path_separator}\z/
+      if /#{Gem.path_separator}\z/.match?(gpaths)
         gem_path += default_path
       end
 
-      if File::ALT_SEPARATOR then
+      if File::ALT_SEPARATOR
         gem_path.map! do |this_path|
           this_path.gsub File::ALT_SEPARATOR, File::SEPARATOR
         end
@@ -65,16 +67,19 @@ class Gem::PathSupport
       gem_path = default_path
     end
 
-    gem_path.uniq
+    gem_path.map {|path| expand(path) }.uniq
   end
 
   # Return the default Gem path
   def default_path
-    gem_path = Gem.default_path + [@home]
+    Gem.default_path + [@home]
+  end
 
-    if defined?(APPLE_GEM_HOME)
-      gem_path << APPLE_GEM_HOME
+  def expand(path)
+    if File.directory?(path)
+      File.realpath(path)
+    else
+      path
     end
-    gem_path
   end
 end