Merge pull request #8307 from rubygems/segiddins/stop-storing-executable-names-in-ivars

Stop storing executable names in ivars

Author: segiddins

lib/rubygems/resolver/git_set.rb

@@ -36,7 +36,6 @@ class Gem::Resolver::GitSet < Gem::Resolver::Set
   def initialize # :nodoc:
     super()
 
-    @git             = ENV["git"] || "git"
     @need_submodules = {}
     @repositories    = {}
     @root_dir        = Gem.dir

lib/rubygems/source/git.rb

@@ -58,7 +58,6 @@ def initialize(name, repository, reference, submodules = false)
 
     @remote   = true
     @root_dir = Gem.dir
-    @git      = ENV["git"] || "git"
   end
 
   def <=>(other)
@@ -81,6 +80,10 @@ def ==(other) # :nodoc:
       @need_submodules == other.need_submodules
   end
 
+  def git_command
+    ENV.fetch("git", "git")
+  end
+
   ##
   # Checks out the files for the repository into the install_dir.
 
@@ -90,18 +93,18 @@ def checkout # :nodoc:
     return false unless File.exist? repo_cache_dir
 
     unless File.exist? install_dir
-      system @git, "clone", "--quiet", "--no-checkout",
+      system git_command, "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_command, "fetch", "--quiet", "--force", "--tags", install_dir
 
-      success = system @git, "reset", "--quiet", "--hard", rev_parse
+      success = system git_command, "reset", "--quiet", "--hard", rev_parse
 
       if @need_submodules
         require "open3"
-        _, status = Open3.capture2e(@git, "submodule", "update", "--quiet", "--init", "--recursive")
+        _, status = Open3.capture2e(git_command, "submodule", "update", "--quiet", "--init", "--recursive")
 
         success &&= status.success?
       end
@@ -118,11 +121,11 @@ def cache # :nodoc:
 
     if File.exist? repo_cache_dir
       Dir.chdir repo_cache_dir do
-        system @git, "fetch", "--quiet", "--force", "--tags",
+        system git_command, "fetch", "--quiet", "--force", "--tags",
                @repository, "refs/heads/*:refs/heads/*"
       end
     else
-      system @git, "clone", "--quiet", "--bare", "--no-hardlinks",
+      system git_command, "clone", "--quiet", "--bare", "--no-hardlinks",
              @repository, repo_cache_dir
     end
   end
@@ -182,7 +185,7 @@ def rev_parse # :nodoc:
     hash = nil
 
     Dir.chdir repo_cache_dir do
-      hash = Gem::Util.popen(@git, "rev-parse", @reference).strip
+      hash = Gem::Util.popen(git_command, "rev-parse", @reference).strip
     end
 
     raise Gem::Exception,