Add support for custom branches in ENV["RGV"]

spec/rubygems/rubygems.rb

@@ -2,7 +2,7 @@
 
 require_relative "../support/rubygems_version_manager"
 
-RubygemsVersionManager.new(ENV["RGV"]).switch
+RubygemsVersionManager.new(ENV["RGV"]).prepare
 
 $:.delete("#{Spec::Path.spec_dir}/rubygems")
 

spec/support/rubygems_ext.rb

@@ -76,6 +76,9 @@ def setup
 
       require "rubygems/user_interaction"
       Gem::DefaultUserInteraction.ui = Gem::SilentUI.new
+
+      require_relative "rubygems_version_manager"
+      RubygemsVersionManager.new(ENV["RGV"]).switch
     end
 
   private

spec/support/rubygems_version_manager.rb

@@ -15,9 +15,13 @@ def initialize(env_version)
   def switch
     return if use_system?
 
-    unrequire_rubygems_if_needed
-
     switch_local_copy_if_needed
+  end
+
+  def prepare
+    return if use_system?
+
+    unrequire_rubygems_if_needed
 
     prepare_environment
   end
@@ -56,21 +60,23 @@ def prepare_environment
   end
 
   def rubygems_unrequire_needed?
-    defined?(Gem::VERSION) && Gem::VERSION != target_gem_version
+    defined?(Gem::VERSION) && Gem::VERSION != local_copy_version
   end
 
   def local_copy_switch_needed?
-    !env_version_is_path? && target_gem_version != local_copy_version
-  end
-
-  def target_gem_version
-    @target_gem_version ||= resolve_target_gem_version
+    !env_version_is_path? && target_tag_version != local_copy_tag
   end
 
   def target_tag_version
     @target_tag_version ||= resolve_target_tag_version
   end
 
+  def local_copy_tag
+    Dir.chdir(local_copy_path) do
+      sys_exec!("git rev-parse --abbrev-ref HEAD")
+    end
+  end
+
   def local_copy_version
     gemspec_contents = File.read(local_copy_path.join("lib/rubygems.rb"))
     version_regexp = /VERSION = ["'](.*)["']/
@@ -106,22 +112,6 @@ def expanded_env_version
   def resolve_target_tag_version
     return "v#{@env_version}" if @env_version.match(/^\d/)
 
-    return "master" if @env_version == master_gem_version
-
     @env_version
   end
-
-  def resolve_target_gem_version
-    return local_copy_version if env_version_is_path?
-
-    return @env_version[1..-1] if @env_version.match(/^v/)
-
-    return master_gem_version if @env_version == "master"
-
-    @env_version
-  end
-
-  def master_gem_version
-    "3.1.0.pre1"
-  end
 end