[rubygems/rubygems] Allow gem exec gem

https://github.com/rubygems/rubygems/commit/a767f7b9be

lib/rubygems/commands/exec_command.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 require_relative "../command"
 require_relative "../dependency_installer"
+require_relative "../gem_runner"
 require_relative "../package"
 require_relative "../version_option"
 
@@ -60,7 +61,10 @@ to the same gem path as user-installed gems.
     check_executable
 
     print_command
-    if options[:conservative]
+    if options[:gem_name] == "gem" && options[:executable] == "gem"
+      Gem::GemRunner.new.run options[:args]
+      return
+    elsif options[:conservative]
       install_if_needed
     else
       install
@@ -135,15 +139,19 @@ to the same gem path as user-installed gems.
     activate!
   end
 
-  def install
-    gem_name = options[:gem_name]
-    gem_version = options[:version]
-
+  def set_gem_exec_install_paths
     home = File.join(Gem.dir, "gem_exec")
 
     ENV["GEM_PATH"] = ([home] + Gem.path).join(Gem.path_separator)
     ENV["GEM_HOME"] = home
     Gem.clear_paths
+  end
+
+  def install
+    set_gem_exec_install_paths
+
+    gem_name = options[:gem_name]
+    gem_version = options[:version]
 
     install_options = options.merge(
       minimal_deps: false,

test/rubygems/test_gem_commands_exec_command.rb

@@ -701,4 +701,45 @@ class TestGemCommandsExecCommand < Gem::TestCase
       assert_equal %w[b-2], @installed_specs.map(&:original_name)
     end
   end
+
+  def test_gem_exec_gem_uninstall
+    spec_fetcher do |fetcher|
+      fetcher.download "a", 2 do |s|
+        s.executables = %w[a]
+        s.files = %w[bin/a lib/a.rb]
+        s.add_runtime_dependency "b"
+
+        write_file File.join(*%W[gems #{s.original_name}      bin a]) do |f|
+          f << "Gem.ui.say #{s.original_name.dump}"
+        end
+      end
+
+      fetcher.download "b", 2 do |s|
+        s.files = %w[lib/b.rb]
+      end
+    end
+
+    use_ui @ui do
+      invoke "a:2"
+      assert_equal "a-2\n", @ui.output
+
+      invoke "gem", "list", "--local"
+      assert_includes @ui.output, "a (2)\n"
+      assert_includes @ui.output, "b (2)\n"
+
+      invoke "gem", "uninstall", "--verbose", "-x", "a" rescue nil
+      refute_includes @ui.output, "running gem exec with"
+      assert_includes @ui.output, "Successfully uninstalled a-2\n"
+
+      invoke "--verbose", "gem", "uninstall", "b"
+      assert_includes @ui.output, "Successfully uninstalled b-2\n"
+
+      invoke "gem", "list", "--local"
+      assert_empty @ui.error
+      assert_match /\A\s*\** LOCAL GEMS \**\s*\z/m, @ui.output
+
+      invoke "gem", "env", "GEM_HOME"
+      assert_match /#{File::SEPARATOR}gem_exec$/, @ui.output
+    end
+  end
 end