[rubygems/rubygems] Keep only the bare clone in the per app cache

We don't need an actual checkout since the cache path is no longer used
as the install location. Now the per app cache acts just like the
standard cache.

https://github.com/rubygems/rubygems/commit/686988923c

lib/bundler/runtime.rb

@@ -139,10 +139,6 @@ module Bundler
         spec.source.cache(spec, custom_path) if spec.source.respond_to?(:cache)
       end
 
-      Dir[cache_path.join("*/.git")].each do |git_dir|
-        FileUtils.touch(File.expand_path("../.bundlecache", git_dir))
-      end
-
       prune_cache(cache_path) unless Bundler.settings[:no_prune]
     end
 

lib/bundler/source/git.rb

@@ -222,7 +222,8 @@ module Bundler
         cached!
         FileUtils.rm_rf(app_cache_path)
         git_proxy.checkout if requires_checkout?
-        git_proxy.copy_to(app_cache_path, @submodules)
+        FileUtils.cp_r("#{cache_path}/.", app_cache_path)
+        FileUtils.touch(app_cache_path.join(".bundlecache"))
       end
 
       def load_spec_files

spec/bundler/cache/git_spec.rb

@@ -25,6 +25,7 @@ RSpec.describe "bundle cache with git" do
     bundle "config set cache_all true"
     bundle :cache
     expect(bundled_app("vendor/cache/foo-1.0-#{ref}")).to exist
+    expect(bundled_app("vendor/cache/foo-1.0-#{ref}/.git")).not_to exist
     expect(bundled_app("vendor/cache/foo-1.0-#{ref}/.bundlecache")).to be_file
 
     FileUtils.rm_rf lib_path("foo-1.0")
@@ -46,6 +47,7 @@ RSpec.describe "bundle cache with git" do
     bundle :cache
 
     expect(bundled_app("vendor/cache/foo-1.0-#{ref}")).to exist
+    expect(bundled_app("vendor/cache/foo-1.0-#{ref}/.git")).not_to exist
 
     FileUtils.rm_rf lib_path("foo-1.0")
     expect(the_bundle).to include_gems "foo 1.0"
@@ -209,7 +211,7 @@ RSpec.describe "bundle cache with git" do
     expect(the_bundle).to include_gem "foo 1.0"
   end
 
-  it "copies repository to vendor cache, including submodules" do
+  it "copies repository to vendor cache" do
     # CVE-2022-39253: https://lore.kernel.org/lkml/xmqq4jw1uku5.fsf@gitster.g/
     system(*%W[git config --global protocol.file.allow always])
 
@@ -234,7 +236,6 @@ RSpec.describe "bundle cache with git" do
     bundle :cache
 
     expect(bundled_app("vendor/cache/has_submodule-1.0-#{ref}")).to exist
-    expect(bundled_app("vendor/cache/has_submodule-1.0-#{ref}/submodule-1.0")).to exist
     expect(the_bundle).to include_gems "has_submodule 1.0"
   end