[ruby/rubygems] Run git operations in parallel (take 2):

- In ruby#9100, I opened a patch to run git operations in parallel in
  order to download git gems more quickly.
  The parallelization doesn't works when resolving is not needed due
  to a premature call to `source.specs` hit by this codepath.

  You can reproduce the problem and see that the gems aren't
  downloaded in parallel if you have an existing Gemfile and
  Gemfile.lock. (In my first patch, I forgot to try when a
  Gemfile.lock already existed).

  I'd like to introduce a new call to `prelad_git_sources`, when
  bundler hits the "missing specs" branch.
  I unforunately couldn't find a single place where we could preload
  git sources due to the `source.specs` that is called at different
  path.

ruby/rubygems@f25b40f21f

Author: Edouard-chin

lib/bundler/definition.rb

@@ -249,6 +249,7 @@ def removed_specs
     end
 
     def missing_specs
+      preload_git_sources
       resolve.missing_specs_for(requested_dependencies)
     end
 
@@ -1125,9 +1126,17 @@ def preload_git_source_worker
     end
 
     def preload_git_sources
-      needed_git_sources.each {|source| preload_git_source_worker.enq(source) }
-    ensure
-      preload_git_source_worker.stop
+      if Gem.ruby_version < Gem::Version.new("3.3")
+        # Ruby 3.2 has a bug that incorrectly triggers a circular dependency warning. This version will continue to
+        # fetch git repositories one by one.
+        return
+      end
+
+      begin
+        needed_git_sources.each {|source| preload_git_source_worker.enq(source) }
+      ensure
+        preload_git_source_worker.stop
+      end
     end
 
     # Git sources needed for the requested groups (excludes sources only used by --without groups)
@@ -1144,11 +1153,7 @@ def excluded_git_sources
     end
 
     def find_source_requirements
-      if Gem.ruby_version >= Gem::Version.new("3.3")
-        # Ruby 3.2 has a bug that incorrectly triggers a circular dependency warning. This version will continue to
-        # fetch git repositories one by one.
-        preload_git_sources
-      end
+      preload_git_sources
 
       # Record the specs available in each gem's source, so that those
       # specs will be available later when the resolver knows where to