Update to ruby/mspec@4120a62

spec/mspec/tool/sync/sync-rubyspec.rb

@@ -157,12 +157,16 @@ def rebase_commits(impl)
   end
 end
 
+def new_commits?(impl)
+  Dir.chdir(SOURCE_REPO) do
+    diff = `git diff master #{impl.rebased_branch}`
+    !diff.empty?
+  end
+end
+
 def test_new_specs
   require "yaml"
   Dir.chdir(SOURCE_REPO) do
-    diff = `git diff master`
-    abort "#{BRIGHT_YELLOW}No new commits, aborting#{RESET}" if diff.empty?
-
     workflow = YAML.load_file(".github/workflows/ci.yml")
     job_name = MSPEC ? "test" : "specs"
     versions = workflow.dig("jobs", job_name, "strategy", "matrix", "ruby")
@@ -195,8 +199,8 @@ end
 def fast_forward_master(impl)
   Dir.chdir(SOURCE_REPO) do
     sh "git", "checkout", "master"
-    sh "git", "merge", "--ff-only", "#{impl.name}-rebased"
+    sh "git", "merge", "--ff-only", impl.rebased_branch
-    sh "git", "branch", "--delete", "#{impl.name}-rebased"
+    sh "git", "branch", "--delete", impl.rebased_branch
   end
 end
 
@@ -215,10 +219,15 @@ def main(impls)
     update_repo(impl)
     filter_commits(impl)
     rebase_commits(impl)
+    if new_commits?(impl)
       test_new_specs
       verify_commits(impl)
       fast_forward_master(impl)
       check_ci
+    else
+      STDERR.puts "#{BRIGHT_YELLOW}No new commits#{RESET}"
+      fast_forward_master(impl)
+    end
   end
 end