Do not push to repository if there was no change

Author: Jellby

marge/job.py

@@ -351,7 +351,9 @@ def update_from_target_branch_and_push(
                 start_commit='origin/' + target_branch,
             )
         branch_rewritten = True
-        repo.push_force(source_branch, source_repo_url)
+        source_sha = repo.get_commit_hash('source/' + source_branch)
+        if rewritten_sha != source_sha:
+            repo.push_force(source_branch, source_repo_url)
         changes_pushed = True
     except git.GitError:
         if not branch_updated: