<!-- This template is a great use for issues that are feature::additions or technical tasks for larger issues.--> ### Context Include information about the [merged results pipeline](https://docs.gitlab.com/ee/ci/pipelines/pipelines_for_merged_results.html) in the [merge request webhook event](https://docs.gitlab.com/ee/user/project/integrations/webhook_events.html#merge-request-events). When a project has merged results pipeline enabled the resulting merge request pipeline is run with a commit hash resulting from merging the source branch into the target branch and thus the commit seen by tools running inside the runner is not "real" in that it is the proposed commit hash if the MR were to be merged. This an important detail for applications integrating with GitLab's merge request webhooks must have. Without the details about the merged results pipeline in the merge request webhook event there is no way for applications that listen to webhooks to correlate the pipeline executions. Ideally this is part of the Epic https://gitlab.com/groups/gitlab-org/-/epics/5147 that is tracking various Merge Request Webhook improvements. I should also mention that I came across https://gitlab.com/gitlab-org/gitlab/-/issues/225597 which is part of the aforementioned epic. So maybe the details are already in the event but just not documented? <!-- Label reminders Use the following resources to find the appropriate labels: - https://gitlab.com/gitlab-org/gitlab/-/labels - https://about.gitlab.com/handbook/product/categories/features/ --> #### Current workaround Use the [API to get the branches for a commit](https://docs.gitlab.com/ee/api/commits.html#get-references-a-commit-is-pushed-to) and see if they follow [this pattern](https://gitlab.com/gitlab-org/gitlab/-/blob/8df4fa8ed3b502aa02367af434a1371b32c8c3b3/app/models/merge_request.rb#L1432-1435). See https://gitlab.com/gitlab-org/gitlab/-/issues/350086#note_822077692 ### Proposal Add a new property alongside the "real" last commit ID (see `object_attributes.last_commit.id`). Nest it under the `object_attributes.last_commit` object as `merged_results_id`: ```json { "object_attributes": { "last_commit": { "id": "SHA", "merged_results_id": "FAKESHA or null if not a merged results pipeline" } } } ``` See https://gitlab.com/gitlab-org/gitlab/-/issues/350086#note_820114711