## 🧩 Problem statement Today, when users enable merge train(after enabling pipeline for merged results), `Merge immediately` always shows up. Enabling pipeline must succeed only takes into account the recent pipeline(pipeline for merged results) and not the pipeline for merge train. Users see a `Merge immediately` button even after the pipeline for merged results has succeeded which in reality is an option to merge without adding to the train. ## 💬 Background discussion * https://gitlab.com/gitlab-org/gitlab/-/issues/320981#note_578018148 * [2022-01-17 Current status video](https://www.youtube.com/watch?v=Jyv42z_3yiM) ## 📝 New proposed solution + expected behavior By adding an additional toggle, users would get an option if they want the recent pipeline to be considered or specifically the pipeline for merge trains. Toggle on ------- - [x] **Only allow merging via merge train** When enabled, the **Merge immediately** option is not available in merge requests. All merge requests must be added to a merge train to merge. ------- 1. Merged Result pipeline is running :runner: - Only 'Start the train' is shown. 1. Merged Result pipeline passes :white_check_mark: - Only 'Start the train' is shown. 1. Train is started and new pipeline is running :runner: - no buttons 1. Merged Result pipeline is running for MR 2 :runner: - Only 'Add to the train' is shown. 1. Merged Result pipeline passes for MR 2 :white_check_mark: - Only 'Add to the train' is shown. 1. MR is added to train and new pipeline is running for MR 2 :runner: - no buttons Toggle off ------- - [ ] **Only allow merging via merge train** When enabled, the **Merge immediately** option is not available in merge requests. All merge requests must be added to a merge train to merge. ------- 1. Merged Result pipeline is running :runner: - Only 'Start the train' is shown. 1. **Merged Result pipeline passes :white_check_mark: - 'Start the train' and `Skip merge train and merge` is shown.** 1. Train is started and new pipeline is running :runner: - no buttons 1. Merged Result pipeline is running for MR 2 :runner: - Only 'Add to the train' is shown. 1. Merged Result pipeline passes for MR 2 :white_check_mark: - Only 'Add to the train' is shown. 1. MR is added to train and new pipeline is running for MR 2 :runner: - no buttons ## 👣 Steps for implementation 1. Remove the line of code that forces 'merge immediately' to always show for merge train and add a toggle in the `Enable merge trains` section to `Disable skip merge train` 2. Change the `Merge Immediately` button to rightly communicate the action when merge train is enabled 3. Improve the copy for `Pipeline must succeed` section to reflect that enabling this option would take away teh `Merge immediately` functionality from all scenarios <details><summary> Old description</summary> ## Summary If `pipelines must succeed` is configured, MRs should only be merged if a pipeline has successfully run. However, this is not currently being enforced for pipelines for merged results when merge trains are enabled. If both of these features are on it is possible to click on 'merge immediately' and skip the "pipeline must succeed" protection, regardless of whether or not master is still at the ref that the pipeline validated. ([see also here](https://gitlab.com/gitlab-org/gitlab/-/issues/9186#note_161401013) and [here](https://gitlab.com/gitlab-org/gitlab/-/issues/9186#note_160209883)) ### Steps to reproduce * Be sure to configure `Pipelines for merged results` and `Pipelines must succeed`  * Create a branch and commit something * Open an MR to merge the branch to master * a pipeline will be started on the merged result and succeed * Start merge train / merge immediately will be available on the MR (correct behavior so far) * Push another change directly to master. Master will be advanced as compared to the MR pipeline. * Merge immediately is still available on the MR (**bug**) ### Example Project https://gitlab.com/mbruemmer/new-project ### What is the current *bug* behavior? * `Merge immediately` is available even though target branch is advanced ### What is the expected *correct* behavior? * `Merge immediately` is only available if the target branch is not advanced ### Relevant logs and/or screenshots  As seen in this screenshot, Master is ahead by 1 commit but I can still merge immediately, even though the pipeline for merged results is no outdated. ### Output of checks This bug happens on GitLab.com ### Possible fixes (If you can, link to the line of code that might be responsible for the problem) Check to make sure that the pipeline that succeeded against master is still valid before presenting "merge immediately". If master has advanced, clearly say why merging immediately is not possible. </details>