Editing a GitLab merge request

After creating a merge request and getting it reviewed by someone else, you often need to update it. You can access the merge request by clicking the link text (something like Merge request !4) and update the files.

If you did not create the fork, you may need to click the "Get push access" button after to  the "Issue fork project-3393112" text (above Merge request !4), if you get the warning "You don't have write access | You must have permission to edit files directly in this project."

Update all files in a merge request, in a single commit

When updating a merge request, instead of searching out the changed files one by one, and making several individual commits, it is also possible to open all changed files in a merge request, edit them, and make the changes in a single commit. This is useful, for example if you want to avoid launching many runs of the automated tests, and notices in the issue:

1. Click the link to a merge request, the link text will be something like Merge request !4.
2. Click the blue "Code" button in the upper right corner, you may have to click "Sign in" first.
3. Click "Open in Web IDE". The Web IDE will now open in a new tab, with all the changed files ready for further editing. The two columns show the diff, where left column is the original and right is the MR version. You make the updates in the right hand side window.
4. To edit additional files, open them from the left side file explorer. Since the file has not been changed, there will only be one column, and not two diff columns.
5. When you have made the desired updates, commit them by clicking the "Source Control" icon in the left hand side, adorned with a number that shows the number of pending changes.
   
6. Fill out the "Commit message" field and click the "Commit to ..." button below. It will prompt "You're committing your changes to the default branch ..." which is correct, even if it seems wrong.
7. After clicking "Continue" a new modal will say: "Success! Your changes have been committed", with a red button with the label "Go to MR".
8. Clicking that button takes you to the MR, were you can use the web IDE to confirm that your edit had been correctly committed to the existing MR.

The merge request should now be updated, and if you refresh the issue on drupal.org, the changes should pop up at the bottom, showing something like this:

Merge request !4 username updated 31 October 2023 at 10:27 # ✓ resolved

Updated patch to use dependency injection instead.

Accepting a suggested change

Another way to update a merge request, is accepting a suggested change to the MR made by a reviewer via GitLab's UI:

Suggest changes

Reviewers can suggest code changes with a Markdown syntax in merge request diff threads. The merge request author (or other users with the appropriate role) can apply any or all suggestions from the GitLab UI. Applying suggestions adds a commit to the merge request, authored by the user who suggested the changes.

A suggested change will be shown in the drupal.org issue as a comment followed by the text "Unresolved".

Follow the steps under Apply suggestions to apply the suggested changes to the merge request. Applying a suggestion also marks the suggestion as applied and resolves it.