Specify squash messages in advance and retain them until merge

Problem to solve

We have feature branches where multiple people are working, and one or more gatekeepers who are in charge of approving the final merge.

Commits part of the feature branch often have one-liner commit messages which are not too descriptive.

We would like to be able to allow people to fill the squash commit message in advance so that it can also be reviewed before merging, and ensure better quality when looking at the history of the target branch. This should be persisted when leaving the page / reloading it.

An alternative is to allow prefilling the squash commit title and message content with the MR title and description. Note however that the MR and commit message might not want to contain the same information, so this is not the preferred solution.

Intended users

Developers and Maintainers.

User experience goal

Avoid having to copy-and-paste squash commit messages around. Treat the commit message as code / part of the commit itself, as it should, and thus subject to review by anyone visiting the MR.

Proposal

Make the squash commit message an available field even if the MR is not directly mergeable, as a collapsible field.

Persist its contents across page visits.