Github's conflict resolution creates merge conflicts that are then flagged by rustbot

[safinaskar]

This repo is probably misconfigured: merge commits probably are allowed in the repo's settings.

Recently I submitted this PR: #136471 . Github shows me so-called "new PR merge experience" ( https://github.com/orgs/community/discussions/143787 ). At some point Github detected a conflict between my branch and mainline and showed me a message about this. Github interface offered me to fix this conflict directly in Github interface. I agreed and fixed (in Github web interface). But then immediately @rustbot said me that merges are not allowed. So I have to remove my merge commit and do rebase instead on my computer locally.

So, for unknown reasons Github offers a user to create merge commit, despite they are not allowed. This is probably repo misconfiguration. If there is no misconfiguration, then this is a bug in Github's "new PR merge experience" and should be reported to https://github.com/orgs/community/discussions/143787 .

I consider this a high-priority bug, because it presents a major contribution roadblock. This will definitely scary away potential contributors. Think about this: at first you are asked to do a merge, but then immediately @rustbot says to you that you did something wrong and should undo. I think many potential contributor will simply think: "I don't want to contribute at all".

@rustbot label T-infra A-contributor-roadblock P-high

[rustbot]

Error: Label P-high can only be set by Rust team members

Please file an issue on GitHub at triagebot if there's a problem with this bot, or reach out on #t-infra on Zulip.

[safinaskar]

@rustbot label T-infra A-contributor-roadblock

[RalfJung]

Note that we do have some PRs where merge commits are allowed and even required, such as subtree syncs. So any repo setting that forbids merge commits entirely does not work for us. So I don't think there is a misconfiguration here.

So if Github only offers "forbid merge commits entirely" and "direct users to resolve conflicts by adding merge commits", then neither option works for us and this should be reported with Github. (I have no idea if the "new merge experience" changes anything here.)

[rustbot]

Error: Label P-high can only be set by Rust team members

Please file an issue on GitHub at triagebot if there's a problem with this bot, or reach out on #t-infra on Zulip.