Add a `has-conflicts` badge to PRs automatically

[ashmaroli]

GitHub status already reports a list of conflicts in a PR and disables merge as a consequence.
It'd be better if JekyllBot could piggyback on that status and automatically add a has-conflicts label to such PRs or use Jekyll's existing pending-resolution label.

[pathawks]

Maybe also add a comment to the PR letting the author/maintainers know that there are new conflicts that need to be resolved?

I'm not sure exactly how this would work though. Would every open PR need to be checked for conflicts each time a commit is added to master?

[ashmaroli]

Maybe also add a comment to the PR letting the author/maintainers know that there are new conflicts that need to be resolved?

That's a good idea. But I'm 👎 on it as its only going to leave behind Off-topic comments that the maintainers will have to manually minimize.. Instead, I favor the silent labeling. We, the maintainers then shout-out to the author if we're not able to resolve the conflicts ourselves (either from lack of branch-access, or from lack of time, or from lack of the know-how to best proceed further..)

Would every open PR need to be checked for conflicts each time a commit is added to master?

Yeah, that's how I vision it.. But how hard would it be for a Bot to traverse open PRs in reverse order and check for a conflict status from Github..? Definitely faster than a human doing the same, anyways.. 😛

[DirtyF]

We, the maintainers then shout-out to the author if we're not able to resolve the conflicts ourselves

👎 I'd rather minimize a comment than handle all conflicts.

[ashmaroli]

I'd rather minimize a comment that handle all conflicts.

Probably that's how the rest of team feels as well.. 👍

[DirtyF]

According to https://developer.github.com/v3/repos/merging/ @jekyllbot could add a label if a merge returns a Status: 409 Conflict

Maybe something to check in
https://github.com/parkr/auto-reply/blob/master/labeler/pending_rebase.go#L48

[parkr]

Yeah, checking if we get a 409 and adding some kind of unmergable label would be helpful feedback for maintainers, especially those using mobile. 📱