[rfc] command to squash and merge

[sourcefrog]

It is common in the rust repo for at least small changes that reviewers ask the contributor to squash the changes before they're merged. (For example rust-lang/rust#38158 (comment).)

To avoid another round-trip to the contributor, perhaps Bors/Homu could be given a command to squash and merge, ie to do git commit --merge?

Looking at the code there seems to be a per-repo option for autosquash but Rust might want it to be per-PR.

[nox]

What would be the commit message?

[KiChjang]

FTR, we've been actually thinking of squashing PRs ourselves ever since maintainers gained the ability to push to/pull from PR branches.

[sourcefrog]

What would be the commit message?

I guess it would be the PR title, but perhaps it could be included in the command to Bors?

[Manishearth]

This also means that the PR won't get marked as merged unless homu first pushes the squashed version to the PR.

[sourcefrog]

True, which it probably cannot do when the PR is coming from a third party. However it could mark it as closed, and the author would presumably see the new commits in their name in their activity.

[sourcefrog]

Would it work for Homu to tell Github to do the merge (https://developer.github.com/v3/pulls/#merge-a-pull-request-merge-button)? There is a squash option there.

[Manishearth]

I ... guess. That's pretty incompatible with the current architecture. If github gave you a way of fetching the "post squash merge commit" that would be nice.

Then again, we already have support for rebasing (which just doesn't mark the PR as merged)

[nox]

A PR title isn't always a good commit message.

[asajeffrey]

We've also had cases of multi-author PRs, where we decided not to squash everything in order to preserve authorship.

[sourcefrog]

I'm not suggesting it should always squash. Just that, when the reviewer wants it squashed, Homu could do this, as a human reviewer would, rather than making the contributor do it. For new contributors it saves them getting into more complicated git commands: everything up to this point you could do entirely through the github web UI. And even for experienced users, it would save to find trips.

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On Tue, Dec 13, 2016, 5:59 PM Alan Jeffrey ***@***.***> wrote: We've also had cases of multi-author PRs, where we decided not to squash everything in order to preserve authorship. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#70 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAVI8wQ_1qKjCj0IDG7Oudj0KU6bGV-Lks5rH02HgaJpZM4LMULf> .

[asajeffrey]

Yes, having an option to automate "squash and r=me" would be nice, since we do it a lot.