Could margebot squash?

[Joachim Breitner]

Hi,

as far as I understand, the expected workflow for MRs is that when they
are ready, the developer manually squashes the chronological commit
history of the MR into a logical one with polished commit messages,
typically consisting of a single commit, but could be multiple ones,
and then assigns the MR to margebot, which will rebase that sequence of
commits onto the staging branch and eventually merges that into master.

One downside of this approach is that it requires destructive changes
to work-in-progres branches: I might think the MR is ready, squash the
commit sequence into a single commit, but then more work is ready. Now
it’s hard to revert individual patches, or collaborate with others,
because the git history was disrupted.

Another is that the commit message itself isn’t very easily visible to
reviewers.

In other similarly sized projects (e.g. mathlib) I often see a mode
where the actual commits of the MR are ignored (so they can represent
the true git history of the branch, including merges and all that grit,
which is good for collaboration and for reviewers to understand what
has happened, without requiring developers to spend cosmetics effort on
them), and upon merging by margebot/bors/mergify/whatever, the MR is
merged as a single commit with the description taken from the MR
description (which encourages developers to keep the MR description up
to date as the MR develops, reviewers can easily see that).

A downside of this that you’ll always get one commit on master per MR.
If you like to submit a curated list of logical commits within one MR,
then this would not work, and you’d have to use multiple MRs.


Has this been considered?

(I don’t want to cause unnecessary disruption with a presumptious call
for action here; take it as a comment to weigh in in if and when this
part of our infrastructure is about to change anyways, or maybe a
careful probe if my sentiment may be shared widely.)

Cheers,
Joachim


-- 
Joachim Breitner
  mail at joachim-breitner.de
  http://www.joachim-breitner.de/