Subject: Re: Test that every revision builds before pushing changes?

From: Andreas Ericsson <[email-masked]>
Date: Thu, 26 Mar 2009 09:16:37 +0100

Daniel Pittman wrote:
> G'day.
> 
> I would like to ensure that my commits are fully bisectable before I
> commit them to an upstream repository, at least to the limits of an
> automatic tool for testing them.
> 
> 'git bisect run' is similar: it can automatically locate the breaking in
> a test suite, for example, but that doesn't help me in the case of three
> commits, A (good), B (bad) and C (good, fixing B).
> 
> I would much rather, in this case, use rebase to fix B so that it, too,
> builds before I push the changes and pollute a public repository with a
> broken changeset — and make bisect that much harder to use in future.
> 

You can do that, but it requires manual work too. The trick is to make
the release branch immutable on the public repository and use topic
branches with per-developer namespaces. The per-developer namespace
thing is actually important, as it leaves the freedom to rewind and
recreate topics to the developers (which shared branches do not).

The manual step comes at merge-time; Someone has to be responsible for
merging all the topics that are to be included in the release branch
and make sure it builds and passes all tests after each merge.

This workflow is a bit cumbersome. NASA uses something like this but
with an extra step for multiple peer reviews on every feature/fix for
software they send to satellites. Or so I've heard anyways.

If you're thinking of a staging area that should queue all commits
and lock the repo while testing is in progress, you need to think
again, I'm afraid, as that locks up developer time in such huge
amounts that it isn't really worth it. Without the locking, you
get the problem of trying to automate merges (which may conflict
and need a manual resolution). Although I guess a merge conflict
could result in a delayed push error, so perhaps that could work
too. If you manage to cook up a solution for this, please make a
small writeup on this list how you went about achieving it.

-- 
Andreas Ericsson                   [email-masked]
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231

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