[Insight-developers] Gerrit, Git, aliases and squashing commits

[Marcus D. Hanwell]

Hi,

I was going through some of the instructions on the ITK community concerning
Gerrit and staging changes. I will talk more about this at the ITK meeting
in November, but I don't think you should be squashing commits before
sending them to Gerrit unless you also intend to merge them into ITK in that
form. Gerrit is offering us review of commits before they go into our
repository, and the opportunity to fix these commits before they are merged.

If you think there are too many micro-commits to push to Gerrit then I would
argue there are too many to push into our repository. The whole point of
retaining history is so that people can also go in after the fact and review
previous commits for various reasons. Gerrit tracks the dependencies of
commits in a topic branch, you can look at a patch's dependencies and follow
needed-by until you reach the end of a topic branch. You can then copy/paste
the checkout line, and even make it into a local topic branch with the same
name,

git fetch http://review.source.kitware.com/p/ITK refs/changes/61/161/1 &&
git checkout FETCH_HEAD
git checkout -b GitAliases

Using the simple command line below you can see what commits you have that
are not yet merged into master,

git log --oneline --graph origin/master..

You can then compile and test these changes (if necessary), and even stage
this topic branch in the case of commits coming from the community. Using
the new aliases,

git stage-push

To merge the topic,

git stage-merge

Gerrit certainly needs some work to make topic branches simpler to deal with
in the interface, but this level of interaction is already possible. It is
how I work with Gerrit, and I have reviewed several lengthy topic branches
using this workflow. I also wanted to point out that if you have Change-Id
inserted as the last line of your commit message then,

git push stage HEAD:refs/for/master

Would be enough to update any commits you have changed on your topic branch,
as Gerrit uses the Change-Id lines to resolve the newly pushed commits to
the ones it has seen and update the patch sets accordingly. Thus, making it
very simple to push an updated topic branch and keep all dependencies
consistent.

Hopefully this makes a few things clearer, I will be listening out for any
more feedback/issues and look forward to meeting some of you at the ITK
meeting.

Marcus
--
Marcus D. Hanwell, Ph.D.
R&D Engineer, Kitware Inc.
(518) 881-4937
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/mailman/private/insight-developers/attachments/20101015/72aeed25/attachment.htm>