Re: [GIT PULL] xfs: updates for 3.18-rc1

From: Dave Chinner
Date: Mon Oct 13 2014 - 17:56:05 EST

On Mon, Oct 13, 2014 at 05:48:18AM -0400, Linus Torvalds wrote:
> On Sun, Oct 12, 2014 at 9:37 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> >
> > i.e. I have generated this pull-req from the base tree I've been working
> > on (3.17-rc2) but there have already been commits merged into a more
> > recent upstream tree (3.17-rc4) in this tree. When I generate the
> > pull request from the underlying 3.17-rc2 branch, it includes all
> > those commits, both in the summary and the diffstat. If I base the
> > pull request off 3.17, the base commit is the last one that was
> > merged into your tree, and the diffstat and commit list reflect
> > that.
> That's fine, and works for me too. This is normal and expected for
> stuff that has gotten into my tree other ways (ie bugfixes that were
> cherrypicked to be backported from development trees etc). I'm used
> to it, and while I hope people minimize it (not only because of
> multiple commits showing up with the same patch, but because it can
> easily cause stupid merge conflicts because the development tree then
> made further changes on top of the same patch), it's also very much
> considered "normal development".
> That said, when there are actual *common* commits as in your case (as
> opposed to cherrypicked commits that generate duplicate commits with
> the same patch), I would generally suggest you just let "git
> merge-base" figure it all out from my latest tree. That way it takes
> into account the stuff that you sent earlier on its own.

Ok, that seems easy enough to check. I wasn't aware of git
merge-base, so thanks for letting me know about it.

> But this is not a big deal.
> > So my question is this: Which tree should I generate the pull
> > request from? I flipped a coin an generated this one from 3.17-rc2,
> > but if you'd prefer to see just the commits/diffstat that aren't in
> > your tree, let me know and I'll do it differently next time....
> Normally, I'd suggest the easiest way to handle things is to have a
> "linus" branch that tracks my upstream, and then just generate the
> pull request off that. Git will figure out the latest merge base and
> just do the right thing, and you don't need to really think about
> where you forked things off, and which parts you have already sent to
> me.

OK, that's exactly what I would have done if the coin flip landed
the other way. I'll use that method in future.

> As mentioned, even then the diffstat doesn't always end up being
> exactly right, because the history with partially merged branches, and
> with potential cherry-picked commits. So I am not surprised or upset
> if the diffstat doesn't always match, it happens quite commonly. I go
> on a rant when that i sdue to bad development practices, but I don't
> see anything like that in your tree.

That's good to know - I'm trying to keep the topic branches as
stable as possible so you can see when they were first pushed into
the tree, if/when fixes are appended to them and the dependencies
between them so bisects won't break. If you do see something wrong
or dodgy, just yell. ;)

> Some people avoid this by actually generating a test-merge (to warn me
> about upcoming conflicts etc), and then generate the diffstat from
> that test merge instead of just using the plain "git diff" in the
> git-pull-request helper scripts. Whatever works. This is not a huge
> deal, exactly because it's "normal development" (unlike the
> back-merges issue).


Definitely "normal development" - I do that "test merge" as part of
my day-to-day workflow. My test tree (i.e. what I point overnight
xfstests runs at) is your TOT + the current XFS for-next + any patch
sets I'm reviewing, testing and/or developing....

Thanks for the info, Linus.


Dave Chinner
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