Re: showing conflicting merges

["Uwe Kleine-König" <Uwe.Kleine-Koenig@digi.com>]

Hello Santi,

Santi Béjar wrote:
> On Tue, Apr 22, 2008 at 11:12 AM, Uwe Kleine-König
> <Uwe.Kleine-Koenig@digi.com> wrote:
> > Hello,
> >
> >  There is a thread on the linux-arm-kernel ML that discusses handling of
> >  merge conflicts with git.[1]
> >
> >  I played around a bit with that and wondered about a few things:
> >
> >         ukleinek@zentaur:~/gsrc/linux-2.6$ git checkout -b test adf6d34e460387ee3e8f1e1875d
> >         Switched to a new branch "test"
> >
> >         ukleinek@zentaur:~/gsrc/linux-2.6$ git merge v2.6.25
> >         Auto-merged MAINTAINERS
> >         CONFLICT (delete/modify): drivers/leds/leds-tosa.c deleted in HEAD and modified in v2.6.25. Version v2.6.25 of drivers/leds/leds-tosa.c left in tree.
> >         Auto-merged drivers/serial/imx.c
> >         Automatic merge failed; fix conflicts and then commit the result.
> >
> >  Now "git diff --merge" shows:
> >
> >         diff --cc drivers/leds/leds-tosa.c
> >         index 7ebecc4,0000000..9e0a188
> >         ...
> >
> >  Shouldn't that better be reversed, i.e. 9e0a188..7ebecc4,0000000?
> 
> It compares the versions in conflict with the version in the working copy.

I have not checked in the source code, but the output of 

	strace -f -e open git diff --merge 2>&1 >/dev/null | grep leds-tosa

seems to contradict that (i.e. there is no output).

	7ebecc4 = v2.6.25:drivers/leds/leds-tosa.c
	9e0a188 = $(git merge-base test v2.6.25):drivers/leds/leds-tosa.c

(Ah, I just see, that's another hint that diff --merge doesn't look in
the working copy.  The wc has 7ebecc4 which is in the LHS together with
000000 (i.e. the deleted file from HEAD).

Maybe the combined diff format cannot have more than one rev on the RHS?

> >  The resolution was to delete drivers/leds/leds-tosa.c:
> >
> >         ukleinek@zentaur:~/gsrc/linux-2.6$ git rm drivers/leds/leds-tosa.c
> >         rm 'drivers/leds/leds-tosa.c'
> >         rm 'drivers/leds/leds-tosa.c'
> >
> >         ukleinek@zentaur:~/gsrc/linux-2.6$ git commit
> >         Created commit 99a64ab: Merge commit 'v2.6.25' into test
> >
> >  Now "git show" doesn't show the conflict resolution as it does for other
> >  conflicting merges.
> >  Adding -p and/or --cc didn't help either.  Looking at the source I think
> >  the problem is that diff_tree_combined only shows diffs for paths that
> >  are touched by every parent.  I'm not sure how I want to have the diff
> >  shown, but showing nothing seems wrong.  Ideas?
> 
> The combined diff does not show conflicts, it only shows the merged
> results that are different to all the parents. In this case the merge
> resolution is to delete one file as in HEAD, so it won't be shown.
> 
> If you want to see the conflict resolution you have to recreate the
> merge and compare with the original merge.
An option to show would be great ...

Best regards
Uwe

-- 
Uwe Kleine-König, Software Engineer
Digi International GmbH Branch Breisach, Küferstrasse 8, 79206 Breisach, Germany
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