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From: Jeff King <peff@peff.net>
To: Lars Schneider <larsxschneider@gmail.com>
Cc: Git List <git@vger.kernel.org>
Subject: Re: How to debug a "git merge"?
Date: Wed, 14 Mar 2018 18:20:29 -0400	[thread overview]
Message-ID: <20180314222028.GA20977@sigill.intra.peff.net> (raw)
In-Reply-To: <7895279B-9FB6-471B-A8BA-53315B265A51@gmail.com>

On Wed, Mar 14, 2018 at 05:56:04PM +0100, Lars Schneider wrote:

> I am investigating a Git merge (a86dd40fe) in which an older version of 
> a file won over the newer version. I try to understand why this is the 
> case. I can reproduce the merge with the following commands:
> $ git checkout -b test a02fa3303
> $ GIT_MERGE_VERBOSITY=5 git merge --verbose c1b82995c
> 
> The merge actually generates a merge conflict but not for my
> problematic file. The common ancestor of the two parents (merge base) 
> is b91161554.
> 
> The merge graph is not pretty (the committers don't have a clean 
> branching scheme) but I cannot spot a problem between the merge commit
> and the common ancestor:
> $ git log --graph --oneline a86dd40fe
> 
> Can you give me a hint how to debug this merge further? How can I 
> understand why Git picked a certain version of a file in a merge?

Maybe a stupid question, but: did you make sure that the merge does
indeed pick the wrong version of the file? The other option is that
somebody mistakenly did a "checkout --ours" or similar while resolving
the conflict.

If the wrong file is indeed picked by the merge, then you may want to
try switching merge drivers. E.g., "-s resolve" is a bit simpler and
stupider than the default merge-recursive. If the problem goes away,
then we know it's a possible bug in merge-recursive (or maybe a
confusing implication of its strategy). If the problem is still there
with "resolve", then at least it may be easier to debug. ;)

-Peff

  parent reply	other threads:[~2018-03-14 22:20 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-14 16:56 How to debug a "git merge"? Lars Schneider
2018-03-14 17:02 ` Derrick Stolee
2018-03-14 20:53   ` Lars Schneider
2018-03-20  1:32     ` Derrick Stolee
2018-03-14 22:20 ` Jeff King [this message]
2018-03-15  9:51   ` Lars Schneider
2018-03-15 14:09     ` Jeff King
2018-03-15 15:51       ` Elijah Newren

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