Re: show all merge conflicts

From: Jeff King <peff@peff.net>
Date: Jan 28, 2017, 14:28 UTC
Message-ID: <20170128142808.hefnv7r3h6zidobw@sigill.intra.peff.net>
In-Reply-To: <CAAj3zPzO4+9t9_L2OXFmkihw-HwFvzybb7GXs4tTeFRyZHOaNQ@mail.gmail.com>

On Fri, Jan 27, 2017 at 09:42:41PM -0800, G. Sylvie Davies wrote:

Show 14 quoted lines

> Aside from the usual "git log -cc", I think this should work (replace
> HEAD with whichever commit you are analyzing):
> 
> git diff --name-only HEAD^2...HEAD^1 > m1
> git diff --name-only HEAD^1...HEAD^2 > b1
> git diff --name-only HEAD^1..HEAD    > m2
> git diff --name-only HEAD^2..HEAD    > b2
> 
> If files listed between m1 and b2 differ, then the merge is dirty.
> Similarly for m2 and b1.
> 
> More information here:
> 
> http://stackoverflow.com/questions/27683077/how-do-you-detect-an-evil-merge-in-git/41356308#41356308

I don't think that can reliably find evil merges, since it looks at the file level. If you had one hunk resolved for "theirs" and one hunk for "ours" in a given file, then the file will be listed in each diff, whether it has evil hunks or not.

I don't think this is just about evil merges, though. For instance, try:

  seq 1 10 >file
  git add file
  git commit -m base

  sed s/4/master/ <file >tmp && mv tmp file
  git commit -am master

  git checkout -b other HEAD^
  sed s/4/other/ <file >tmp && mv tmp file
  git commit -am other

  git merge master
  git checkout --ours file
  git commit -am merged

  merge=$(git rev-parse HEAD)

The question is: were there conflicts in $merge, and how were they resolved?

That isn't an evil merge, but there's still something interesting to show that "git log --cc" won't display.

Replaying the merge like:

  git checkout $merge^1
  git merge $merge^2
  git diff -R $merge

shows you the patch to go from the conflict state to the final one.

-Peff