Re: Improving merge of tricky conflicts

From: Jeff King <peff@peff.net>
Date: Jul 22, 2020, 07:45 UTC
Message-ID: <20200722074530.GB3306468@coredump.intra.peff.net>
In-Reply-To: <4df975f0-e4b1-afa1-cac1-f38e6d31a0d8@kdbg.org>

On Wed, Jul 22, 2020 at 07:50:08AM +0200, Johannes Sixt wrote:

Show 8 quoted lines

> Am 22.07.20 um 01:29 schrieb B. Stebler:
> > I have been looking for a tool to display merge conflicts, that instead
> > of showing the two versions of the conflicting section, would show the
> > diff for that section in both conflicting commits.
> 
> Perhaps you want to configure `merge.conflictStyle=diff3`? It does not
> exactly show a diff, but it writes the base version of the conflicted
> part in addition to "ours" and "theirs".

Yeah, I find diff3 is usually sufficient. But the contents of the base, "ours", and "theirs" sides are also available in the index:

  # diff between base (stage 1) and ours (stage 2)
  git diff :1:file :2:file

  # diff between base (stage 1) and theirs (stage 3)
  git diff :1:file :3:file

I thought we had added nice aliases for "ours" and "theirs" instead of the hard-to-remember stage numbers, but I think we only did so for things like "git checkout --ours", etc.

The big downside here, of course, is that it's showing the diff for the whole file, not just one hunk (on the other hand, I often find the trickiest conflicts are ones where the changes unexpectedly span multiple hunks).

There's also git-mergetool, which uses the information in those stages to feed content to other tools, which may show conflicts in more advanced ways. I don't have opinions on any of the particular tools it supports, but "git mergetool --tool-help" might be a good place to start exploring.

-Peff