From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] combine-diff: handle --find-object in multitree code path
Date: Wed, 30 Sep 2020 15:07:15 -0700 [thread overview]
Message-ID: <xmqqmu16gbqk.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20200930115240.GA1899467@coredump.intra.peff.net> (Jeff King's message of "Wed, 30 Sep 2020 07:52:40 -0400")
Jeff King <peff@peff.net> writes:
> 2. It doesn't catch all cases where a particular path is interesting.
> Consider a merge with parent blobs X and Y for a particular path,
> and end result Z. That should be interesting according to "-c",
> because the result doesn't match either parent. And it should be
> interesting even with "--find-object=X", because "X" went away in
> the merge.
>
> But because we perform each pairwise diff independently, this
> confuses the intersection code. The change from X to Z is still
> interesting according to --find-object. But in the other parent we
> went from Y to Z, so the diff appears empty! That causes the
> intersection code to think that parent didn't change the path, and
> thus it's not interesting for "-c".
Hmmmm....
> +test_expect_success 'do not detect merge that does not touch blob' '
> + git checkout -B merge interesting &&
> + git merge -m "untouched blob" base &&
> + git diff-tree --format=%s --find-object=$blob -c --name-status HEAD >actual &&
You learn new things every day ;-)
I've always thought that for --find-object to do a good job, you'd
need "--full-history" and perhaps "-m". Especially, I didn't expect
"-c" or "--cc" to make a difference.
next prev parent reply other threads:[~2020-09-30 22:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 11:52 [PATCH] combine-diff: handle --find-object in multitree code path Jeff King
2020-09-30 20:06 ` Chris Torek
2020-09-30 22:46 ` Jeff King
2020-09-30 22:07 ` Junio C Hamano [this message]
2020-09-30 22:54 ` Jeff King
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