Re: breakage in revision traversal with pathspec

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 10, 2013, 22:23 UTC
Message-ID: <xmqq38pcwc21.fsf@gitster.dls.corp.google.com>
In-Reply-To: <522F8ED2.9000408@bracey.fi>

Kevin Bracey <kevin@bracey.fi> writes:

Show 19 quoted lines

> On 10/09/2013 20:19, Junio C Hamano wrote:
>> I am grumpy X-<.
>>
>> It appears that we introduced a large breakage during 1.8.4 cycle to
>> the revision traversal machinery and made pathspec-limited "git log"
>> pretty much useless.
>>
>> This command
>>
>>      $ git log v1.8.3.1..v1.8.4 -- git-cvsserver.perl
>>
>> reports that a merge 766f0f8ef7 (which did not touch the specified
>> path at all) touches it.
>>
>> Bisecting points at d0af663e (revision.c: Make --full-history
>> consider more merges, 2013-05-16).
>>
> That merge appearing *with* --full-history would seem like correct
> behaviour to me. Or at least it's what I intended.

Oh, of course. "--full-history" is about showing any pointless change, "the mainline was a lot more up-to-date and there were changes relative to a fork based on an older baseline", so your updated "log" should show that in the mainline git-cvsserver.perl has been more fresh when that merge happened. But it shouldn't appear if the user does not ask for "--full-history".

> However, your particular example occurs *without*--full-history, which
> suggests a problem.

Yes.

> I note that "gitk v1.8.3^0..v1.8.4" and "git log --parents
> v1.8.3..v1.8.4" show that merge in Git 1.8.3, but not in Git 1.8.4. So
> we're going partially forwards, at least.

With the testcases demonstrating the cases your series fixed that all look sensible, I think it is not really an option for us to revert them; you do not have to defend it with "we are going partially forwards" ;-).