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From: Lukas Fleischer <git@cryptocrack•de>
To: Junio C Hamano <gitster@pobox•com>
Cc: git@vger•kernel.org, Jeff King <peff@peff•net>
Subject: Re: [PATCH] blame.c: fix garbled error message
Date: Tue, 13 Jan 2015 00:18:49 +0100	[thread overview]
Message-ID: <20150112231849.4992.72982@typhoon.lan> (raw)
In-Reply-To: <xmqqzj9n623h.fsf@gitster.dls.corp.google.com>

On Mon, 12 Jan 2015 at 23:55:30, Junio C Hamano wrote:
> Junio C Hamano <gitster@pobox•com> writes:
> 
> > Lukas Fleischer <git@cryptocrack•de> writes:
> >
> >> The helper functions prepare_final() and prepare_initial() return a
> >> pointer to a string that is a member of an object in the revs->pending
> >> array. This array is later rebuilt when running prepare_revision_walk()
> >> which potentially transforms the pointer target into a bogus string. Fix
> >> this by maintaining a copy of the original string.
> >>
> >> Signed-off-by: Lukas Fleischer <git@cryptocrack•de>
> >> ---
> >> The bug manifests when running `git blame HEAD^ -- nonexistent.file`.
> >
> > Before 1da1e07c (clean up name allocation in prepare_revision_walk,
> > 2014-10-15), these strings used to be non-volatile; they were instead
> > leaked more or less deliberately.  But these days, these strings are
> > cleared, so your patch is absolutely the right thing to do.
> >
> > Thanks for catching and fixing.  This fix needs to go to the 2.2.x
> > maintenance track.
> 
> Sigh, but not so fast.
> 
> With the patch applied on top of 1da1e07c (or the result merged to
> 'next' for that matter), I see test breakages in many places "git
> blame" is used, e.g. t7010.  Did you run the test suite?
> 

No, I didn't.

> This is because it is perfectly normal for prepare_final() to return
> NULL.  Unconditionally running xstrdup() would of course fail.
> [...]

Something like

    return final_commit_name ? xstrdup(final_commit_name) : NULL;

should work, though, right? Calling free() with a null pointer is fine,
so there is nothing else to do here. You can either amend those two
lines or wait for me to resubmit v2 of the patch tomorrow :)

      parent reply	other threads:[~2015-01-12 23:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-10 21:33 [PATCH] blame.c: fix garbled error message Lukas Fleischer
2015-01-12 19:08 ` Junio C Hamano
2015-01-12 20:40   ` Jeff King
2015-01-12 22:55   ` Junio C Hamano
2015-01-12 23:12     ` Jeff King
2015-01-13  0:11       ` Junio C Hamano
2015-01-13  1:54         ` Jeff King
2015-01-13  1:57           ` [PATCH 1/5] git-compat-util: add xstrdup_or_null helper Jeff King
2015-01-13  2:21             ` Jonathan Nieder
2015-01-13  2:23               ` Jeff King
2015-01-13  1:58           ` [PATCH 2/5] builtin/apply.c: use xstrdup_or_null instead of null_strdup Jeff King
2015-01-13  1:58           ` [PATCH 3/5] builtin/commit.c: use xstrdup_or_null instead of envdup Jeff King
2015-01-13  1:59           ` [PATCH 4/5] use xstrdup_or_null to replace ternary conditionals Jeff King
2015-01-13  1:59           ` [PATCH 5/5] blame.c: fix garbled error message Jeff King
2015-01-14 14:21           ` [PATCH] " Lukas Fleischer
2015-01-14 17:22             ` Junio C Hamano
2015-01-14 20:49               ` Jeff King
2015-01-14 21:54                 ` Junio C Hamano
2015-01-12 23:18     ` Lukas Fleischer [this message]

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