# [PATCH] diff: don't presume empty file when corresponding object is missing 2 messages from 2010-10-22 to 2010-10-22. Participants: Nicolas Pitre, Uwe Kleine-König. Thread: https://gitlist.dev/t/25514 ## Nicolas Pitre, 2010-10-22 04:02 Subject: [PATCH] diff: don't presume empty file when corresponding object is missing Message-ID: URL: https://gitlist.dev/e/alpine.LFD.2.00.1010212353550.2764%40xanadu.home ``` The low-level diff code will happily produce totally bogus diff output with a broken repository via format-patch and friends by treating missing objects as empty files. Let's prevent that from happening any longer. Reported-by: Uwe Kleine-König Signed-off-by: Nicolas Pitre --- diff --git a/diff.c b/diff.c index 4732b32..b2839f9 100644 --- a/diff.c +++ b/diff.c @@ -2386,10 +2386,14 @@ int diff_populate_filespec(struct diff_filespec *s, int size_only) } else { enum object_type type; - if (size_only) + if (size_only) { type = sha1_object_info(s->sha1, &s->size); - else { + if (type < 0) + die("unable to read %s", sha1_to_hex(s->sha1)); + } else { s->data = read_sha1_file(s->sha1, &type, &s->size); + if (!s->data) + die("unable to read %s", sha1_to_hex(s->sha1)); s->should_free = 1; } } ``` ## Uwe Kleine-König, 2010-10-22 07:04 Subject: Re: [PATCH] diff: don't presume empty file when corresponding object is missing Message-ID: <20101022070446.GA19834@pengutronix.de> URL: https://gitlist.dev/e/20101022070446.GA19834%40pengutronix.de In-Reply-To: ``` Hi Nicolas, On Fri, Oct 22, 2010 at 12:02:27AM -0400, Nicolas Pitre wrote: > The low-level diff code will happily produce totally bogus diff output > with a broken repository via format-patch and friends by treating missing > objects as empty files. Let's prevent that from happening any longer. > > Reported-by: Uwe Kleine-König Great, this fixes format-patch to fail in my tree as advertised. Tested-by: Uwe Kleine-König > Signed-off-by: Nicolas Pitre Thanks Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | ```