From: Nicolas Pitre <nico@fluxnic.net>
Date: Fri, 22 Oct 2010 04:02:27 +0000 (-0400)
Subject: diff: don't presume empty file when corresponding object is missing
X-Git-Tag: v1.7.3.4~24^2
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=c50c4316e1eed362bee387e4cbfbe1138957f75b;p=git.git

diff: don't presume empty file when corresponding object is missing

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 <u.kleine-koenig@pengutronix.de>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/diff.c b/diff.c
index 381cc8d4f..69cdae54b 100644
--- a/diff.c
+++ b/diff.c
@@ -2124,10 +2124,14 @@ 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;
 		}
 	}