From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 15 Dec 2008 08:36:56 +0000 (-0800)
Subject: git-show: do not segfault when showing a bad tag
X-Git-Tag: v1.6.0.6~9
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=d2dadfe890b5da6f65fe061a414b6ec67c5efe9c;p=git.git

git-show: do not segfault when showing a bad tag

When a tag points at a bad or nonexistent object, we should diagnose the
breakage and exit.  An earlier commit 4f3dcc2 (Fix 'git show' on signed
tag of signed tag of commit, 2008-07-01) lost this check and made it
segfault instead; not good.

This fixes it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/builtin-log.c b/builtin-log.c
index 2efe59373..db71e0da7 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -356,7 +356,13 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 					t->tag,
 					diff_get_color_opt(&rev.diffopt, DIFF_RESET));
 			ret = show_object(o->sha1, 1, &rev);
-			objects[i].item = parse_object(t->tagged->sha1);
+			if (ret)
+				break;
+			o = parse_object(t->tagged->sha1);
+			if (!o)
+				ret = error("Could not read object %s",
+					    sha1_to_hex(t->tagged->sha1));
+			objects[i].item = o;
 			i--;
 			break;
 		}
diff --git a/t/t7007-show.sh b/t/t7007-show.sh
new file mode 100755
index 000000000..cce222f05
--- /dev/null
+++ b/t/t7007-show.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+
+test_description='git show'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	echo hello world >foo &&
+	H=$(git hash-object -w foo) &&
+	git tag -a foo-tag -m "Tags $H" $H &&
+	HH=$(expr "$H" : "\(..\)") &&
+	H38=$(expr "$H" : "..\(.*\)") &&
+	rm -f .git/objects/$HH/$H38
+'
+
+test_expect_success 'showing a tag that point at a missing object' '
+	test_must_fail git --no-pager show foo-tag
+'
+
+test_done