From 14763e7bda06a502455ef4420067205797b9a907 Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson@yhbt.net>
Date: Wed, 11 Oct 2006 16:16:02 -0700
Subject: [PATCH] commit: fix a segfault when displaying a commit with
 unreachable parents

I was running git show on various commits found by fsck-objects
when I found this bug.  Since find_unique_abbrev() cannot find
an abbreviation for an object not in the database, it will
return NULL, which is bad to run strlen() on.  So instead, we'll
just display the unabbreviated sha1 that we referenced in the
commit.

I'm not sure that this is the best 'fix' for it because the
commit I was trying to show was broken, but I don't think a
program should segfault even if the user tries to do something
stupid.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
---
 commit.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/commit.c b/commit.c
index 5b6e082c85..a6d543eee7 100644
--- a/commit.c
+++ b/commit.c
@@ -548,10 +548,13 @@ static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *com
 
 	while (parent) {
 		struct commit *p = parent->item;
-		const char *hex = abbrev
-			? find_unique_abbrev(p->object.sha1, abbrev)
-			: sha1_to_hex(p->object.sha1);
-		const char *dots = (abbrev && strlen(hex) != 40) ? "..." : "";
+		const char *hex = NULL;
+		const char *dots;
+		if (abbrev)
+			hex = find_unique_abbrev(p->object.sha1, abbrev);
+		if (!hex)
+			hex = sha1_to_hex(p->object.sha1);
+		dots = (abbrev && strlen(hex) != 40) ?  "..." : "";
 		parent = parent->next;
 
 		offset += sprintf(buf + offset, " %s%s", hex, dots);
-- 
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