From 6c41e97557d94df7085e3c0cff247305c9401968 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Carlos=20Mart=C3=ADn=20Nieto?= <cmn@elego.de>
Date: Mon, 27 Feb 2012 16:11:53 +0100
Subject: [PATCH] branch: don't assume the merge filter ref exists
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print_ref_list looks up the merge_filter_ref and assumes that a valid
pointer is returned. When the object doesn't exist, it tries to
dereference a NULL pointer. This can be the case when git branch
--merged is given an argument that isn't a valid commit name.

Check whether the lookup returns a NULL pointer and die with an error
if it does. Add a test, while we're at it.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/branch.c  | 4 ++++
 t/t3200-branch.sh | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/builtin/branch.c b/builtin/branch.c
index df908ed8f..d6691af0a 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -528,6 +528,10 @@ static int print_ref_list(int kinds, int detached, int verbose, int abbrev, stru
 	if (merge_filter != NO_FILTER) {
 		struct commit *filter;
 		filter = lookup_commit_reference_gently(merge_filter_ref, 0);
+		if (!filter)
+			die("object '%s' does not point to a commit",
+			    sha1_to_hex(merge_filter_ref));
+
 		filter->object.flags |= UNINTERESTING;
 		add_pending_object(&ref_list.revs,
 				   (struct object *) filter, "");
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 76903323a..6ad1763fd 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -620,4 +620,8 @@ test_expect_success 'use set-upstream on the current branch' '
 
 '
 
+test_expect_success '--merged catches invalid object names' '
+	test_must_fail git branch --merged 0000000000000000000000000000000000000000
+'
+
 test_done
-- 
2.26.2