[PATCH 3/7] list-objects.c: handle unexpected non-blob entries

From: Taylor Blau <me@ttaylorr.com>
To: git@vger.kernel.org
Cc: peff@peff.net, gitster@pobox.com
Subject: [PATCH 3/7] list-objects.c: handle unexpected non-blob entries
Date: Thu, 4 Apr 2019 20:37:46 -0700	[thread overview]
Message-ID: <75f20ee26def257aa45dd31cd016ee76f81dcb83.1554435033.git.me@ttaylorr.com> (raw)
In-Reply-To: <cover.1554435033.git.me@ttaylorr.com>

Fix one of the cases described in the previous commit where a tree-entry
that is promised to a blob is in fact a non-blob.

When 'lookup_blob()' returns NULL, it is because Git has cached the
requested object as a non-blob. In this case, prevent a SIGSEGV by
'die()'-ing immediately before attempting to dereference the result.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 list-objects.c                         | 5 +++++
 t/t6102-rev-list-unexpected-objects.sh | 5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/list-objects.c b/list-objects.c
index dc77361e11..ea04bbdee6 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -133,6 +133,11 @@ static void process_tree_contents(struct traversal_context *ctx,
 					base, entry.path);
 		else {
 			struct blob *b = lookup_blob(ctx->revs->repo, &entry.oid);
+			if (!b) {
+				die(_("entry '%s' in tree %s has blob mode, "
+				      "but is not a blob"),
+				    entry.path, oid_to_hex(&tree->object.oid));
+			}
 			b->object.flags |= NOT_USER_GIVEN;
 			process_blob(ctx, b, base, entry.path);
 		}
diff --git a/t/t6102-rev-list-unexpected-objects.sh b/t/t6102-rev-list-unexpected-objects.sh
index 472b08528a..76fe9be30f 100755
--- a/t/t6102-rev-list-unexpected-objects.sh
+++ b/t/t6102-rev-list-unexpected-objects.sh
@@ -19,8 +19,9 @@ test_expect_failure 'traverse unexpected non-blob entry (lone)' '
 	test_must_fail git rev-list --objects $broken_tree
 '
 
-test_expect_failure 'traverse unexpected non-blob entry (seen)' '
-	test_must_fail git rev-list --objects $tree $broken_tree
+test_expect_success 'traverse unexpected non-blob entry (seen)' '
+	test_must_fail git rev-list --objects $tree $broken_tree >output 2>&1 &&
+	test_i18ngrep "is not a blob" output
 '
 
 test_expect_success 'setup unexpected non-tree entry' '
-- 
2.21.0.203.g358da99528

