[PATCH v2] commit: check result of resolve_ref_unsafe

From: Andrey Okoshkin <a.okoshkin@samsung.com>
Date: Oct 19, 2017, 09:36 UTC
Message-ID: <5fa1f5c6-249e-2aa9-5e9f-c00ebe2c0d9d@samsung.com>
In-Reply-To: <0e396c24-167f-901e-9122-cdc17164ec1e@samsung.com>

Add check of the resolved HEAD reference while printing of a commit summary. resolve_ref_unsafe() may return NULL pointer if underlying calls of lstat() or open() fail in files_read_raw_ref(). Such situation can be caused by race: file becomes inaccessible to this moment.

Signed-off-by: Andrey Okoshkin <a.okoshkin@samsung.com>
---
Thank you for your review.

Changes since the previous patch:
* BUG is replaced with die, message;
* Message is changed.

  builtin/commit.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/builtin/commit.c b/builtin/commit.c
index 1a0da71a4..cc27c9af7 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1483,6 +1483,8 @@ static void print_summary(const char *prefix, 
const struct object_id *oid,
  	diff_setup_done(&rev.diffopt);

  	head = resolve_ref_unsafe("HEAD", 0, junk_oid.hash, NULL);
+	if (!head)
+		die(_("unable to resolve HEAD after creating commit"));
  	if (!strcmp(head, "HEAD"))
  		head = _("detached HEAD");
  	else

-- 
2.14.2