path: root/help.c
diff options
authorJeff King <>2019-05-14 12:04:31 (GMT)
committerJunio C Hamano <>2019-05-15 01:58:00 (GMT)
commit8ed51b066681adc88723dbe07b878904c348fdf6 (patch)
tree91c8dee440a584b00827ae2a2bdd0d72635e2e45 /help.c
parentaeb582a98374c094361cba1bd756dc6307432c42 (diff)
help_unknown_ref(): duplicate collected refnames
When "git merge" sees an unknown refname, we iterate through the refs to try to suggest some possible alternates. We do so with for_each_ref(), and in the callback we add some of the refnames we get to a string_list that is declared with NODUP, directly adding a pointer into the refname string our callback received. But the for_each_ref() machinery does not promise that the refname string will remain valid, and as a result we may print garbage memory. The code in question dates back to its inception in e56181060e (help: add help_unknown_ref(), 2013-05-04). But back then, the refname strings generally did remain stable, at least immediately after the for_each_ref() call. Later, in d1cf15516f (packed_ref_iterator_begin(): iterate using `mmapped_ref_iterator`, 2017-09-25), we started consistently re-using a separate buffer for packed refs. The fix is simple: duplicate the strings we intend to collect. We already call string_list_clear(), so the memory is correctly freed. Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'help.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/help.c b/help.c
index 520c908..5583f6c 100644
--- a/help.c
+++ b/help.c
@@ -773,7 +773,7 @@ static int append_similar_ref(const char *refname, const struct object_id *oid,
static struct string_list guess_refs(const char *ref)
struct similar_ref_cb ref_cb;
- struct string_list similar_refs = STRING_LIST_INIT_NODUP;
+ struct string_list similar_refs = STRING_LIST_INIT_DUP;
ref_cb.base_ref = ref;
ref_cb.similar_refs = &similar_refs;