unpack-trees: don't leak memory in verify_clean_subdirectory()

Fix two different but related memory leaks in
verify_clean_subdirectory(). We leaked both the "pathbuf" if
read_directory() returned non-zero, and we never cleaned up our own
"struct dir_struct" either.

 * "pathbuf": When the read_directory() call followed by the
   free(pathbuf) was added in c81935348be (Fix switching to a branch
   with D/F when current branch has file D., 2007-03-15) we didn't
   bother to free() before we called die().

   But when this code was later libified in 203a2fe1170 (Allow callers
   of unpack_trees() to handle failure, 2008-02-07) we started to leak
   as we returned data to the caller. This fixes that memory leak,
   which can be observed under SANITIZE=leak with e.g. the
   "t1001-read-tree-m-2way.sh" test.

 * "struct dir_struct": We've leaked the dir_struct ever since this
   code was added back in c81935348be.

   When that commit was written there wasn't an equivalent of
   dir_clear(). Since it was added in 270be816049 (dir.c: provide
   clear_directory() for reclaiming dir_struct memory, 2013-01-06)
   we've omitted freeing the memory allocated here.

   This memory leak could also be observed under SANITIZE=leak and the
   "t1001-read-tree-m-2way.sh" test.

This makes all the test in "t1001-read-tree-m-2way.sh" pass under
"GIT_TEST_PASSING_SANITIZE_LEAK=true", we'd previously die in tests
25, 26 & 28.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/unpack-trees.c b/unpack-trees.c
index 8ea0a54..c8d590f 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -2136,9 +2136,10 @@ static int verify_clean_subdirectory(const struct cache_entry *ce,
 	if (o->dir)
 		d.exclude_per_dir = o->dir->exclude_per_dir;
 	i = read_directory(&d, o->src_index, pathbuf, namelen+1, NULL);
+	dir_clear(&d);
+	free(pathbuf);
 	if (i)
 		return add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
-	free(pathbuf);
 	return cnt;
 }