[PATCH v2 3/6] grep: fix a "path_list" memory leak

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Free the "path_list" used in builtin/grep.c, it was declared as
STRING_LIST_INIT_NODUP, let's change it to a STRING_LIST_INIT_DUP
since an early user in cmd_grep() appends a string passed via
parse-options.c to it, which needs to be duplicated.

Let's then convert the remaining callers to use
string_list_append_nodup() instead, allowing us to free the list.

This makes all the tests in t7811-grep-open.sh pass, 6/10 would fail
before this change. The only remaining failure would have been due to
a stray "git checkout" (which still leaks memory). In this case we can
use a "git reset --hard" instead, so let's do that, and move the
test_when_finished() above the code that would modify the relevant
file.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/grep.c       | 9 +++++----
 t/t7811-grep-open.sh | 3 ++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/builtin/grep.c b/builtin/grep.c
index 555b2ab6008..9e34a820ad4 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -401,7 +401,7 @@ static void append_path(struct grep_opt *opt, const void *data, size_t len)
 
 	if (len == 1 && *(const char *)data == '\0')
 		return;
-	string_list_append(path_list, xstrndup(data, len));
+	string_list_append_nodup(path_list, xstrndup(data, len));
 }
 
 static void run_pager(struct grep_opt *opt, const char *prefix)
@@ -839,7 +839,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	struct grep_opt opt;
 	struct object_array list = OBJECT_ARRAY_INIT;
 	struct pathspec pathspec;
-	struct string_list path_list = STRING_LIST_INIT_NODUP;
+	struct string_list path_list = STRING_LIST_INIT_DUP;
 	int i;
 	int dummy;
 	int use_index = 1;
@@ -1159,8 +1159,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			strbuf_addf(&buf, "+/%s%s",
 					strcmp("less", pager) ? "" : "*",
 					opt.pattern_list->pattern);
-			string_list_append(&path_list,
-					   strbuf_detach(&buf, NULL));
+			string_list_append_nodup(&path_list,
+						 strbuf_detach(&buf, NULL));
 		}
 	}
 
@@ -1195,6 +1195,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	if (hit && show_in_pager)
 		run_pager(&opt, prefix);
 	clear_pathspec(&pathspec);
+	string_list_clear(&path_list, 0);
 	free_grep_patterns(&opt);
 	object_array_clear(&list);
 	free_repos();
diff --git a/t/t7811-grep-open.sh b/t/t7811-grep-open.sh
index a98785da795..1dd07141a7d 100755
--- a/t/t7811-grep-open.sh
+++ b/t/t7811-grep-open.sh
@@ -3,6 +3,7 @@
 test_description='git grep --open-files-in-pager
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pager.sh
 unset PAGER GIT_PAGER
@@ -114,8 +115,8 @@ test_expect_success 'modified file' '
 	unrelated
 	EOF
 
+	test_when_finished "git reset --hard" &&
 	echo "enum grep_pat_token" >unrelated &&
-	test_when_finished "git checkout HEAD unrelated" &&
 	GIT_PAGER=./less git grep -F -O "enum grep_pat_token" >out &&
 	test_cmp expect actual &&
 	test_must_be_empty out
-- 
2.33.1.1494.g88b39a443e1