cocci: generalize "unused" rule to cover more than "strbuf"

Generalize the newly added "unused.cocci" rule to find more than just
"struct strbuf", let's have it find the same unused patterns for
"struct string_list", as well as other code that uses
similar-looking *_{release,clear,free}() and {release,clear,free}_*()
functions.

We're intentionally loose in accepting e.g. a "strbuf_init(&sb)"
followed by a "string_list_clear(&sb, 0)".  It's assumed that the
compiler will catch any such invalid code, i.e. that our
constructors/destructors don't take a "void *".

See [1] for example of code that would be covered by the
"get_worktrees()" part of this rule. We'd still need work that the
series is based on (we were passing "worktrees" to a function), but
could now do the change in [1] automatically.

1. https://lore.kernel.org/git/Yq6eJFUPPTv%2Fzc0o@coredump.intra.peff.net/

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

1 files changed, 0 insertions, 2 deletions

diff --git a/builtin/repack.c b/builtin/repack.c
index 4a7ae4cf48..482b66f57d 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -727,7 +727,6 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	struct string_list_item *item;
 	struct string_list names = STRING_LIST_INIT_DUP;
-	struct string_list rollback = STRING_LIST_INIT_NODUP;
 	struct string_list existing_nonkept_packs = STRING_LIST_INIT_DUP;
 	struct string_list existing_kept_packs = STRING_LIST_INIT_DUP;
 	struct pack_geometry *geometry = NULL;
@@ -1117,7 +1116,6 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	}
 
 	string_list_clear(&names, 0);
-	string_list_clear(&rollback, 0);
 	string_list_clear(&existing_nonkept_packs, 0);
 	string_list_clear(&existing_kept_packs, 0);
 	clear_pack_geometry(geometry);