Re: [PATCH] builtin/gc.c: fix use-after-free in maintenance_unregister()

[Taylor Blau <me@ttaylorr.com>]

On Wed, Nov 16, 2022 at 04:14:30PM +0100, Ævar Arnfjörð Bjarmason wrote:
> >> Copying from other zero-initializations of `struct config_set`:
> >>
> >>     $ git grep -oh 'struct config_set.*= {.*' | sort | uniq -c
> >>           3 struct config_set cs = { { 0 } };
> >
> > Yes, without the double braces the compiler will complain on
> > macOS, I believe.
>
> Ah, that was sorted in 54795d37d9e (config.mak.dev: disable suggest
> braces error on old clang versions, 2022-10-10).
>
> It's fine here, we can follow-up for the #leftoverbits of changing those
> some other time.

Thanks for the reference to 54795d37d9e, Ævar.

There are a small handful of these sitting around in our codebase:

    $ git grep '{ { '
    builtin/gc.c:   struct config_set cs = { { 0 } };
    builtin/worktree.c:             struct config_set cs = { { 0 } };
    oidmap.h:#define OIDMAP_INIT { { NULL } }
    oidset.h:#define OIDSET_INIT { { 0 } }
    reftable/stack_test.c:  struct reftable_ref_record refs[2] = { { NULL } };
    reftable/stack_test.c:  struct reftable_log_record logs[2] = { { NULL } };
    reftable/stack_test.c:  struct reftable_ref_record refs[2] = { { NULL } };
    reftable/stack_test.c:  struct reftable_log_record logs[2] = { { NULL } };
    reftable/stack_test.c:  struct reftable_log_record logs[20] = { { NULL } };
    reset.c:        struct tree_desc desc[2] = { { NULL }, { NULL } };
    t/helper/test-ref-store.c:static struct flag_definition empty_flags[] = { { NULL, 0 } };
    worktree.c:     struct config_set cs = { { 0 } };

But I tend to agree that I'm not all that eager to go and change these
for the sake of changing them. I think we can slowly let them age out of
the codebase when we're touching nearby areas in the future.

Thanks,
Taylor