Re: [PATCH v5 1/3] ls-refs: report unborn targets of symrefs

[Jonathan Tan <jonathantanmy@google.com>]

> So a dangling symref, e.g. "refs/remotes/origin/HEAD -> trunk" when
> no "refs/remotes/origin/trunk" exists, is not reported to send_ref()
> in the same way as an unborn "HEAD"?

I've tried it, and yes, for_each_namespaced_ref() will not report it.
Looking at the code, I think it is packed_ref_iterator_advance() which
checks for broken objects and skips over them.

> I would have expected that we'd
> report where it points at, and for that to work, you'd have to use
> not just the vanilla send_ref() as the callback, but something that
> knows how to do "are we expected to send unborn symrefs" logic, like
> send_possibly_unborn_head does.
> 
> That "changed to tolerate ... should work" worries me.
> 
> If "for_each_namespaced_ref(send_ref, &data)" will never call send_ref()
> with NULL (as in (void *)0) oid, then that would be OK,

If it called send_ref() with (void *)0 OID, it would segfault with the
current code, which calls oid_to_hex() on the OID unconditionally.

> but if it
> ends up calling with NULL somehow, it is responsible to ensure that
> data->symrefs is true and flag has REF_ISSYMREF set, or send_ref()
> would misbehave, (see the first part of your message, which I am
> responding to), no?

If it did, then yes.