From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 12 Jun 2019 17:26:01 GMT
Subject: Re: push.recurseSubmodules=check doesn't consider tags
Message-ID: <xmqqef3yk95i.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <62F6F2E3-FAED-4EE9-BDB8-D484252A845F@arilinc.com>

Scott Johnson <scott.johnson@arilinc.com> writes:

> I occasionally rebase my submodules. I realize the danger (historical submodule pointers could point to commits that get garbage-collected away) so I always create and push a tag before the rebase, to make sure the old commits will never get purged. I believe this is safe, based on some experiments I’ve run.
>
> The issue: I set the config var push.recurseSubmodules=check, and
> it seems to insist on having a branch and not merely a tag.

I suspect that this is pretty much by design.

When deciding if it needs a push in a submodule repository,
submodule.c::submodule_needs_pushing() gets called and asked to
check what is available at the remote without actually making a
connection to the other side.  It is done by looking at the
remote-tracking branches in the copy of the submodule repository we
have locally.  As there is no "remote-tracking tags" (iow, you
cannot tell from the output of "git -C submodule tag -l" if each of
the tags you have locally in your copy of the submodule exists in
another repository you push to and fetch from), this process does
not look at refs/tags/ hierarchy of your copy of the submodule
repository and that is quite deliberate, I would think.