Re: cg-clone, tag objects and cg-push/git-push don't play nice

[Junio C Hamano <junkio@cox.net>]

Martin Langhoff <martin.langhoff@gmail.com> writes:

>> That is expected.
>
> Hmmm. I was under the impression that if I call git-push naming a
> particular head, it could restrict itself to the stuff needed for that
> head only. Just to clarify, I'm running
>
>   git-push locke.catalyst.net.nz:/var/git/moodle-test.git master:mdl-topnz-prod

Yeah.  But the problem is that the repository on the other end
claims that it has everything reachable from those incomplete
tags.  Hearing that, git-push (the real name of it is send-pack)
decides not to send things that are already reachable from the
refs the other end claims to have.  So if an incomplete tag
refers to a commit that contains a blob that the remote actually
does not have, and if that blob is part of the head you are
pushing, send-pack would not (and should not) send that blob to
the remote.

>> I do not understand why removing .git/refs/tags/* did not help,
>> and that is the biggest thing that disturbs me in this whole
>> problem report
>
> I can't understand that either, but I manually removed all the
> refs/tags, and the only heads I have are origin and master. git-push
> won't let me do it until the exact point where I have removed the
> object from the repo. And that's only possible on unpacked repos.

Hmph.  It worries me even more.

This error message:

      error: unpack should have generated
    482d4b88aa482dfea7f7549470902049a050020a, but I can't find it!

comes from receive-pack that runs on the other repo (i.e. the
one with incomplete tags you just removed), so it means
send-pack decided it does not need to send that object --
meaning the other end claimed it already has it.  What to send
and what need not to be sent is determined solely based on what
send-pack hears from receive-pack in the initial handshake,
which is in receive-pack.c::write_head_info().  It scans
everything under ".git/refs" directory (not just .git/refs/heads
or .git/refs/tags; if you had ".git/refs/FOOBAR", it will cause
the remote end to claim it has everything reachable from it --
the only exceptions are things that starts with a dot '.', which
is probably why cg-fetch places a temporary heads in
refs/*/.$name-fetching) and sends them -- it does not look at
the object directory and magically claim it has something that
is not recorded in its .git/refs/ directory.