Re: [PATCH v3 2/6] notes: replace pseudorefs with real refs

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 29, 2015, 02:00 UTC
Message-ID: <xmqqh9onbu53.fsf@gitster.dls.corp.google.com>
In-Reply-To: <55B824BD.8000003@alum.mit.edu>

Michael Haggerty <mhagger@alum.mit.edu> writes:

Show 11 quoted lines

> It sounds like what a notes merge really wants is a new linked worktree
> that has branch refs/notes/foo checked out:
>
> * This would allow multiple notes merges to take place at the same time
> provided they target different merge references.
>
> * This would prevent multiple notes merges to the same notes reference
> at the same time by the same mechanism that prevents the same branch
> from being checked out in two linked worktrees at the same time.
>
> It's just a thought; I have no idea whether it is practical...

That was certainly one of the possibilities that crossed my mind.

In any case, the primary thing I am interested in at this point is to unblock David's "prepare things so that we can put primary refs in a different ref backends more easily" topic, and I've already made my point a few messages ago upstream:

    I think it is OK for us to admit that the "notes" subsystem is
    not quite ready to work well with multiple working tree world
    yet [*1*], and move this series forward without worrying about
    them.

So doing the absolute minimum, leaving the "now what can we do to improve notes-merge process?" outside the scope of the topic.

Improving the notes-merge process is also an interesting topic, but it is clear that people started thinking about it today ;-), so it can wait without blocking David's work. The refs/notes/* hierarchy will be handled exactly the same way as regular branches in the pluggable ref-backends, and how the ephemeral REF_NOTES_REF and friends are represented (some are refs, some may be pseudo-refs, some may be just a filesystem entity) would need to be revamped if we really do the "improving notes-merge" thing anyway, so David's topic shouldn't be blocked by the "possible future tweak" of the current design that hasn't happened yet. Instead, improving notes-merge can be done on top, potentially undoing and redoing Davi'd topic.