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

From: Junio C Hamano <[email-masked]>
Date: Tue, 28 Jul 2015 15:52:17 -0700

Johan Herland <[email-masked]> writes:

Johan Herland <[email-masked]> writes:

> However, in any case, notes merges are always per _repo_ and never per
> _worktree_, so this is all unrelated to the current patch/discussion
> AFAICS.

Thanks for chiming in, but I actually think you are confused.

"git merge" is always per _repo_ in the sense that the result of a
merge of a topic to the 'master' is recorded in the 'master' which
is per-repo.  In the multi-worktree world order, that does not
change.  What changes is that you could have different worktrees
that check out different branches.  Worktree A may have 'master'
checked out and do the merge there to update the tip of 'master'.
But while worktree A is doing that, worktree B may have 'next'
checked out and do an unrelated merge there.  Once worktree A leaves
'master' by checking out another branch, worktree B is free to check
out 'master' and do further merges there.  Merging into 'master' is
per _repo_, but the act of merging is per worktree.

I think merges of refs/notes/commits and refs/notes/someotherthing
works exactly the same way.  In worktree A, you may decide to merge
a notes tree refs/notes/commits with somebody else's.  It may
conflict and you may need to "lock" refs/notes/commits from being
touched by other worktrees while resolving that, but that does not
mean other worktrees cannot do a merge of refs/notes/someotherthing
at all.  The temporary area you use for merging notes, i.e. the
working tree as far as notes merge is concerned, is private to
worktree A and does not need to be seen by other worktrees.

So while you are working on merging and resolving, that intermediate
state is *NOT* per _repo_ at all.  It is at most per worktree (Yes
you could extend and have one notes_merge_ref per each refs/notes/*
ref to make it even finer grained to allow more than one notes merge
going on inside a single worktree, but I do not think it is worth
it).