Re: [PATCH 2/2] push -s: skeleton

[Jeff King <peff@peff.net>]

On Thu, Sep 08, 2011 at 03:07:25PM -0700, Shawn O. Pearce wrote:

> A notes tree per ref is ugly when you have a lot of branches. Its a
> problem when you merge commits from say "maint" over to "master" 2
> days after they were initially pushed. Ideally the notes tree for
> master also includes what you brought over.

I agree you can end up with a lot of refs if you have a lot of branches,
and that may get a bit unwieldy.  I don't see how the merge thing is a
problem, though. If you do the merge at a client, then those commits
will hit master by push, and you'll get entries in the cert tree for
master. If you do the merge locally, then there's not going to be a
signature on those commits hitting the master ref, no matter what the
storage scheme.

> However, maybe it is reasonable for a protocol extension to support
> "auto-notes-merge" on a refs/notes/ ref if the client asks for it in
> the send-pack/receive-pack command stream? Clients could push notes
> and have the server automatically merge the client's pushed commit
> into the notes tree, either by fast-forward or by performing an
> automatic notes merge, with concat being applied to non-identical
> notes on the same SHA-1. This would allow the client to prepare his
> local certificate, and push that notes tree, while still working
> around the race on the server side.
> 
> If the server doesn't support the protocol extension, the client can
> still push his signed notes, he just may run into a race with another
> concurrent user pushing into the same repository. Which then means
> that an upgrade of the server is really only important/necessary if
> you have "central repository" model that a lot of users push into. If
> you use the traditional workflow that GitHub encourages of per-user
> repositories, you would never have a race on the server, and wouldn't
> need the upgraded server binary with "auto-notes-merge".

I like this approach, as the protocol extension provides the minimal
building block that can be used to implement this, or any other
notes-related scheme.

-Peff