Re: [RFC] Refspec patterns with * in the middle

From: Daniel Barkalow <barkalow@iabervon.org>
Date: Mar 2, 2009, 18:22 UTC
Message-ID: <alpine.LNX.1.00.0903021231510.19665@iabervon.org>
In-Reply-To: <7viqmrn98i.fsf@gitster.siamese.dyndns.org>

On Mon, 2 Mar 2009, Junio C Hamano wrote:

Show 14 quoted lines

> Daniel Barkalow <barkalow@iabervon.org> writes:
> 
> > My use case is actually, more precisely:
> >
> > some/constant/stuff/$PROJ-$NUMBER/junk/my-proj
> >
> > Where $NUMBER is the version number, and $PROJ is usually, but not quite 
> > always "my-proj"; the exception being that it might be effectively a 
> > superproject. So I'd like to have:
> >
> >  fetch = some/constant/stuff/my-proj-*/junk/my-proj:refs/remotes/origin/*
> 
> ... and expect "some/constant/stuff/my-proj-2.5/junk/my-proj" to be mapped
> to "refs/remotes/origin/2.5"?  I think it does not look too bad.

Yeah.

Show 13 quoted lines

> > But I can live with remote branches like "my-proj-2.4" instead of "2.4".
> >
> > I think it would make sense, and limit typo damage, to say that the * can 
> > only expand to something with a '/' in it if the star has a slash or the 
> > end of the string on each side.
> 
> I do not understand what you mean by "* can only expand to something with
> a '/' in it if ..." part.  None of the examples in your message have a
> case where the asterisk matches across directory boundaries, and I thought
> you would simply say "* does not match /" and be done with that.
> 
> What scenario do you have in mind that wants to match a slash with an
> asterisk?

Backwards compatibility? Currently, refs/heads/*:refs/remotes/origin/* will match refs/heads/js/notes with refs/remotes/origin/js/notes, because it simply copies everything after the fixed prefix.

I was assuming that that particular matching is an existing requirement (and that you used it regularly to share topic-maintenance work between machines).

So my idea was that a path component of "*" would be able to match multiple levels, while a path component of "something-*" or "*-something" can only match a single path component that starts or ends with the right thing. Looking at it now, I think it might be more sane to use "%" for the second case, and say: "*" must be used as a full path component, and matches one or more path components; "%" may be used as part of a path component, and doesn't match the path separator; you can only use one such character, and both sides of the refspec have to agree on which.

I think the problem cases were typos like:

refs/heads*:refs/remotes/origin/* (used to cause problems)

and

refs/heads/*:refs/remotes/origin* (gives you the originmaster remote?)

	-Daniel
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