Re: [StGIT RFC] Changing patch@branch syntax

From: Karl Hasselström <kha@treskal.com>
Date: May 16, 2007, 06:54 UTC
Message-ID: <20070516065438.GA7453@diana.vm.bytemark.co.uk>
In-Reply-To: <20070515220310.GJ16903@nan92-1-81-57-214-146.fbx.proxad.net>

On 2007-05-16 00:03:10 +0200, Yann Dirson wrote:

> The patch@branch syntax is annoying, at least for bash-completion
> purposes: we don't want to provide all possible completions accross
> all branches, yet we'd like to get completion for foreign patches.

Yes, that's annoying.

> Another place where I feel it is bad is when using the full
> "patch@branch//top" syntax: the MSB is in the middle, and the LSB is
> on the right.

I agree. (Similarly, YYYYMMDD is the one true date format!)

Show 8 quoted lines

> Both issues would be solved by switching to a MSB ordering, with a
> way to distinguish branchnames when given. Something similar to
> pathnames would fit well - eg. [/branchname/]patchname[//top].
> However, I'm not sure using slashes would be a good choice,
> precisely because of the similarity with real pathnames. But we
> don't have so many separator chars that are not special in one way
> or another, and would require quoting them to avoid more user
> confusion.

Branch names can contain slashes, and in the future patch names might as well, so we'd need another separator. _Except_ for the fact that if foo/bar is a branch, foo/bar/baz can't also be a branch, so using a slash as separator is actually unambiguous.

If we similarly make it illegal for patches a/b and a/b/c to exist simultaneously (whenever we get around to implementing slashy patch names), we could use a single slash for patchname/{top,bottom} too.

The only remaining difficulty is to decide whether a/b/c is patch b/c on branch a, or patch a/b/c on the current branch. We can't forbid patch names and branch names to collide, since git can create new branch names behind stgit's back. So I guess we'd need some way to indicate whether branch name is included. The leading slash in your suggestion seems as good a way as any.

However, I'm not going to recommend using only slashes. I believe life will be much simpler if we simply use two different separators, like this:

  branch:patch@top

Then all these subsets will be trivially parseable:

  branch:patch

  patch

  patch@top

And even this one, if we feel crazy some day:

  /path/to/other/repository#branch:patch@top

-- 
Karl Hasselström, kha@treskal.com
      www.treskal.com/kalle