[MERGE] Add Branch support to CommitBuilder

[Martin Pool]

On 16 Jan 2007, Jelmer Vernooij <jelmer at samba.org> wrote:
> The attached patch lets CommitBuilder take care of updating the branch
> revision history. It updates the master branch and optionally the local
> branch, if specified.
> 
> This fixes https://bugs.launchpad.net/ubuntu/+source/bzr/+bug/79330
> 
> No backwards compatibility for older versions of CommitBuilder is
> provided. Is that ok, given the number of custom CommitBuilders
> (bzr-svn's is the only I'm aware of), or should there be backwards
> compatibility?

I think that is ok, though it deserves a mention in the 'internals'
section of the news file.

It seems a bit unfortunate that this needs to touch so many places in
repository.py, but i suppose that's because get_commit_builder is
overridden just to check the parameters.  We could clean that up by
having downcalls to set these policies.  Also it seems that the
repository rarely cares about the parameters - it could just return the
commit builder class? - which would reduce the appearance of long
argument dicts being passed around.

+0.9 from me, just because it adds more redundancy.

-- 
Martin