[MERGE][bug 115343] Allow 'bzr branch -r revid:xxx' to branch any revision in ancestry

[Andrew Bennetts]

Aaron Bentley wrote:
> John Arbash Meinel wrote:
> > The attached patch makes "BzrBranch6" also support it. I only test that
> > you can branch anything in Ancestry (not just in your repository) since
> > that seemed more realistic for foreign branches. (And if we ever
> > implement any sort of auto-gc).
> 
> I think I would prefer to ensure you can branch from anything in your
> repository, not just in your ancestry.  This allows you to restore
> branches that you may have deleted by accident.

I think this is a useful feature to have too.  We should have a test for it...

Although, it is a bit nasty that branches are expected to allow you to address
revisions they don't have in their ancestry (but happen to exist in the same
repository).  What if we had a revisionspec or other syntax for explicitly
addressing a revision ID in a repository?  e.g.:

    bzr branch -r revid:id1234 --use-repository=path/to/repo

Maybe that's being overly fussy, but I think maybe we'll confuse people about
our model less if we keep the distinction between branches and repositories
clear.

-Andrew.