[MERGE] Add BzrDir.get_branch_stacked_on_url

[Jonathan Lange]

On Tue, Sep 2, 2008 at 10:21 AM, Aaron Bentley <aaron at aaronbentley.com> wrote:
> Jonathan Lange wrote:
>> On Tue, Sep 2, 2008 at 9:58 AM, Aaron Bentley <aaron at aaronbentley.com> wrote:
>>> Aaron Bentley has voted comment.
>>> Status is now: Waiting
>>> Comment:
>>> Why?  Does Branch.open hit the stacked_on_url?
>>>
>>
>> Yes, it does.
>
> Well, I'm not opposed to this as a stop-gap as long as you file a bug
> that we shouldn't open fallback branches until we know that we need them.
>

I've filed https://bugs.edge.launchpad.net/bzr/+bug/263807.

> The patch as it stands assumes too much about the way branches are
> configured.  This would fail spectacularly with a Subversion branch, if
> they supported stacking.
>

Fair enough.

> There should be indirection through the branch format to ensure that
> branch formats can determine how their configuration is acquired and how
> stacking in particular is configured.  That code should be reused by
> BzrBranch6 in the implementation of get_stacked_on_url.
>

So, something like Format.get_stacked_on_url(bzrdir)?

Also, did you mean to say BzrBranch7? If not, why pick out BzrBranch6?

jml