Bazaar tells me my source branch format doesn't support stacking, even though it does.

[Jonathan Lange]

On initial push, using bzr.dev r4041

$ ~/src/bzr/bzr.dev/bzr -Dhpss push
Using saved push location: bzr+ssh://bazaar.launchpad.net/~jml/launchpad/source-package-branch-listing
Using default stacking branch /~launchpad-pqm/launchpad/devel at bzr+ssh://bazaar.launchpad.net/%7Ejml/launchpad/
Source format does not support stacking, using format: '1.6'
  Packs 5 (adds stacking support, requires bzr 1.6)

Created new stacked branch referring to /~launchpad-pqm/launchpad/devel.
HPSS calls: 140 <bzrlib.smart.medium.SmartSSHClientMedium object at 0x254a050>

But the format of the branch is Branch Format 7:
$ bzr info ~/repos/launchpad/source-package-branch-listing/
Repository branch (format: 1.6)
Location:
  shared repository: /home/jml/repos/launchpad
  repository branch: /home/jml/repos/launchpad/source-package-branch-listing

Related branches:
  public branch: bzr+ssh://bazaar.launchpad.net/~jml/launchpad/source-package-branch-listing
    push branch: bzr+ssh://bazaar.launchpad.net/~jml/launchpad/source-package-branch-listing
  parent branch: /home/jml/repos/launchpad/trunk
  submit branch: /home/jml/repos/launchpad/trunk

Format:
       control: Meta directory format 1
        branch: Branch format 7
    repository: Packs 5 (adds stacking support, requires bzr 1.6)

Branch history:
      7847 revisions
^C

[Andrew Bennetts (spiv)]

Fixed in bzr.dev, hopefully will be cherrypicked for 1.13.