dpush blew up again; CachingBzrRevisionMetadata mismatch

[Glyph Lefkowitz]

$ bzr dpush http://svn.calendarserver.org/repository/calendarserver/CalendarServer/branches/users/glyph/quota
bzr: ERROR: exceptions.AssertionError: Expected <CachingBzrRevisionMetadata for revision 7629, path CalendarServer/branches/users/glyph/quota in repository 'e27351fd-9f3e-4f54-a53b-843176b1656c'> got <CachingBzrRevisionMetadata for revision 7628, path CalendarServer/branches/users/glyph/quota in repository 'e27351fd-9f3e-4f54-a53b-843176b1656c'>

Traceback (most recent call last):
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 926, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 1126, in run_bzr
    ret = run(*run_argv)
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 691, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/Library/Python/2.6/site-packages/bzrlib/commands.py", line 713, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/Library/Python/2.6/site-packages/bzrlib/foreign.py", line 319, in run
    push_result = source_branch.lossy_push(target_branch)
  File "/Library/Python/2.6/site-packages/bzrlib/branch.py", line 1116, in lossy_push
    return lossy_push(stop_revision)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/branch.py", line 993, in lossy_push
    result.revidmap = self._update_revisions_lossy(stop_revision)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/branch.py", line 970, in _update_revisions_lossy
    push_metadata=False, base_revid=base_revid)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/push.py", line 248, in push
    override_svn_revprops=target_config.get_override_svn_revprops())
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/push.py", line 152, in push_revision_tree
    testament=testament)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/commit.py", line 464, in __init__
    self.base_revno = graph.find_distance_to_null(self.base_revid, [])
  File "/Library/Python/2.6/site-packages/bzrlib/graph.py", line 322, in find_distance_to_null
    parent_map = self.get_parent_map(to_search)
  File "/Library/Python/2.6/site-packages/bzrlib/graph.py", line 99, in get_parent_map
    new_found = parents_provider.get_parent_map(remaining)
  File "/Library/Python/2.6/site-packages/bzrlib/graph.py", line 167, in get_parent_map
    parent_map = self._get_parent_map(needed_revisions)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/parents.py", line 35, in get_parent_map
    newfound = self.actual.get_parent_map(todo)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/repository.py", line 964, in get_parent_map
    parent_map[revision_id] = revmeta.get_parent_ids(mapping)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/revmeta.py", line 926, in get_parent_ids
    parent_ids = self.base.get_parent_ids(mapping)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/revmeta.py", line 621, in get_parent_ids
    lhs_parent = self.get_lhs_parent_revid(mapping)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/revmeta.py", line 450, in get_lhs_parent_revid
    return self.get_implicit_lhs_parent_revid(mapping)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/revmeta.py", line 423, in get_implicit_lhs_parent_revid
    parentrevmeta = self.get_lhs_parent_revmeta(mapping)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/revmeta.py", line 380, in get_lhs_parent_revmeta
    nm = get_next_parent(self)
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/revmeta.py", line 375, in get_next_parent
    pm = nm.get_direct_lhs_parent_revmeta()
  File "/Library/Python/2.6/site-packages/bzrlib/plugins/svn/revmeta.py", line 359, in get_direct_lhs_parent_revmeta
    assert self == firstrevmeta, "Expected %r got %r" % (self, firstrevmeta)
AssertionError: Expected <CachingBzrRevisionMetadata for revision 7629, path CalendarServer/branches/users/glyph/quota in repository 'e27351fd-9f3e-4f54-a53b-843176b1656c'> got <CachingBzrRevisionMetadata for revision 7628, path CalendarServer/branches/users/glyph/quota in repository 'e27351fd-9f3e-4f54-a53b-843176b1656c'>

bzr 2.3.1 on python 2.6.1 (Darwin-10.7.0-i386-64bit)
arguments: ['/usr/local/bin/bzr', 'dpush', 'http://svn.calendarserver.org/repository/calendarserver/CalendarServer/branches/users/glyph/quota']
encoding: 'UTF-8', fsenc: 'utf-8', lang: 'en_US.UTF-8'
plugins:
  bash_completion /Library/Python/2.6/site-packages/bzrlib/plugins/bash_completion [2.3.1]
  bisect /Domicile/glyph/.bazaar/plugins/bisect [1.1.0dev]
  bzrtools /Library/Python/2.6/site-packages/bzrlib/plugins/bzrtools [2.3.1]
  colo /Library/Python/2.6/site-packages/bzrlib/plugins/colo [0.2.1]
  email /Library/Python/2.6/site-packages/bzrlib/plugins/email [unknown]
  explorer /Library/Python/2.6/site-packages/bzrlib/plugins/explorer [1.1.2]
  extmerge /Library/Python/2.6/site-packages/bzrlib/plugins/extmerge [unknown]
  fastimport /Library/Python/2.6/site-packages/bzrlib/plugins/fastimport [0.10.0]
  keychain /Library/Python/2.6/site-packages/bzrlib/plugins/keychain [0.1.0]
  launchpad /Library/Python/2.6/site-packages/bzrlib/plugins/launchpad [2.3.1]
  loom /Library/Python/2.6/site-packages/bzrlib/plugins/loom [2.2.1dev]
  netrc_credential_store /Library/Python/2.6/site-packages/bzrlib/plugins/netrc_credential_store [2.3.1]
  news_merge /Library/Python/2.6/site-packages/bzrlib/plugins/news_merge [2.3.1]
  pipeline /Library/Python/2.6/site-packages/bzrlib/plugins/pipeline [1.1.0]
  push_and_update /Domicile/glyph/.bazaar/plugins/push_and_update [0.2.0dev]
  qbzr /Library/Python/2.6/site-packages/bzrlib/plugins/qbzr [0.20.0]
  rewrite /Library/Python/2.6/site-packages/bzrlib/plugins/rewrite [0.6.2]
  shortcuts /Domicile/glyph/.bazaar/plugins/shortcuts [unknown]
  svn /Library/Python/2.6/site-packages/bzrlib/plugins/svn [1.0.5dev]
  upload /Library/Python/2.6/site-packages/bzrlib/plugins/upload [1.0.1dev]
  xmloutput /Library/Python/2.6/site-packages/bzrlib/plugins/xmloutput [0.8.7.dev]

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
        https://bugs.launchpad.net/bzr/+filebug
    including this traceback and a description of the problem.
[Error: 4]

[Glyph Lefkowitz (glyph)]

Aha! This occurs because my branch has a "null" change in it: no files were changed. You can see my two attempts to dpush this change here: <http://trac.calendarserver.org/changeset/7629> and here: <http://trac.calendarserver.org/changeset/7630>.

bzr-svn then understandably has no way to associate the change with the branch. This is still a bug, but at least the workaround for the future is easy :).