bzr log -r <merged-revision> on a remote branch fails with AttributeError

[Francis J. Lacoste]

It seems that trying to access a revision that was part of a merged fails on a remote branch (bzr+ssh:).

For example, when I run:
$ bzr log -r 5088.2.4 bzr+ssh://devpad.canonical.com/code/leonardr/launchpad/xml-rpc-get-44871bzr: ERROR: exceptions.AttributeError: 'RemoteBranch' object has no attribute '_revision_id_to_revno_cache'

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 802, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 758, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 768, in ignore_pipe
    result = func(*args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 1702, in run
    rev1 = rev2 = revision[0].in_history(b)
  File "/usr/lib/python2.5/site-packages/bzrlib/revisionspec.py", line 225, in in_history
    return self._match_on_and_check(branch, revs)
  File "/usr/lib/python2.5/site-packages/bzrlib/revisionspec.py", line 207, in _match_on_and_check
    info = self._match_on(branch, revs)
  File "/usr/lib/python2.5/site-packages/bzrlib/revisionspec.py", line 325, in _match_on
    revision_id_to_revno = branch.get_revision_id_to_revno_map()
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 127, in read_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 192, in get_revision_id_to_revno_map
    if self._revision_id_to_revno_cache is not None:
AttributeError: 'RemoteBranch' object has no attribute '_revision_id_to_revno_cache'

bzr 0.92.0.candidate.1 on python 2.5.1.final.0 (linux2)
arguments: ['/usr/bin/bzr', 'log', '-r', '5088.2.4', 'bzr+ssh://devpad.canonical.com/code/leonardr/launchpad/xml-rpc-get-44871']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'fr_CA.UTF-8'
plugins:
  bzrtools /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [0.92.0]
  launchpad /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
  multiparent /usr/lib/python2.5/site-packages/bzrlib/plugins/multiparent.pyc [unknown]
  pqm /usr/lib/python2.5/site-packages/bzrlib/plugins/pqm [unknown]

** Please send this report to <email address hidden>
   with a description of what you were doing when the
   error occurred.

[John A Meinel (jameinel)]

The fix is pretty trivial:
=== modified file 'bzrlib/remote.py'
--- bzrlib/remote.py 2007-11-04 20:35:32 +0000
+++ bzrlib/remote.py 2007-11-13 20:09:45 +0000
@@ -934,6 +934,7 @@
         # will try to assign to self.tags, which is a property in this subclass.
         # And the parent's __init__ doesn't do much anyway.
         self._revision_history_cache = None
+ self._revision_id_to_revno_cache = None
         self.bzrdir = remote_bzrdir
         if _client is not None:
             self._client = _client

The reason is that RemoteBranch isn't calling the base Branch.__init__() [there is a comment as to why], but it is using the base classes' implementation of get_revision_id_to_revno_map(), which checks for it.

The only other piece necessary is to add a branch_implementations test that get_revision_id_to_revno_map() works correctly. I'll try and put that together.

[John A Meinel (jameinel)]

It turns out that there is a test for this function. The bug is masked, though. Because when we unlock a branch, we set self._revision_id_to_revno_cache = None.

So:

  remote = bzrlib.branch.Branch.open('bzr+ssh://remote/branch')
  remote.lock_read()
  remote.get_revision_id_to_revno_map() # Fail
  remote.unlock()
  remote.lock_read()
  remote.get_revision_id_to_revno_map() # Success

I'll try to update the test to be more sensitive about this condition.