Comment 1 for bug 677328

It is reproducible in a simple example (feel free to use this as a test case):

nmb@guttle[~/tmp]$ bzr init test1
rCreated a standalone tree (format: 2a)
nmb@guttle[~/tmp]$ bzr branch test1 test2
Branched 0 revision(s).
nmb@guttle[~/tmp]$ cd test1
nmb@guttle[~/tmp/test1]$ echo "content" > file1
nmb@guttle[~/tmp/test1]$ bzr ci -m 'first trunk revision'
Committing to: /Users/nmb/tmp/test1/
aborting commit write group: PointlessCommit(No changes to commit)
bzr: ERROR: No changes to commit. Use --unchanged to commit anyhow.
nmb@guttle[~/tmp/test1]$ bzr add file1
adding file1
nmb@guttle[~/tmp/test1]$ bzr ci -m 'first trunk revision'
Committing to: /Users/nmb/tmp/test1/
added file1
Committed revision 1.
nmb@guttle[~/tmp/test1]$ cd ../test2
nmb@guttle[~/tmp/test2]$ bzr merge
Merging from remembered parent location /Users/nmb/tmp/test1/
+N file1
All changes applied successfully.
nmb@guttle[~/tmp/test2]$ bzr ci -m 'merge first revision'
Committing to: /Users/nmb/tmp/test2/
deleted
modified file1
Committed revision 1.
nmb@guttle[~/tmp/test2]$ cd ../test1
nmb@guttle[~/tmp/test1]$ bzr merge ../test2
All changes applied successfully.
nmb@guttle[~/tmp/test1]$ bzr st
pending merge tips: (use -v to see all merge revisions)
  Neil Martinsen-Bu... 2010-11-18 merge first revision
nmb@guttle[~/tmp/test1]$ bzr ci -m 'make the branches identical'
Committing to: /Users/nmb/tmp/test1/
Committed revision 2.
nmb@guttle[~/tmp/test1]$ echo "more contents" >> file1
nmb@guttle[~/tmp/test1]$ bzr ci -m 'trunk version'
Committing to: /Users/nmb/tmp/test1/
modified file1
Committed revision 3.
nmb@guttle[~/tmp/test1]$ cd ../test2
nmb@guttle[~/tmp/test2]$ echo "aggle flaggle klabble!" >> file1
-bash: !": event not found
nmb@guttle[~/tmp/test2]$ echo 'aggle flaggle klabble!' >> file1
nmb@guttle[~/tmp/test2]$ bzr ci -m 'branch revision'
Committing to: /Users/nmb/tmp/test2/
modified file1
Committed revision 2.
nmb@guttle[~/tmp/test2]$ cd ../test1
nmb@guttle[~/tmp/test1]$ bzr merge
Merging from remembered submit location /Users/nmb/tmp/test2/
 M file1
Text conflict in file1
1 conflicts encountered.
nmb@guttle[~/tmp/test1]$ bzr resolve --take-other file1
bzr: ERROR: exceptions.AttributeError: 'NoneType' object has no attribute 'lower'

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/commands.py", line 912, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/commands.py", line 1112, in run_bzr
    ret = run(*run_argv)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/commands.py", line 690, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/commands.py", line 705, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/conflicts.py", line 160, in run
    resolve(tree, file_list, action=action)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/conflicts.py", line 189, in resolve
    conflict._do(action, tree)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/conflicts.py", line 415, in _do
    meth(tree)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/conflicts.py", line 549, in action_take_other
    winner='other')
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/conflicts.py", line 444, in _resolve_with_cleanups
    op.run_simple(tt, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/cleanup.py", line 135, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/conflicts.py", line 508, in _resolve
    tt.apply()
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/transform.py", line 1516, in apply
    self._check_malformed()
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/transform.py", line 509, in _check_malformed
    conflicts = self.find_conflicts()
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/transform.py", line 500, in find_conflicts
    conflicts.extend(self._duplicate_entries(by_parent))
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/transform.py", line 642, in _duplicate_entries
    name_ids = [(n.lower(), t) for n, t in name_ids]
AttributeError: 'NoneType' object has no attribute 'lower'

bzr 2.3.0dev2 on python 2.6.5 (Darwin-10.4.0-i386-32bit)
arguments: ['/Library/Frameworks/Python.framework/Versions/Current/bin/bzr', 'resolve', '--take-other', 'file1']
encoding: 'UTF-8', fsenc: 'utf-8', lang: 'en_US.UTF-8'
plugins:
  automirror /Users/nmb/.bazaar/plugins/automirror [0.1.0]
  bash_completion /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/plugins/bash_completion [2.3.0dev2]
  bzrtools /Users/nmb/.bazaar/plugins/bzrtools [2.3.0]
  colo /Users/nmb/.bazaar/plugins/colo [0.2.1dev]
  deleted_log_formatter /Users/nmb/.bazaar/plugins/deleted_log_formatter.py [unknown]
  explorer /Users/nmb/.bazaar/plugins/explorer [1.1.2dev]
  fastimport /Users/nmb/.bazaar/plugins/fastimport [0.9.0dev]
  git /Users/nmb/.bazaar/plugins/git [0.5.3dev]
  hg /Users/nmb/.bazaar/plugins/hg [0.2.0dev]
  latex_version_info /Users/nmb/.bazaar/plugins/latex_version_info [0.0.2]
  launchpad /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/plugins/launchpad [2.3.0dev2]
  netrc_credential_store /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/plugins/netrc_credential_store [2.3.0dev2]
  news_merge /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/bzrlib/plugins/news_merge [2.3.0dev2]
  qbzr /Users/nmb/.bazaar/plugins/qbzr [0.20.0dev1]
  rst2html /Users/nmb/.bazaar/plugins/rst2html [0.0.2]

*** 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.