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.