Merge commits in branch of subversion repository crash on diffing

[Huw Giddens]

I've been using a workflow like:
    bzr init-repo bzr-repo
    bzr branch http://svn-repo/trunk bzr-repo/trunk
    bzr branch bzr-repo/trunk bzr-repo/feature
    hack on bzr-repo/feature
    cd bzr-repo/trunk
    bzr merge ../feature
    bzr push http://svn-repo/trunk

Trying to run bzr diff either on the merge commit (via -c) or across it (-r before:X..X) from a separate bzr repository results in bzr crashing:
bzr: ERROR: bzrlib.errors.NoSuchRevision: CHKInventoryRepository('file:///home/giddens/reproduce/unrelated-repository/.bzr/repository/') has no revision giddens@quills-20091021034530-1414x7xj7ioy7q85

[Huw Giddens (hgiddens)]

Steps to reproduce:
[giddens@quills 501 ~]$ mkdir reproduce
[giddens@quills 502 ~]$ cd !$
cd reproduce
[giddens@quills 503 reproduce]$ svnadmin create svn-repository
[giddens@quills 504 reproduce]$ svn co file://$PWD/svn-repository svn-sandbox
Checked out revision 0.
[giddens@quills 505 reproduce]$ (cd svn-sandbox && echo 'initial commit' > file && svn add file && svn ci -m 'initial commit')
A file
Adding file
Transmitting file data .
Committed revision 1.
[giddens@quills 506 reproduce]$ bzr init-repo bzr-repository
Shared repository with trees (format: 2a)
Location:
  shared repository: bzr-repository
[giddens@quills 507 reproduce]$ (cd bzr-repository && bzr branch file://$PWD/../svn-repository)
Initialising Subversion metadata cache in /home/giddens/.bazaar/svn-cache/8416993f-88bb-4b5e-bf51-df751838e050.
Branched 2 revision(s).
[giddens@quills 508 reproduce]$ mv bzr-repository/{svn-repository,trunk}
[giddens@quills 509 reproduce]$ (cd bzr-repository/trunk && echo 'change from trunk' >> file && bzr ci -m 'change from trunk')
Committing to: /home/giddens/reproduce/bzr-repository/trunk/
modified file
Committed revision 3.
[giddens@quills 510 reproduce]$ (cd bzr-repository && bzr branch trunk feature)
Branched 3 revision(s).
[giddens@quills 511 reproduce]$ (cd bzr-repository/feature && echo 'change from feature' >> file && bzr ci -m 'change from feature')
Committing to: /home/giddens/reproduce/bzr-repository/feature/
modified file
Committed revision 4.
[giddens@quills 512 reproduce]$ (cd bzr-repository/trunk && bzr merge ../feature && bzr ci -m 'merged feature branch')
 M file
All changes applied successfully.
Committing to: /home/giddens/reproduce/bzr-repository/trunk/
modified file
Committed revision 4.
[giddens@quills 513 reproduce]$ (cd bzr-repository/trunk && echo 'subsequent change in trunk' >> file && bzr ci -m 'subsequent change in trunk' && bzr push file://$PWD/../../svn-repository)
Committing to: /home/giddens/reproduce/bzr-repository/trunk/
modified file
Committed revision 5.
Pushed up to revision 5.
[giddens@quills 515 reproduce]$ bzr init-repo unrelated-repository
Shared repository with trees (format: 2a)
Location:
  shared repository: unrelated-repository
[giddens@quills 517 reproduce]$ (cd unrelated-repository/ && bzr branch file://$PWD/../svn-repository trunk-two)
Branched 5 revision(s).
[giddens@quills 519 reproduce]$ (cd unrelated-repository/trunk-two && bzr diff -c 4)
==...

[Huw Giddens (hgiddens)]

I've tried using the various other rich-root repository formats, not using shared repositories, using r3200 of lp:bzr-svn, and using older versions of Bazaar (1.13 and 1.18, with appropriate vintage bzr-svn). All crash when I try to view the diff.