qdiff crashes

[Bernhard Voelker]

Win7, 64bit, rather new repo (revno==2).
`bzr st` reports 6 of 900 version files as modified.

The crash happens under 2.5.0 and 2.6b1, immediately after startup of qdi,
and also if called from the diff button in `bzr qci` and from 'bzr explorer'.

However, a command line `bzr diff` works.

Reading other reports, this seems to be a duplicate of https://bugs.launchpad.net/qbzr/+bug/839053.

bzr qdi
bzr: ERROR: exceptions.IndexError: pop from empty list

Traceback (most recent call last):
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\trace.py", line 365, in reports_exception_decorate
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\diffwindow.py", line 366, in initial_load
  File "bzrlib\cleanup.pyo", line 132, in run
  File "bzrlib\cleanup.pyo", line 166, in _do_with_cleanups
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\diffwindow.py", line 380, in _initial_load
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\diffwindow.py", line 447, in load_diff
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\diffview.py", line 669, in append_diff
  File "C:/Program Files (x86)/Bazaar/plugins\qbzr\lib\diffview.py", line 617, in insertIxsWithChangesHighlighted
IndexError: pop from empty list

bzr 2.6b1 on python 2.6.6 (Windows-7-6.1.7601-SP1)
arguments: ['bzr', 'qdi']
plugins: bzrtools[2.5.0], changelog_merge[2.6b1], colo[0.4.0],
    explorer[1.3.0dev], fastimport[0.14.0dev], git[0.6.8dev],
    launchpad[2.6b1], loom[2.3.0dev], netrc_credential_store[2.6b1],
    news_merge[2.6b1], pipeline[1.4.0], qbzr[0.23.0dev], rewrite[0.6.4dev],
    svn[1.2.2dev], upload[1.2.0dev], xmloutput[0.8.8]
encoding: 'cp1252', fsenc: 'mbcs', lang: None

*** 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.

[Martin Packman (gz)]

Thanks for the report, see the existing bug for more details.