AssertionError in patch_seq2ropath

[esskov]

I'm trying to restore a backup consisting of 1 full backup and 4 incremental, but duplicity exits with an assertion error while writing the restored files.
One of the incremental backup operations was interrupted due to a read-error on the source file system. Could that be the cause of the problem? Anyhow, as the source disk has now died, it's important to me that duplicity could somehow complete the restore operation. Using --ignore-errors seems to make no difference here.

The particular assertion error is similar to the one in Bug #531178, however in my case the backup as well as the restore is with duplicity 0.6.

Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1262, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1255, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1209, in main
    restore(col_stats)
  File "/usr/bin/duplicity", line 539, in restore
    restore_get_patched_rop_iter(col_stats)):
  File "/usr/lib/python2.6/dist-packages/duplicity/patchdir.py", line 521, in Write_ROPaths
    for ropath in rop_iter:
  File "/usr/lib/python2.6/dist-packages/duplicity/patchdir.py", line 494, in integrate_patch_iters
    final_ropath = patch_seq2ropath( normalize_ps( patch_seq ) )
  File "/usr/lib/python2.6/dist-packages/duplicity/patchdir.py", line 461, in patch_seq2ropath
    assert first.difftype != "diff", patch_seq
AssertionError: [(('a', 'b', 'c') reg)]

================================================================================
duplicity 0.6.13 (April 02, 2011)
Args: /usr/bin/duplicity restore --no-encryption --file-to-restore xxx file:///yyy/ /zzz
Linux xxx 2.6.35-28-generic-pae #50-Ubuntu SMP Fri Mar 18 20:43:15 UTC 2011 i686
/usr/bin/python 2.6.6 (r266:84292, Sep 15 2010, 15:52:39)
[GCC 4.4.5]