duplicity crash: "assert len(chain_list) == 2"

[Stephen N. DeWitt, OFM]

Ubuntu 10.10 (64 bit)
Deja-Dup 16.1.1-0ubuntu1
duplicity 0.6.10-0ubuntu1

I am trying to restore files from a backup on an external hardrive (NTFS). Every time I run the restore program it fails with an unknown error and gives the following output:

Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1257, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1250, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1155, in main
    globals.archive_dir).set_values()
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 687, in set_values
    backup_chains)
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 700, in set_matched_chain_pair
    sig_chains = sig_chains and self.get_sorted_chains(sig_chains)
  File "/usr/lib/python2.6/dist-packages/duplicity/collections.py", line 913, in get_sorted_chains
    assert len(chain_list) == 2
AssertionError

I made the backup with the 32 bit version of 10.10 if that makes a difference.

[Stephen N. DeWitt, OFM (sdewittofm)]

deja-dup.gconf

[Michael Terry (mterry)]

That's an odd error. Can you give me a list of all the duplicity- files on the external drive?

[Stephen N. DeWitt, OFM (sdewittofm)]

I have attached a file with the list.

[Michael Terry (mterry)]

I think there are two possibilities.
 1) The file 'duplicity-full-signatures.20110129T144142Z.sigtar' is odd. I believe it shouldn't be there on the drive. Try moving that out of the way and trying again.
 2) Your local cache of the remote files is somehow out of sync. To test this, move ~/.cache/duplicity out of the way and try again.

I'd say try #1 first. If it fails, move it back onto the drive and try #2. Let me know how it goes.

[Michael Terry (mterry)]

(to be specific about my #1, the version of that file with the .gpg ending is good and expected. I thought it was odd that there was a version without the .gpg suffix)

[Stephen N. DeWitt, OFM (sdewittofm)]

#1 seems to have fixed the problem and the restore is in process now. Many thanks, I have 6 months of files in that backup that are not available elsewhere.

[Michael Terry (mterry)]

Awesome! It would still be good to figure out why that non-gpg suffixed file was there, but good that you can get your data.

Ken, do you have ideas about why a non-gpg sigtar would appear in the backup?

[Kenneth Loafman (kenneth-loafman)]

Not a clue. A temp file, maybe, that did not get deleted and duplicity ignored the error.

[Lark (florent-g)]

Same crash and error message here, both when restoring and backuping data.

I couldn't try trick #1 because I don't have any non-gpg sigtar in my backup
I tried trick #2, then launched a backup operation, and this deleted my whole backup data.

Could you tell me which informations are important for you to work on this bug ?

Regards