Dear Maintainer,

I can't use duplicity anymore.
For instance:
~$ duplicity collection-status $TARGET
Traceback (innermost last):
  File "/usr/bin/duplicity", line 92, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 75, in with_tempdir
    fn()
  File "/usr/lib/python3/dist-packages/duplicity/dup_main.py", line 1577, in
main
    do_backup(action)
  File "/usr/lib/python3/dist-packages/duplicity/dup_main.py", line 1599, in
do_backup
    action).set_values()
  File "/usr/lib/python3/dist-packages/duplicity/dup_collections.py", line 761,
in set_values
    self.set_matched_chain_pair(local_sig_chains + remote_sig_chains,
  File "/usr/lib/python3/dist-packages/duplicity/dup_collections.py", line 775,
in set_matched_chain_pair
    sig_chains = sig_chains and self.get_sorted_chains(sig_chains)
  File "/usr/lib/python3/dist-packages/duplicity/dup_collections.py", line 992,
in get_sorted_chains
    assert len(chain_list) == 2
 AssertionError


What's wrong? What should I do?

Best regards

severity 1012389 normal
forwarded 1012389 https://bugs.launchpad.net/duplicity/+bug/1499990
tags 1012389 + moreinfo
thanks

On Mon, 06 Jun 2022 10:50:27 +0200, Christophe Lohr writes:
...

looks like you've run into yet another long-unfixed problem that
upstream is ignoring; see the link to the upstream bug report.

apparently long-running and/or often-retried backups can lead to duplicity
losing its smarts.

i don't know.

i suspect you might get somewhere with a clean slate, ie.
after renaming all of your current backups *and* the cache directories.

to go any further it'll be necessary that you

a) report your full duplicity invocation (without that i have no clue
what backend you're using, whether this was a full backup
only or incremental or whatever)

and b) reproduce the problem from a clean state, run duplicity with -v9 and
provide the resulting log as well (minus personal/private information).

Hi Alexander,
   Many thanks for your answers.

duplicity does the full backup normally
The issue occurs while trying to do an incremental backup

On my setup, the backend is a cifs partition mounted locally

Well, I hopefully have found a workaround:  With the option
"--no-encryption" duplicity makes full and incremental backups as usual
(except ciphering, which is not really a point in my case. I just need
no to lose data)
Obviously, duplicity encounters some bad interactions with possible
recent updates of gpg...

Best regards
Christophe