Bug#1012389: duplicity: Can't backup anymore - AssertionError

[Christophe Lohr]

Package: duplicity
Version: 0.8.22-1
Severity: important
Tags: upstream

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


-- System Information:
Debian Release: bookworm/sid
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'proposed-updates'), (500, 'oldstable-updates'), (500, 'oldoldstable'), (500, 'testing'), (500, 'stable'), (500, 'oldstable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.17.0-1-amd64 (SMP w/4 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages duplicity depends on:
ii gnupg 2.2.35-2
ii libc6 2.33-7
ii librsync2 2.3.2-1+b1
ii python3 3.10.4-1+b1
ii python3-fasteners 0.17.3-2
ii python3-future 0.18.2-6
ii python3-lockfile 1:0.12.2-2.2
ii python3.10 3.10.4-1

Versions of packages duplicity recommends:
ii python3-oauthlib 3.2.0-1
ii python3-paramiko 2.8.1-1
ii python3-pexpect 4.8.0-3
ii python3-urllib3 1.26.9-1
ii rsync 3.2.4-1

Versions of packages duplicity suggests:
ii lftp 4.9.2-1+b1
ii ncftp 2:3.2.5-2.2
pn par2 <none>
pn python3-boto <none>
ii python3-pip 22.1.1+dfsg-1
pn python3-swiftclient <none>
pn tahoe-lafs <none>

-- no debconf information

[Alexander Zangerl]

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:
...

>in get_sorted_chains
> assert len(chain_list) == 2
> AssertionError

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.

>What's wrong?

i don't know.

> What should I do?

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).


--
Alexander Zangerl + GPG Key 2FCCF66BB963BD5F + http://snafu.priv.at/
The determined programmer can write a FORTRAN program in any language.

[Christophe Lohr]

Hi Alexander,
  Many thanks for your answers.

> 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)

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

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

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