duplicity crashes since upgraded to 19.10

[Tommy Pollák]

The following script is used to run duplicity for backup

# Version PA01/01 by T Pollák on 2018-11-02
# This script is used to create a full backup of this computer
# and must be run as root.
# The script will run the backup command duplicity to create
# a full backup on My Book Live as IP 192.168.1.100 with ftp
# into the directory 64HP in the share Tommy.
# The script is developed from the script backup_duplicity_full64.
# To create incremental backups run the script
# /home/tpollak/bin/backup_duplicity_incrHP as root.
# - - - - - -

PASSPHRASE=*******
FTP_PASSWORD=****
export PASSPHRASE FTP_PASSWORD

duplicity full --force --volsize 1000 --exclude /media/OS/Program\ Files/WindowsApps --exclude /media/OS/Windows --exclude /boot --exclude /cdrom --exclude /dev --exclude /proc --exclude /sys --exclude /tmp --exclude /home/tpollak/.gvfs --exclude /run/user/1000/gvfs --exclude /home/tpollak/Downloads --exclude /home/tpollak/Trash / ftp://Tommy@192.168.1.100/Tommy/64HP

This looks like the following in the terminal

~$ sudo bin/backup_duplicity_fullHP
LFTP version is 4.8.4
Local and Remote metadata are synchronized, no sync needed.
Last full backup date: Tue Oct 1 11:56:24 2019
Traceback (innermost last):
  File "/usr/bin/duplicity", line 107, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 93, in with_tempdir
    fn()
  File "/usr/lib/python3/dist-packages/duplicity/dup_main.py", line 1535, in main
    do_backup(action)
  File "/usr/lib/python3/dist-packages/duplicity/dup_main.py", line 1659, in do_backup
    full_backup(col_stats)
  File "/usr/lib/python3/dist-packages/duplicity/dup_main.py", line 565, in full_backup
    globals.backend)
  File "/usr/lib/python3/dist-packages/duplicity/dup_main.py", line 422, in write_multivol
    globals.volsize)
  File "/usr/lib/python3/dist-packages/duplicity/gpg.py", line 393, in GPGWriteFile
    data = block_iter.__next__().data
  File "/usr/lib/python3/dist-packages/duplicity/diffdir.py", line 542, in __next__
    result = self.process(next(self.input_iter)) # pylint: disable=assignment-from-no-return
  File "/usr/lib/python3/dist-packages/duplicity/diffdir.py", line 680, in process
    data, last_block = self.get_data_block(fp)
  File "/usr/lib/python3/dist-packages/duplicity/diffdir.py", line 707, in get_data_block
    buf = fp.read(read_size)
  File "/usr/lib/python3/dist-packages/duplicity/diffdir.py", line 449, in read
    buf = self.infile.read(length)
  File "/usr/lib/python3/dist-packages/duplicity/diffdir.py", line 417, in read
    log.Warn(_(u"Error %s getting delta for %s") % (str(ex), self.infile.uc_name))
 AttributeError: '_io.BufferedReader' object has no attribute 'uc_name'

~$

Below is an excerpt from a listing of the backup directory

......
ftp> open 192.168.1.100
ftp> cd Tommy/64HP
ftp> ls
......
-rwxr-xr-x 1 ftp ftp 1048607916 Dec 01 23:38 duplicity-full.20191201T135308Z.vol102.difftar.gpg
-rwxr-xr-x 1 ftp ftp 1048616177 Dec 01 23:43 duplicity-full.20191201T135308Z.vol103.difftar.gpg
-rwxr-xr-x 1 ftp ftp 1048608039 Dec 01 23:47 duplicity-full.20191201T135308Z.vol104.difftar.gpg
-rwxr-xr-x 1 ftp ftp 504667096 Dec 01 23:49 duplicity-full.20191201T135308Z.vol105.difftar.gpg
-rwxr-xr-x 1 ftp ftp 1048619424 Dec 01 15:49 duplicity-full.20191201T135308Z.vol11.difftar.gpg

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: duplicity 0.8.04-2ubuntu1
ProcVersionSignature: Ubuntu 5.3.0-23.25-generic 5.3.7
Uname: Linux 5.3.0-23-generic x86_64
ApportVersion: 2.20.11-0ubuntu8.2
Architecture: amd64
CurrentDesktop: XFCE
Date: Mon Dec 2 15:16:02 2019
InstallationDate: Installed on 2018-10-12 (415 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
SourcePackage: duplicity
UpgradeStatus: Upgraded to eoan on 2019-10-29 (33 days ago)