[Duplicity-talk] InvalidBackendURL for multi backend

[Tom]

Hi,

I updated to duplicity 0.8.05 on Fedora 31 and there seems to either be
a bug or a backwards-incompatible change. When I try to interact with a
multi backend I get the following error:

$ duplicity collection-status
'multi:///home/tom/duplicity.json?mode=mirror'
InvalidBackendURL: Syntax error (path) in:
b'file:///home/tom/second_drive/backup/'

My duplicity.json contains the following contents:

[
    {
        "description": "second drive",
        "url": "file:///home/tom/second_drive/backup/"
    },
    {
        "description": "third drive",
        "url": "file:///home/tom/third_drive/backup/"
    }
]

Using 'file:///home/tom/second_drive/backup/' directly seems to work
fine, so the problem seems to be related to the multi backend. Here is
a full stack trace:

MultiBackend: use store b'file:///home/tom/second_drive/backup/'
Using temporary directory /tmp/duplicity-q8pkrkbc-tempdir
User error detail: Traceback (innermost last):
  File "/usr/bin/duplicity", line 101, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 87, in with_tempdir
    fn()
  File "/usr/lib64/python3.7/site-packages/duplicity/dup_main.py", line
1519, in main
    action = commandline.ProcessCommandLine(sys.argv[1:])
  File "/usr/lib64/python3.7/site-packages/duplicity/commandline.py",
line 1203, in ProcessCommandLine
    globals.backend = backend.get_backend(args[0])
  File "/usr/lib64/python3.7/site-packages/duplicity/backend.py", line
225, in get_backend
    obj = get_backend_object(url_string)
  File "/usr/lib64/python3.7/site-packages/duplicity/backend.py", line
211, in get_backend_object
    return factory(pu)
  File "/usr/lib64/python3.7/site-
packages/duplicity/backends/multibackend.py", line 197, in __init__
    store = duplicity.backend.get_backend(url)
  File "/usr/lib64/python3.7/site-packages/duplicity/backend.py", line
225, in get_backend
    obj = get_backend_object(url_string)
  File "/usr/lib64/python3.7/site-packages/duplicity/backend.py", line
188, in get_backend_object
    if not is_backend_url(url_string):
  File "/usr/lib64/python3.7/site-packages/duplicity/backend.py", line
172, in is_backend_url
    pu = ParsedUrl(url_string)
  File "/usr/lib64/python3.7/site-packages/duplicity/backend.py", line
274, in __init__
    raise InvalidBackendURL(u"Syntax error (path) in: %s" % url_string)
 duplicity.errors.InvalidBackendURL: Syntax error (path) in:
b'file:///home/tom/second_drive/backup/'