Fix 'list-current-files' with missing archive dir

[Henry Ludemann]

When running 'list-current-files' using '--archive-dir' when the archive dir doesn't exist, the commands fails with an encryption error.

Steps to reproduce;

 $ mkdir source
 $ touch source/test
 $ duplicity source backup
 $ mkdir cache
 $ duplicity list-current-files --archive-dir ./cache backup
  ===== Begin GnuPG log =====
  gpg: CAST5 encrypted data
  gpg: encrypted with 1 passphrase
  gpg: decryption failed: bad key
  ===== End GnuPG log ====

This is because there is an 'early out' in the password handling that checks to see if we are running 'list-current-files' with a local archive, in which case it doesn't ask for the password. This is wrong in this case because even though the archive exists, it doesn't have any signature files.

The attached patch moves the password querying to separate module which only asks the user for the password when it is required. As the signature file class correctly falls back to the backend when the files aren't available in the cache, this fixes the bug (as well as removes a bunch of special case checks for when the password needs to be read).

[Kenneth Loafman (kenneth-loafman)]

This was fixed in 0.6.1 with the addition of automatic archive sync at startup.

[Henry Ludemann (misc-hl)]

Just tested with a clean version of 0.6.01; this is still broken (follow the steps listed in the initial comment, but fix the url used for the backup path). eg:

 $ mkdir source
 $ touch source/test
 $ duplicity source file://`pwd`/backup
 $ mkdir cache
 $ duplicity list-current-files --archive-dir ./cache file://`pwd`/backup

The password handling code in 0.6.01 still does the early out when running 'list-current-files', which is incorrect when the archive dir doesn't exist.

The previously attached fix no longer applies due to the changes in the password handling in 0.6.01.

[Kenneth Loafman (kenneth-loafman)]

Will take another look at your patch and see if there are other problems. We've been down the password problem road a bunch in previous revisions, lots of borked releases due to password complexity issues.

[Kenneth Loafman (kenneth-loafman)]

This will fix this issue and others that have empty archive dirs and
encrypted remote storage.