Merge lp:~mterry/duplicity/pydrive-cache-fix into lp:~duplicity-team/duplicity/0.8-series

[Michael Terry]

The pydrive backend had another of the ongoing bytes/string issues. :)

This time, it was saving a bytes filename in its internal cache after each volume upload. Then when asked for a list of files later, it would add the byte-filenames from its cache to the results. And we'd end up thinking there were two of the same filename on the backend, which would cause a crash at the end of an otherwise successful backup, because the collections code would assert on the filenames being unique.

=== modified file 'duplicity/backends/pydrivebackend.py'
--- duplicity/backends/pydrivebackend.py	2019-06-17 18:58:56 +0000
+++ duplicity/backends/pydrivebackend.py	2019-11-13 02:22:24 +0000
@@ -166,16 +166,17 @@
             return drive_file[u'id']
 
     def _put(self, source_path, remote_filename):
+        remote_filename = util.fsdecode(remote_filename)
         drive_file = self.file_by_name(remote_filename)
         if drive_file is None:
             # No existing file, make a new one
-            drive_file = self.drive.CreateFile({u'title': util.fsdecode(remote_filename),
+            drive_file = self.drive.CreateFile({u'title': remote_filename,
                                                 u'parents': [{u"kind": u"drive#fileLink",
                                                              u"id": self.folder}]})
-            log.Info(u"PyDrive backend: creating new file '%s'" % (util.fsdecode(remote_filename),))
+            log.Info(u"PyDrive backend: creating new file '%s'" % (remote_filename,))
         else:
             log.Info(u"PyDrive backend: replacing existing file '%s' with id '%s'" % (
-                util.fsdecode(remote_filename), drive_file[u'id']))
+                remote_filename, drive_file[u'id']))
         drive_file.SetContentFile(util.fsdecode(source_path.name))
         drive_file.Upload()
         self.id_cache[remote_filename] = drive_file[u'id']