Some progress towards passing Python 3 tests.

src/allmydata/scripts/common.py

@@ -1,7 +1,7 @@
 # coding: utf-8
 
 from __future__ import print_function
-from six import ensure_binary
+from six import ensure_str
 
 import os, sys, textwrap
 import codecs
@@ -276,17 +276,27 @@ def get_alias(aliases, path_unicode, default):
     return uri.from_string_dirnode(aliases[alias]).to_string(), path[colon+1:]
 
 def escape_path(path):
-    # type: (Union[str,bytes]) -> bytes
+    # type: (Union[str,bytes]) -> str
     u"""
     Return path quoted to US-ASCII, valid URL characters.
 
     >>> path = u'/føö/bar/☃'
     >>> escaped = escape_path(path)
     >>> escaped
-    b'/f%C3%B8%C3%B6/bar/%E2%98%83'
+    u'/f%C3%B8%C3%B6/bar/%E2%98%83'
     """
     if isinstance(path, str):
         path = path.encode("utf-8")
     segments = path.split(b"/")
-    return b"/".join([urllib.parse.quote(s).encode("ascii") for s in segments])
-
+    result = str(
+        b"/".join([
+            urllib.parse.quote(s).encode("ascii") for s in segments
+        ]),
+        "ascii"
+    )
+    # Eventually (i.e. as part of Python 3 port) we want this to always return
+    # Unicode strings. However, to reduce diff sizes in the short term it'll
+    # return native string (i.e. bytes) on Python 2.
+    if PY2:
+        result = result.encode("ascii").__native__()
+    return result

src/allmydata/scripts/tahoe_backup.py

@@ -1,5 +1,7 @@
 from __future__ import print_function
 
+from past.builtins import unicode
+
 import os.path
 import time
 from urllib.parse import quote as url_quote
@@ -345,7 +347,7 @@ class FileTarget(object):
             target = PermissionDeniedTarget(self._path, isdir=False)
             return target.backup(progress, upload_file, upload_directory)
         else:
-            assert isinstance(childcap, str)
+            assert isinstance(childcap, bytes)
             if created:
                 return progress.created_file(self._path, childcap, metadata)
             return progress.reused_file(self._path, childcap, metadata)
@@ -525,12 +527,12 @@ class BackupProgress(object):
         return self, {
             os.path.basename(create_path): create_value
             for (create_path, create_value)
-            in self._create_contents.iteritems()
+            in self._create_contents.items()
             if os.path.dirname(create_path) == dirpath
         }, {
             os.path.basename(compare_path): compare_value
             for (compare_path, compare_value)
-            in self._compare_contents.iteritems()
+            in self._compare_contents.items()
             if os.path.dirname(compare_path) == dirpath
         }