3 files changed, 20 insertions, 14 deletions
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 8a9dcb2fc2..fc1874b65b 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -31,6 +31,9 @@ import functools
 import inspect
 import threading
 
+from six import string_types, itervalues
+import six
+
 
 logger = logging.getLogger(__name__)
 
@@ -205,7 +208,7 @@ class Cache(object):
     def invalidate_all(self):
         self.check_thread()
         self.cache.clear()
-        for entry in self._pending_deferred_cache.itervalues():
+        for entry in itervalues(self._pending_deferred_cache):
             entry.invalidate()
         self._pending_deferred_cache.clear()
 
@@ -392,9 +395,10 @@ class CacheDescriptor(_CacheDescriptorBase):
 
                 ret.addErrback(onErr)
 
-                # If our cache_key is a string, try to convert to ascii to save
-                # a bit of space in large caches
-                if isinstance(cache_key, basestring):
+                # If our cache_key is a string on py2, try to convert to ascii
+                # to save a bit of space in large caches. Py3 does this
+                # internally automatically.
+                if six.PY2 and isinstance(cache_key, string_types):
                     cache_key = to_ascii(cache_key)
 
                 result_d = ObservableDeferred(ret, consumeErrors=True)
@@ -565,7 +569,7 @@ class CacheListDescriptor(_CacheDescriptorBase):
                     return results
 
                 return logcontext.make_deferred_yieldable(defer.gatherResults(
-                    cached_defers.values(),
+                    list(cached_defers.values()),
                     consumeErrors=True,
                 ).addCallback(update_results_dict).addErrback(
                     unwrapFirstError
diff --git a/synapse/util/caches/treecache.py b/synapse/util/caches/treecache.py
index fcc341a6b7..dd4c9e6067 100644
--- a/synapse/util/caches/treecache.py
+++ b/synapse/util/caches/treecache.py
@@ -1,3 +1,5 @@
+from six import itervalues
+
 SENTINEL = object()
 
 
@@ -49,7 +51,7 @@ class TreeCache(object):
         if popped is SENTINEL:
             return default
 
-        node_and_keys = zip(nodes, key)
+        node_and_keys = list(zip(nodes, key))
         node_and_keys.reverse()
         node_and_keys.append((self.root, None))
 
@@ -76,7 +78,7 @@ def iterate_tree_cache_entry(d):
     can contain dicts.
     """
     if isinstance(d, dict):
-        for value_d in d.itervalues():
+        for value_d in itervalues(d):
             for value in iterate_tree_cache_entry(value_d):
                 yield value
     else:
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index f497b51f4a..15f0a7ba9e 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -16,16 +16,17 @@
 from frozendict import frozendict
 import simplejson as json
 
+from six import string_types
+
 
 def freeze(o):
-    t = type(o)
-    if t is dict:
+    if isinstance(o, dict):
         return frozendict({k: freeze(v) for k, v in o.items()})
 
-    if t is frozendict:
+    if isinstance(o, frozendict):
         return o
 
-    if t is str or t is unicode:
+    if isinstance(o, string_types):
         return o
 
     try:
@@ -37,11 +38,10 @@ def freeze(o):
 
 
 def unfreeze(o):
-    t = type(o)
-    if t is dict or t is frozendict:
+    if isinstance(o, (dict, frozendict)):
         return dict({k: unfreeze(v) for k, v in o.items()})
 
-    if t is str or t is unicode:
+    if isinstance(o, string_types):
         return o
 
     try: