Merge tag 'v0.33.3rc2' into matrix-org-hotfixes

Bugfixes
--------

- Fix bug in v0.33.3rc1 which caused infinite loops and OOMs
([\#3723](https://github.com/matrix-org/synapse/issues/3723))

1 files changed, 15 insertions, 0 deletions

diff --git a/synapse/util/stringutils.py b/synapse/util/stringutils.py

index 43d9db67ec..6f318c6a29 100644
--- a/synapse/util/stringutils.py
+++ b/synapse/util/stringutils.py
@@ -16,6 +16,7 @@
 import random
 import string
 
+from six import PY3
 from six.moves import range
 
 _string_with_symbols = (
@@ -34,6 +35,17 @@ def random_string_with_symbols(length):
 
 
 def is_ascii(s):
+
+    if PY3:
+        if isinstance(s, bytes):
+            try:
+                s.decode('ascii').encode('ascii')
+            except UnicodeDecodeError:
+                return False
+            except UnicodeEncodeError:
+                return False
+            return True
+
     try:
         s.encode("ascii")
     except UnicodeEncodeError:
@@ -49,6 +61,9 @@ def to_ascii(s):
 
     If given None then will return None.
     """
+    if PY3:
+        return s
+
     if s is None:
         return None