From d6a7797dd1d76a86e6914c2ae562fa83eee4c57f Mon Sep 17 00:00:00 2001
From: Will Hunt <will@half-shot.uk>
Date: Wed, 17 Oct 2018 13:04:55 +0100
Subject: [PATCH] Fix roomlist since tokens on Python 3 (#4046)

Thanks @Half-Shot !!!
---
 changelog.d/4046.bugfix         |  1 +
 synapse/handlers/room_list.py   | 11 ++++++++--
 synapse/python_dependencies.py  |  2 +-
 tests/handlers/test_roomlist.py | 39 +++++++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100644 changelog.d/4046.bugfix
 create mode 100644 tests/handlers/test_roomlist.py

diff --git a/changelog.d/4046.bugfix b/changelog.d/4046.bugfix
new file mode 100644
index 0000000000..5046dd1ce3
--- /dev/null
+++ b/changelog.d/4046.bugfix
@@ -0,0 +1 @@
+Fix issue where Python 3 users couldn't paginate /publicRooms
diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py
index 38e1737ec9..dc88620885 100644
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@@ -16,7 +16,7 @@
 import logging
 from collections import namedtuple
 
-from six import iteritems
+from six import PY3, iteritems
 from six.moves import range
 
 import msgpack
@@ -444,9 +444,16 @@ class RoomListNextBatch(namedtuple("RoomListNextBatch", (
 
     @classmethod
     def from_token(cls, token):
+        if PY3:
+            # The argument raw=False is only available on new versions of
+            # msgpack, and only really needed on Python 3. Gate it behind
+            # a PY3 check to avoid causing issues on Debian-packaged versions.
+            decoded = msgpack.loads(decode_base64(token), raw=False)
+        else:
+            decoded = msgpack.loads(decode_base64(token))
         return RoomListNextBatch(**{
             cls.REVERSE_KEY_DICT[key]: val
-            for key, val in msgpack.loads(decode_base64(token)).items()
+            for key, val in decoded.items()
         })
 
     def to_token(self):
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 2947f37f1a..f51184b50d 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -55,7 +55,7 @@ REQUIREMENTS = {
     "sortedcontainers>=1.4.4": ["sortedcontainers"],
     "pysaml2>=3.0.0": ["saml2"],
     "pymacaroons-pynacl>=0.9.3": ["pymacaroons"],
-    "msgpack-python>=0.3.0": ["msgpack"],
+    "msgpack-python>=0.4.2": ["msgpack"],
     "phonenumbers>=8.2.0": ["phonenumbers"],
     "six>=1.10": ["six"],
 
diff --git a/tests/handlers/test_roomlist.py b/tests/handlers/test_roomlist.py
new file mode 100644
index 0000000000..61eebb6985
--- /dev/null
+++ b/tests/handlers/test_roomlist.py
@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from synapse.handlers.room_list import RoomListNextBatch
+
+import tests.unittest
+import tests.utils
+
+
+class RoomListTestCase(tests.unittest.TestCase):
+    """ Tests RoomList's RoomListNextBatch. """
+
+    def setUp(self):
+        pass
+
+    def test_check_read_batch_tokens(self):
+        batch_token = RoomListNextBatch(
+            stream_ordering="abcdef",
+            public_room_stream_id="123",
+            current_limit=20,
+            direction_is_forward=True,
+        ).to_token()
+        next_batch = RoomListNextBatch.from_token(batch_token)
+        self.assertEquals(next_batch.stream_ordering, "abcdef")
+        self.assertEquals(next_batch.public_room_stream_id, "123")
+        self.assertEquals(next_batch.current_limit, 20)
+        self.assertEquals(next_batch.direction_is_forward, True)