From 627b97c317a6c3ceafa1c8f1192633d1c85c93ff Mon Sep 17 00:00:00 2001
From: Andrew Godwin <andrew@aeracode.org>
Date: Mon, 3 Apr 2017 13:01:20 +0200
Subject: [PATCH] Fixed #588: enforce_ordering failed to wait on
 process-specific chans

---
 channels/sessions.py   | 13 +++++++++++--
 tests/test_sessions.py |  8 ++++----
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/channels/sessions.py b/channels/sessions.py
index 3e43f80..8bf716b 100644
--- a/channels/sessions.py
+++ b/channels/sessions.py
@@ -83,12 +83,21 @@ def channel_session(func):
     return inner
 
 
+def wait_channel_name(reply_channel):
+    """
+    Given a reply_channel, returns a wait channel for it.
+    Replaces any ! with ? so process-specific channels become single-reader
+    channels.
+    """
+    return "__wait__.%s" % (reply_channel.replace("!", "?"), )
+
+
 def requeue_messages(message):
     """
     Requeue any pending wait channel messages for this socket connection back onto it's original channel
     """
     while True:
-        wait_channel = "__wait__.%s" % message.reply_channel.name
+        wait_channel = wait_channel_name(message.reply_channel.name)
         channel, content = message.channel_layer.receive_many([wait_channel], block=False)
         if channel:
             original_channel = content.pop("original_channel")
@@ -137,7 +146,7 @@ def enforce_ordering(func=None, slight=False):
                 requeue_messages(message)
             else:
                 # Since out of order, enqueue message temporarily to wait channel for this socket connection
-                wait_channel = "__wait__.%s" % message.reply_channel.name
+                wait_channel = wait_channel_name(message.reply_channel.name)
                 message.content["original_channel"] = message.channel.name
                 try:
                     message.channel_layer.send(wait_channel, message.content)
diff --git a/tests/test_sessions.py b/tests/test_sessions.py
index d1d507a..007ae98 100644
--- a/tests/test_sessions.py
+++ b/tests/test_sessions.py
@@ -256,17 +256,17 @@ class SessionTests(ChannelTestCase):
         """
         # Construct messages to send
         message0 = Message(
-            {"reply_channel": "test-reply-b", "order": 0},
+            {"reply_channel": "test-reply!b", "order": 0},
             "websocket.connect",
             channel_layers[DEFAULT_CHANNEL_LAYER]
         )
         message1 = Message(
-            {"reply_channel": "test-reply-b", "order": 1},
+            {"reply_channel": "test-reply!b", "order": 1},
             "websocket.receive",
             channel_layers[DEFAULT_CHANNEL_LAYER]
         )
         message2 = Message(
-            {"reply_channel": "test-reply-b", "order": 2},
+            {"reply_channel": "test-reply!b", "order": 2},
             "websocket.receive",
             channel_layers[DEFAULT_CHANNEL_LAYER]
         )
@@ -281,7 +281,7 @@ class SessionTests(ChannelTestCase):
         inner(message2)
 
         # Ensure wait channel is empty
-        wait_channel = "__wait__.%s" % "test-reply-b"
+        wait_channel = "__wait__.test-reply?b"
         next_message = self.get_next_message(wait_channel)
         self.assertEqual(next_message, None)