Fix do_rename_stream to update the stream's email address.

This change also makes it so that the test_rename_stream()
test exercises the code path.  We need to subscribe the user
to the stream in order to generate events.

(imported from commit 77f965efbf5a766eb8de23486e303fa135b2e638)

zerver/lib/actions.py

@@ -1288,21 +1288,33 @@ def do_rename_stream(realm, old_name, new_name, log=True):
         to_dict_cache_key_id(message.id, True) for message in messages)
     cache_delete_many(
         to_dict_cache_key_id(message.id, False) for message in messages)
+    new_email = encode_email_address(stream)
 
     # We will tell our users to essentially
     # update stream.name = new_name where name = old_name
-    event = dict(
-        op="update",
-        type="stream",
-        property="name",
-        value=new_name,
-        name=old_name
-    )
-    send_event(event, stream_user_ids(stream))
+    # and update stream.email = new_email where name = old_name.
+    # We could optimize this by trying to send one message, but the
+    # client code really wants one property update at a time, and
+    # updating stream names is a pretty infrequent operation.
+    # More importantly, we want to key these updates by id, not name,
+    # since id is the immutable primary key, and obviously name is not.
+    data_updates = [
+        ['email_address', new_email],
+        ['name', new_name],
+    ]
+    for property, value in data_updates:
+        event = dict(
+            op="update",
+            type="stream",
+            property=property,
+            value=value,
+            name=old_name
+        )
+        send_event(event, stream_user_ids(stream))
 
     # Even though the token doesn't change, the web client needs to update the
     # email forwarding address to display the correctly-escaped new name.
-    return {"email_address": encode_email_address(stream)}
+    return {"email_address": new_email}
 
 def do_change_stream_description(realm, stream_name, new_description):
     stream = get_stream(stream_name, realm)

zerver/test_events.py

@@ -237,7 +237,8 @@ class EventsRegisterTest(AuthedTestCase):
     def test_rename_stream(self):
         realm = get_realm('zulip.com')
         stream, _ = create_stream_if_needed(realm, 'old_name')
-        new_name = 'stream with a brand new name'
+        new_name = u'stream with a brand new name'
+        self.subscribe_to_stream(self.user_profile.email, stream.name)
         self.do_test(lambda: do_rename_stream(realm, stream.name, new_name))
 
     def test_subscribe_events(self):

zerver/test_subs.py

@@ -118,7 +118,7 @@ class StreamAdminTest(AuthedTestCase):
             result = self.client.post('/json/rename_stream?old_name=stream_name1&new_name=stream_name2')
         self.assert_json_success(result)
 
-        event = events[0]['event']
+        event = events[1]['event']
         self.assertEqual(event, dict(
             op='update',
             type='stream',
@@ -126,7 +126,7 @@ class StreamAdminTest(AuthedTestCase):
             value='stream_name2',
             name='stream_name1'
         ))
-        users = events[0]['users']
+        users = events[1]['users']
         self.assertEqual(users, [user_profile.id])
 
         stream_name1_exists = Stream.objects.filter(