Only send stream update events to clients that need them

Stream name and descriptions updates were being sent to all of the
active users on a realm. They are now only send to users who would have
information about that stream.

(imported from commit 2621ee8029f7356bf44ec493d7b5361bd546a8f5)

zerver/lib/actions.py

@@ -86,6 +86,14 @@ def log_event(event):
 def active_user_ids(realm):
     return [userdict['id'] for userdict in get_active_user_dicts_in_realm(realm)]
 
+def stream_user_ids(stream):
+    subscriptions = Subscription.objects.filter(recipient__type=Recipient.STREAM,
+                                                recipient__type_id=stream.id)
+    if stream.invite_only:
+        subscriptions = subscriptions.filter(active=True)
+
+    return [sub['user_profile_id'] for sub in subscriptions.values('user_profile_id')]
+
 def notify_created_user(user_profile):
     event = dict(type="realm_user", op="add",
                  person=dict(email=user_profile.email,
@@ -1246,7 +1254,7 @@ def do_rename_stream(realm, old_name, new_name, log=True):
         value=new_name,
         name=old_name
     )
-    send_event(event, active_user_ids(realm))
+    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.
@@ -1260,7 +1268,7 @@ def do_change_stream_description(realm, stream_name, new_description):
     event = dict(type='stream', op='update',
                  property='description', name=stream_name,
                  value=new_description)
-    send_event(event, active_user_ids(realm))
+    send_event(event, stream_user_ids(stream))
     return {}
 
 def do_create_realm(domain, name, restricted_to_domain=True):

zerver/tests.py

@@ -391,6 +391,8 @@ class StreamAdminTest(AuthedTestCase):
             value='stream_name2',
             name='stream_name1'
         ))
+        users = events[0]['users']
+        self.assertEqual(users, [user_profile.id])
 
         stream_name1_exists = Stream.objects.filter(
             name='stream_name1',
@@ -422,10 +424,23 @@ class StreamAdminTest(AuthedTestCase):
         do_add_subscription(user_profile, stream, no_log=True)
         do_change_is_admin(user_profile, True)
 
-        result = self.client_patch('/json/streams/stream_name1',
+        events = []
-                                  {'description': ujson.dumps('Test description')})
+        with tornado_redirected_to_list(events):
+            result = self.client_patch('/json/streams/stream_name1',
+                                      {'description': ujson.dumps('Test description')})
         self.assert_json_success(result)
 
+        event = events[0]['event']
+        self.assertEqual(event, dict(
+            op='update',
+            type='stream',
+            property='description',
+            value='Test description',
+            name='stream_name1'
+        ))
+        users = events[0]['users']
+        self.assertEqual(users, [user_profile.id])
+
         stream = Stream.objects.get(
             name='stream_name1',
             realm=realm,
@@ -436,6 +451,7 @@ class StreamAdminTest(AuthedTestCase):
         email = 'hamlet@zulip.com'
         self.login(email)
         user_profile = get_user_profile_by_email(email)
+
         realm = user_profile.realm
         stream, _ = create_stream_if_needed(realm, 'stream_name1')
         do_add_subscription(user_profile, stream, no_log=True)