internal_send_stream_message: Support accepting a Stream object.

If the caller has access to a Stream object, it is wasteful to
query a database for a stream by ID or name. In addition, not
having to go through stream names eliminates various classes of
possible bugs involved with re-fetching the Stream object by name.

zerver/lib/actions.py

@@ -2400,10 +2400,18 @@ def internal_send_private_message(realm: Realm,
         return
     do_send_messages([message])
 
-def internal_send_stream_message(realm: Realm, sender: UserProfile, stream_name: str,
-                                 topic: str, content: str) -> None:
-    message = internal_prep_stream_message(realm, sender, topic,
-                                           content, stream_name=stream_name)
+def internal_send_stream_message(
+        realm: Realm, sender: UserProfile,
+        topic: str, content: str,
+        stream_name: Optional[str]=None,
+        stream: Optional[Stream]=None
+) -> None:
+    message = internal_prep_stream_message(
+        realm, sender, topic,
+        content, stream_name=stream_name,
+        stream=stream
+    )
+
     if message is None:
         return
     do_send_messages([message])
@@ -3443,11 +3451,11 @@ def do_rename_stream(stream: Stream,
     internal_send_stream_message(
         stream.realm,
         sender,
-        new_name,
         "welcome",
         "_@**%s|%d** renamed stream **%s** to **%s**" % (user_profile.full_name,
                                                          user_profile.id,
-                                                         old_name, new_name)
+                                                         old_name, new_name),
+        stream=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.

zerver/lib/bot_lib.py

@@ -71,8 +71,11 @@ class EmbeddedBotHandler:
             self._rate_limit.show_error_and_exit()
 
         if message['type'] == 'stream':
-            internal_send_stream_message(self.user_profile.realm, self.user_profile, message['to'],
-                                         message['topic'], message['content'])
+            internal_send_stream_message(
+                self.user_profile.realm, self.user_profile,
+                message['topic'], message['content'],
+                stream_name=message['to']
+            )
             return
 
         assert message['type'] == 'private'

zerver/lib/email_mirror.py

@@ -21,7 +21,7 @@ from zerver.lib.utils import generate_random_token
 from zerver.lib.send_email import FromAddress
 from zerver.models import Stream, Recipient, \
     get_user_profile_by_id, get_display_recipient, get_personal_recipient, \
-    Message, Realm, UserProfile, get_system_bot, get_user
+    Message, Realm, UserProfile, get_system_bot, get_user, get_stream_by_id_in_realm
 
 logger = logging.getLogger(__name__)
 
@@ -154,22 +154,25 @@ def send_to_missed_message_address(address: str, message: message.Message) -> No
 
     user_profile = get_user_profile_by_id(user_profile_id)
     recipient = Recipient.objects.get(id=recipient_id)
-    display_recipient = get_display_recipient(recipient)
 
     body = construct_zulip_body(message, user_profile.realm)
 
     if recipient.type == Recipient.STREAM:
-        assert isinstance(display_recipient, str)
-        recipient_str = display_recipient
-        internal_send_stream_message(user_profile.realm, user_profile, recipient_str,
-                                     subject_b.decode('utf-8'), body)
+        stream = get_stream_by_id_in_realm(recipient.type_id, user_profile.realm)
+        internal_send_stream_message(
+            user_profile.realm, user_profile,
+            subject_b.decode('utf-8'), body,
+            stream=stream
+        )
     elif recipient.type == Recipient.PERSONAL:
+        display_recipient = get_display_recipient(recipient)
         assert not isinstance(display_recipient, str)
         recipient_str = display_recipient[0]['email']
         recipient_user = get_user(recipient_str, user_profile.realm)
         internal_send_private_message(user_profile.realm, user_profile,
                                       recipient_user, body)
     elif recipient.type == Recipient.HUDDLE:
+        display_recipient = get_display_recipient(recipient)
         assert not isinstance(display_recipient, str)
         emails = [user_dict['email'] for user_dict in display_recipient]
         recipient_str = ', '.join(emails)

zerver/tests/test_messages.py

@@ -508,7 +508,7 @@ class InternalPrepTest(ZulipTestCase):
         cordelia = self.example_user('cordelia')
         hamlet = self.example_user('hamlet')
         othello = self.example_user('othello')
-        stream_name = 'Verona'
+        stream = get_stream('Verona', realm)
 
         with mock.patch('logging.exception') as m:
             internal_send_private_message(
@@ -536,9 +536,9 @@ class InternalPrepTest(ZulipTestCase):
             internal_send_stream_message(
                 realm=realm,
                 sender=cordelia,
-                stream_name=stream_name,
                 topic='whatever',
                 content=bad_content,
+                stream=stream
             )
 
         arg = m.call_args_list[0][0][0]
@@ -549,7 +549,7 @@ class InternalPrepTest(ZulipTestCase):
                 realm=realm,
                 sender_email=settings.ERROR_BOT,
                 recipient_type_name='stream',
-                recipients=stream_name,
+                recipients=stream.name,
                 topic_name='whatever',
                 content=bad_content,
             )