django-2.0: Don't assign directly to Many-to-Many field.

The old pattern of setting the value and then using .save() here has
been deprecated.  set() also saves the record.

zerver/lib/actions.py

@@ -3053,8 +3053,7 @@ def do_create_default_stream_group(realm: Realm, group_name: Text,
         raise JsonableError(_("Default stream group '%(group_name)s' already exists")
                             % {'group_name': group_name})
 
-    group.streams = streams
-    group.save()
+    group.streams.set(streams)
     notify_default_stream_groups(realm)
 
 def do_add_streams_to_default_stream_group(realm: Realm, group: DefaultStreamGroup,
@@ -4092,8 +4091,7 @@ def do_create_multiuse_invite_link(referred_by: UserProfile, streams: Optional[L
     realm = referred_by.realm
     invite = MultiuseInvite.objects.create(realm=realm, referred_by=referred_by)
     if streams:
-        invite.streams = streams
-        invite.save()
+        invite.streams.set(streams)
 
     return create_confirmation_link(invite, realm.host, Confirmation.MULTIUSE_INVITE)
 

zerver/management/commands/create_default_stream_groups.py

@@ -57,8 +57,7 @@ Create default stream groups which the users can choose during sign up.
         except DefaultStreamGroup.DoesNotExist:
             default_stream_group = DefaultStreamGroup.objects.create(
                 name=options["name"], realm=realm, description=options["description"])
-        default_stream_group.streams = streams
-        default_stream_group.save()
+        default_stream_group.streams.set(streams)
 
         default_stream_groups = DefaultStreamGroup.objects.all()
         for default_stream_group in default_stream_groups:

zerver/tests/test_auth_backends.py

@@ -892,8 +892,7 @@ class GoogleSubdomainLoginTest(GoogleOAuthTest):
         # Now confirm an invitation link works
         referrer = self.example_user("hamlet")
         multiuse_obj = MultiuseInvite.objects.create(realm=realm, referred_by=referrer)
-        multiuse_obj.streams = streams
-        multiuse_obj.save()
+        multiuse_obj.streams.set(streams)
         invite_link = create_confirmation_link(multiuse_obj, realm.host,
                                                Confirmation.MULTIUSE_INVITE)
 

zerver/tests/test_signup.py

@@ -1024,8 +1024,7 @@ class MultiuseInviteTest(ZulipTestCase):
         invite.save()
 
         if streams is not None:
-            invite.streams = streams
-            invite.save()
+            invite.streams.set(streams)
 
         if date_sent is None:
             date_sent = timezone_now()

zerver/views/auth.py

@@ -92,8 +92,7 @@ def maybe_send_to_registration(request: HttpRequest, email: Text, full_name: Tex
             del request.session["multiuse_object_key"]
             request.session.modified = True
             if streams_to_subscribe is not None:
-                prereg_user.streams = streams_to_subscribe
-            prereg_user.save()
+                prereg_user.streams.set(streams_to_subscribe)
 
         return redirect("".join((
             create_confirmation_link(prereg_user, request.get_host(), Confirmation.USER_REGISTRATION),

zerver/views/registration.py

@@ -304,8 +304,7 @@ def prepare_activation_url(email: str, request: HttpRequest,
     prereg_user = create_preregistration_user(email, request, realm_creation)
 
     if streams is not None:
-        prereg_user.streams = streams
-        prereg_user.save()
+        prereg_user.streams.set(streams)
 
     confirmation_type = Confirmation.USER_REGISTRATION
     if realm_creation: