rabbit_core_ff: Remove no-op migration functions

There is no need to add a migration function which does nothing.
Ignoring the third argument and always returning `ok` is incorrect
anyway.

deps/rabbit/src/rabbit_core_ff.erl

@@ -7,21 +7,17 @@
 
 -module(rabbit_core_ff).
 
--export([classic_mirrored_queue_version_migration/3,
-         quorum_queue_migration/3,
-         stream_queue_migration/3,
+-export([quorum_queue_migration/3,
          implicit_default_bindings_migration/3,
          virtual_host_metadata_migration/3,
          maintenance_mode_status_migration/3,
          user_limits_migration/3,
-         stream_single_active_consumer_migration/3,
          direct_exchange_routing_v2_migration/3]).
 
 -rabbit_feature_flag(
    {classic_mirrored_queue_version,
     #{desc          => "Support setting version for classic mirrored queues",
-      stability     => stable,
-      migration_fun => {?MODULE, classic_mirrored_queue_version_migration}
+      stability     => stable
      }}).
 
 -rabbit_feature_flag(
@@ -37,8 +33,7 @@
     #{desc          => "Support queues of type `stream`",
       doc_url       => "https://www.rabbitmq.com/stream.html",
       stability     => stable,
-      depends_on    => [quorum_queue],
-      migration_fun => {?MODULE, stream_queue_migration}
+      depends_on    => [quorum_queue]
      }}).
 
 -rabbit_feature_flag(
@@ -75,8 +70,7 @@
     #{desc          => "Single active consumer for streams",
       doc_url       => "https://www.rabbitmq.com/stream.html",
       stability     => stable,
-      depends_on    => [stream_queue],
-      migration_fun => {?MODULE, stream_single_active_consumer_migration}
+      depends_on    => [stream_queue]
      }}).
 
 -rabbit_feature_flag(
@@ -93,9 +87,6 @@
        stability     => stable
      }}).
 
-classic_mirrored_queue_version_migration(_FeatureName, _FeatureProps, _Enable) ->
-    ok.
-
 %% -------------------------------------------------------------------
 %% Quorum queues.
 %% -------------------------------------------------------------------
@@ -115,9 +106,6 @@ quorum_queue_migration(_FeatureName, _FeatureProps, is_enabled) ->
     mnesia:table_info(rabbit_queue, attributes) =:= Fields andalso
     mnesia:table_info(rabbit_durable_queue, attributes) =:= Fields.
 
-stream_queue_migration(_FeatureName, _FeatureProps, _Enable) ->
-    ok.
-
 migrate_to_amqqueue_with_type(FeatureName, [Table | Rest], Fields) ->
     rabbit_log_feature_flags:info(
       "Feature flag `~s`:   migrating Mnesia table ~s...",
@@ -214,15 +202,6 @@ user_limits_migration(_FeatureName, _FeatureProps, enable) ->
 user_limits_migration(_FeatureName, _FeatureProps, is_enabled) ->
     mnesia:table_info(rabbit_user, attributes) =:= internal_user:fields(internal_user_v2).
 
-%% -------------------------------------------------------------------
-%% Stream single active consumer.
-%% -------------------------------------------------------------------
-
-stream_single_active_consumer_migration(_FeatureName, _FeatureProps, enable) ->
-    ok;
-stream_single_active_consumer_migration(_FeatureName, _FeatureProps, is_enabled) ->
-    undefined.
-
 %% -------------------------------------------------------------------
 %% Direct exchange routing v2.
 %% -------------------------------------------------------------------