Fix fatal error in Stream connector on new follower (#3372)

Author: pfefferle

.github/changelog/fix-stream-follower-fatal

@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Fix a fatal error when receiving a new follower while the Stream plugin is active.

integration/stream/class-connector.php

@@ -111,12 +111,14 @@ public function action_links( $links, $record ) {
 	/**
 	 * Callback for activitypub_handled_follow.
 	 *
-	 * @param array         $activity     The ActivityPub activity data.
-	 * @param int|null      $user_id      The local user ID, or null if not applicable.
-	 * @param mixed         $state        Status or WP_Error object indicating the result of the follow handling.
-	 * @param \WP_Post|null $context   The WP_Post object representing the remote actor/follower.
+	 * @param array              $activity The ActivityPub activity data.
+	 * @param int|int[]          $user_ids The local user ID(s) of the followed actor(s).
+	 * @param bool               $success  Whether the follow was handled successfully.
+	 * @param \WP_Post|\WP_Error $context  The remote actor/follower, or WP_Error on failure.
 	 */
-	public function callback_activitypub_handled_follow( $activity, $user_id, $state, $context ) {
+	public function callback_activitypub_handled_follow( $activity, $user_ids, $success, $context ) {
+		// The hook passes an array of user IDs; Stream's log() builds a WP_User from this, so coerce to a single integer.
+		$user_id   = (int) ( \is_array( $user_ids ) ? \reset( $user_ids ) : $user_ids );
 		$actor_url = \is_object( $context ) && ! \is_wp_error( $context ) ? $context->guid : $activity['actor'];
 
 		$this->log(

tests/phpunit/tests/integration/class-test-stream-connector.php

@@ -284,13 +284,16 @@ function ( $message, $meta, $object_id, $context_type, $action, $user_id ) use (
 				}
 			);
 
-		$stream_connector->callback_activitypub_handled_follow( $activity, self::$user_id, true, $context );
+		// The "activitypub_handled_follow" hook fires with an array of user IDs (int[]).
+		$stream_connector->callback_activitypub_handled_follow( $activity, array( self::$user_id ), true, $context );
 
 		$this->assertNotNull( $logged_data, 'Should have logged the follow event' );
 		$this->assertStringContainsString( 'New Follower: https://example.com/actor', $logged_data['message'] );
 		$this->assertEquals( 'notification', $logged_data['context_type'] );
 		$this->assertEquals( 'follow', $logged_data['action'] );
-		$this->assertEquals( self::$user_id, $logged_data['user_id'] );
+		// Stream's log() builds a WP_User from this value, so it must be a single integer, not the array.
+		$this->assertIsInt( $logged_data['user_id'], 'Stream log() must receive a single integer user ID, not an array.' );
+		$this->assertSame( self::$user_id, $logged_data['user_id'] );
 		$this->assertArrayHasKey( 'activity', $logged_data['meta'] );
 		$this->assertArrayHasKey( 'remote_actor', $logged_data['meta'] );
 	}
@@ -327,7 +330,8 @@ function ( $message, $meta ) use ( &$logged_data ) {
 				}
 			);
 
-		$stream_connector->callback_activitypub_handled_follow( $activity, self::$user_id, false, $context );
+		// The "activitypub_handled_follow" hook fires with an array of user IDs (int[]).
+		$stream_connector->callback_activitypub_handled_follow( $activity, array( self::$user_id ), false, $context );
 
 		$this->assertStringContainsString( 'New Follower: https://example.com/actor', $logged_data['message'] );
 	}