Ticket #48061: 48061.diff

src/wp-includes/class-wp-query.php

@@ -1695 +1695 @@
                 $this->is_404 = true;
 
                 $this->is_feed = $is_feed;
+
+                /**
+                 * Fires after a 404 is triggered.
+                 *
+                 * @since x.x.x
+                 *
+                 * @param WP_Query $this The WP_Query instance (passed by reference).
+                 */
+                do_action_ref_array( 'set_404', array( $this ) );
         }
 
         /**