Ticket #24726: 24726.3.diff

src/wp-includes/meta.php

@@ -454 +454 @@
  *              specified meta_key. This parameter has no effect if meta_key is not specified.
  * @return mixed Single metadata value, or array of values
  */
-function get_metadata($meta_type, $object_id, $meta_key = '', $single = false) {
+function get_metadata( $meta_type, $object_id, $meta_key = '', $single = false ) {
         if ( ! $meta_type || ! is_numeric( $object_id ) ) {
                 return false;
         }
@@ -482 +482 @@
          */
         $check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, $single );
         if ( null !== $check ) {
-                if ( $single && is_array( $check ) )
+                if ( $single && is_array( $check ) ) {
                         return $check[0];
-                else
+                } else {
                         return $check;
+                }
         }
 
-        $meta_cache = wp_cache_get($object_id, $meta_type . '_meta');
+        $meta_cache = wp_cache_get( $object_id, $meta_type . '_meta' );
 
-        if ( !$meta_cache ) {
+        if ( ! $meta_cache ) {
                 $meta_cache = update_meta_cache( $meta_type, array( $object_id ) );
                 $meta_cache = $meta_cache[$object_id];
         }
@@ -499 +500 @@
                 return $meta_cache;
         }
 
-        if ( isset($meta_cache[$meta_key]) ) {
-                if ( $single )
-                        return maybe_unserialize( $meta_cache[$meta_key][0] );
-                else
-                        return array_map('maybe_unserialize', $meta_cache[$meta_key]);
+        if ( isset( $meta_cache[ $meta_key ] ) ) {
+                if ( $single ) {
+                        $meta_value = maybe_unserialize( $meta_cache[ $meta_key ][0] );
+                } else {
+                        $meta_value = array_map( 'maybe_unserialize', $meta_cache[ $meta_key ] );
+                }
+        } else {
+                if ( $single ) {
+                        $meta_value = '';
+                } else {
+                        $meta_value = array();
+                }
         }
-
-        if ($single)
-                return '';
-        else
-                return array();
+        /**
+         * Filter whether to retrieve metadata of a specific type.
+         *
+         * The dynamic portion of the hook, `$meta_type`, refers to the meta
+         * object type (comment, post, or user) and `$meta_key` refers to Meta key.
+         * Returning a non-null value will effectively short-circuit the function.
+         *
+         * @since 4.3.0
+         *
+         * @param null|array|string $value     The value get_metadata() should
+         *                                     return - a single metadata value,
+         *                                     or an array of values.
+         * @param int               $object_id Object ID.
+         * @param string|array      $single    Meta value, or an array of values.
+         */
+        return apply_filters( "get_{$meta_type}_metadata-{$meta_key}", $meta_value, $object_id, $single );
 }
 
 /**