Ticket #52787: 52787.2.diff

src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php

@@ -232 +232 @@
                         );
                 }
 
+                if ( null === get_metadata_raw( $meta_type,  $object_id, wp_slash( $meta_key ) ) ) {
+                        return true;
+                }
+
                 if ( ! delete_metadata( $meta_type, $object_id, wp_slash( $meta_key ) ) ) {
                         return new WP_Error(
                                 'rest_meta_database_error',

tests/phpunit/tests/rest-api/rest-post-meta-fields.php

@@ -1052 +1052 @@
                 $this->assertEmpty( $meta );
         }
 
+        /**
+         * Ensure deleting non-existant meta data behaves gracefully.
+         *
+         * @ticket 52787
+         * @dataProvider data_delete_does_not_trigger_error_if_no_meta_values
+         *
+         * @param array|null $delete_value Value used to delete meta data.
+         */
+        public function test_delete_does_not_trigger_error_if_no_meta_values( $delete_value ) {
+                $this->grant_write_permission();
+
+                $data    = array(
+                        'meta' => array(
+                                'test_multi' => $delete_value,
+                        ),
+                );
+                $request = new WP_REST_Request( 'POST', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+                $request->set_body_params( $data );
+
+                $response = rest_get_server()->dispatch( $request );
+
+                $this->assertSame( 200, $response->get_status() );
+        }
+
+        /**
+         * Data provider for test_delete_does_not_trigger_error_if_no_meta_values().
+         *
+         * @return array[] Array of test parameters.
+         */
+        public function data_delete_does_not_trigger_error_if_no_meta_values() {
+                return array(
+                        array( array() ),
+                        array( null ),
+                );
+        }
+
         public function test_remove_multi_value_db_error() {
                 add_post_meta( self::$post_id, 'test_multi', 'val1' );
                 $values = get_post_meta( self::$post_id, 'test_multi', false );