Layout: Skip outputting base layout rules that reference content or wide sizes if no layout sizes exist (#60489)

* Layout: Skip outputting base layout rules that reference content or wide sizes if no content or wide sizes exist

* Update tests

Author: andrewserong

lib/class-wp-theme-json-gutenberg.php

@@ -1614,6 +1614,16 @@ protected function get_layout_styles( $block_metadata ) {
 							! empty( $base_style_rule['rules'] )
 						) {
 							foreach ( $base_style_rule['rules'] as $css_property => $css_value ) {
+								// Skip rules that reference content size or wide size if they are not defined in the theme.json.
+								if (
+									is_string( $css_value ) &&
+									( str_contains( $css_value, '--global--content-size' ) || str_contains( $css_value, '--global--wide-size' ) ) &&
+									! isset( $this->theme_json['settings']['layout']['contentSize'] ) &&
+									! isset( $this->theme_json['settings']['layout']['wideSize'] )
+								) {
+									continue;
+								}
+
 								if ( static::is_safe_css_declaration( $css_property, $css_value ) ) {
 									$declarations[] = array(
 										'name'  => $css_property,