Spacing presets: Add check for 0 spacing steps (#43105)

lib/compat/wordpress-6.1/class-wp-theme-json-6-1.php

@@ -1176,7 +1176,6 @@ public function set_spacing_sizes() {
 		$spacing_scale = _wp_array_get( $this->theme_json, array( 'settings', 'spacing', 'spacingScale' ), array() );
 
 		if ( ! is_numeric( $spacing_scale['steps'] )
-			|| ! $spacing_scale['steps'] > 0
 			|| ! isset( $spacing_scale['mediumStep'] )
 			|| ! isset( $spacing_scale['unit'] )
 			|| ! isset( $spacing_scale['operator'] )
@@ -1191,6 +1190,11 @@ public function set_spacing_sizes() {
 			return null;
 		}
 
+		// If theme authors want to prevent the generation of the core spacing scale they can set their theme.json spacingScale.steps to 0.
+		if ( 0 === $spacing_scale['steps'] ) {
+			return null;
+		}
+
 		$unit            = '%' === $spacing_scale['unit'] ? '%' : sanitize_title( $spacing_scale['unit'] );
 		$current_step    = $spacing_scale['mediumStep'];
 		$steps_mid_point = round( ( ( $spacing_scale['steps'] ) / 2 ), 0 );