Schema bugfixes (#356)

* Bugfix: Markdown type uses json_path type

* Improvement: Allow numeric values to be stringified in validation errors

* Bugfix: Require button_text and id to be non-empty

* Improve tests

inc/Validation/Types.php

@@ -97,7 +97,7 @@ public static function json_path(): array {
 	}
 
 	public static function markdown(): array {
-		return self::generate_primitive_type( 'json_path' );
+		return self::generate_primitive_type( 'markdown' );
 	}
 
 	public static function url(): array {

inc/Validation/Validator.php

@@ -196,13 +196,15 @@ private function check_primitive_type( string $type_name, mixed $value ): bool {
 			case 'email_address':
 				return false !== is_email( $value );
 
-			case 'button_text':
 			case 'html':
-			case 'id':
 			case 'image_alt':
 			case 'markdown':
 				return is_string( $value );
 
+			case 'button_text':
+			case 'id':
+				return is_string( $value ) && ! empty( $value );
+
 			case 'json_path':
 				return is_string( $value ) && str_starts_with( $value, '$' );
 
@@ -229,7 +231,7 @@ public static function check_iterable_object( mixed $value ): bool {
 	}
 
 	private function create_error( string $message, mixed $value, ?WP_Error $child_error = null ): WP_Error {
-		$serialized_value = is_string( $value ) ? $value : wp_json_encode( $value );
+		$serialized_value = is_string( $value ) || is_numeric( $value ) ? strval( $value ) : wp_json_encode( $value );
 		$message = sprintf( '%s: %s', esc_html( $message ), $serialized_value );
 		return new WP_Error( 'invalid_type', $message, [ 'child' => $child_error ] );
 	}