Blocks: Add automatic RTL handlind for block styles registered from m…

…etadata

Related Gutenberg issue: WordPress/gutenberg#28274

With this change it is going to be possible to use the same pattern that wp_style_add_data uses for RTL handling. If the block style file with "-rtl.css" is included in addition to the regular style referenced in "block.json" file then it is going to be automatically registered.

Props swisspidy, aristath.
See #52301.


Built from https://develop.svn.wordpress.org/trunk@49982


git-svn-id: http://core.svn.wordpress.org/trunk@49683 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/blocks.php

@@ -169,12 +169,17 @@ function register_block_style_handle( $metadata, $field_name ) {
 
 	$style_handle = generate_block_asset_handle( $metadata['name'], $field_name );
 	$block_dir    = dirname( $metadata['file'] );
+	$style_file   = realpath( "$block_dir/$style_path" );
 	$result       = wp_register_style(
 		$style_handle,
 		plugins_url( $style_path, $metadata['file'] ),
 		array(),
-		filemtime( realpath( "$block_dir/$style_path" ) )
+		filemtime( $style_file )
 	);
+	if ( file_exists( str_replace( '.css', '-rtl.css', $style_file ) ) ) {
+		wp_style_add_data( $style_handle, 'rtl', 'replace' );
+	}
+
 	return $result ? $style_handle : false;
 }
 

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.7-alpha-49981';
+$wp_version = '5.7-alpha-49982';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.