Theme JSON: remove redundant styles check and relocate $selectors ass…

…ignment.

In `WP_Theme_JSON::get_block_nodes()`, remove redundant check for `$theme_json['styles']`, which means `WP_Theme_JSON::get_blocks_metadata()` is only called if necessary.

Also skip unnecessary `$selector` assignment if only nodes are to be returned.

Props ramonopoly, mukesh27.  
Fixes #62234.




git-svn-id: https://develop.svn.wordpress.org/trunk@59262 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-theme-json.php

@@ -2707,20 +2707,20 @@ private static function update_separator_declarations( $declarations ) {
 	 * @return array The block nodes in theme.json.
 	 */
 	private static function get_block_nodes( $theme_json, $selectors = array(), $options = array() ) {
-		$selectors = empty( $selectors ) ? static::get_blocks_metadata() : $selectors;
-		$nodes     = array();
-		if ( ! isset( $theme_json['styles'] ) ) {
-			return $nodes;
-		}
+		$nodes = array();
 
-		// Blocks.
 		if ( ! isset( $theme_json['styles']['blocks'] ) ) {
 			return $nodes;
 		}
 
 		$include_variations      = $options['include_block_style_variations'] ?? false;
 		$include_node_paths_only = $options['include_node_paths_only'] ?? false;
 
+		// If only node paths are to be returned, skip selector assignment.
+		if ( ! $include_node_paths_only ) {
+			$selectors = empty( $selectors ) ? static::get_blocks_metadata() : $selectors;
+		}
+
 		foreach ( $theme_json['styles']['blocks'] as $name => $node ) {
 			$node_path = array( 'styles', 'blocks', $name );
 			if ( $include_node_paths_only ) {