HTML API: Replace provenance string with is_virtual boolean on stack events

Replace the 'virtual'/'real' provenance string with a boolean is_virtual
flag. This eliminates string allocation and comparison, replacing them
with a direct boolean assignment and check.

Author: sirreal

src/wp-includes/html-api/class-wp-html-processor.php

@@ -458,8 +458,8 @@ public function __construct( $html, $use_the_static_create_methods_instead = nul
 			function ( WP_HTML_Token $token ): void {
 				$current_token         = $this->state->current_token;
 				$is_virtual            = ! isset( $current_token ) || parent::is_tag_closer();
-				$provenance            = ( ! $is_virtual && $token->node_name === $current_token->node_name ) ? 'real' : 'virtual';
-				$this->element_queue[] = new WP_HTML_Stack_Event( $token, false, $provenance );
+				$is_virtual_event      = $is_virtual || $token->node_name !== $current_token->node_name;
+				$this->element_queue[] = new WP_HTML_Stack_Event( $token, false, $is_virtual_event );
 
 				if ( $token->integration_node_type ) {
 					$this->change_parsing_namespace( 'html' );
@@ -473,8 +473,8 @@ function ( WP_HTML_Token $token ): void {
 			function ( WP_HTML_Token $token ): void {
 				$current_token         = $this->state->current_token;
 				$is_virtual            = ! isset( $current_token ) || ! parent::is_tag_closer();
-				$provenance            = ( ! $is_virtual && $token->node_name === $current_token->node_name ) ? 'real' : 'virtual';
-				$this->element_queue[] = new WP_HTML_Stack_Event( $token, true, $provenance );
+				$is_virtual_event      = $is_virtual || $token->node_name !== $current_token->node_name;
+				$this->element_queue[] = new WP_HTML_Stack_Event( $token, true, $is_virtual_event );
 
 				$adjusted_current_node = $this->get_adjusted_current_node();
 
@@ -968,10 +968,7 @@ public function is_tag_closer(): bool {
 	 * @return bool Whether the current token is virtual.
 	 */
 	private function is_virtual(): bool {
-		return (
-			isset( $this->current_element->provenance ) &&
-			'virtual' === $this->current_element->provenance
-		);
+		return isset( $this->current_element ) && $this->current_element->is_virtual;
 	}
 
 	/**

src/wp-includes/html-api/class-wp-html-stack-event.php

@@ -65,27 +65,32 @@ class WP_HTML_Stack_Event {
 	 *
 	 * @var string
 	 */
-	public $provenance;
-
 	/**
 	 * Whether this event is a pop operation.
 	 *
 	 * @var bool
 	 */
 	public $is_pop;
 
+	/**
+	 * Whether this event is for a virtual (implied) node.
+	 *
+	 * @var bool
+	 */
+	public $is_virtual;
+
 	/**
 	 * Constructor function.
 	 *
 	 * @since 6.6.0
 	 *
 	 * @param WP_HTML_Token $token      Token associated with stack event, always an opening token.
-	 * @param string        $operation  One of self::PUSH or self::POP.
-	 * @param string        $provenance "virtual" or "real".
+	 * @param bool          $is_pop     Whether this is a pop event.
+	 * @param bool          $is_virtual Whether this is a virtual event.
 	 */
-	public function __construct( WP_HTML_Token $token, bool $is_pop, string $provenance ) {
+	public function __construct( WP_HTML_Token $token, bool $is_pop, bool $is_virtual ) {
 		$this->token      = $token;
-		$this->provenance = $provenance;
 		$this->is_pop     = $is_pop;
+		$this->is_virtual = $is_virtual;
 	}
 }