Inline was_mutated flag on native parser node hot path (#390)

## Summary

Drop the `was_mutated()` getter from `WP_MySQL_Native_Parser_Node` and
read the property directly. The flag is checked on every read of a
native-backed node, so a method call per access shows up on full-tree
traversals.

The naming still reads at the call sites (`if ( \$this->was_mutated )`),
so we don't lose anything by inlining.

Author: adamziel

packages/mysql-on-sqlite/src/mysql/native/class-wp-mysql-native-parser-node.php

@@ -38,136 +38,132 @@ public function merge_fragment( $node ) {
 
 	/** @inheritDoc */
 	public function has_child(): bool {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::has_child();
 		}
 		return wp_sqlite_mysql_native_ast_has_child( $this->native_ast, $this->native_node_index );
 	}
 
 	/** @inheritDoc */
 	public function has_child_node( ?string $rule_name = null ): bool {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::has_child_node( $rule_name );
 		}
 		return wp_sqlite_mysql_native_ast_has_child_node( $this->native_ast, $this->native_node_index, $rule_name );
 	}
 
 	/** @inheritDoc */
 	public function has_child_token( ?int $token_id = null ): bool {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::has_child_token( $token_id );
 		}
 		return wp_sqlite_mysql_native_ast_has_child_token( $this->native_ast, $this->native_node_index, $token_id );
 	}
 
 	/** @inheritDoc */
 	public function get_first_child() {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_first_child();
 		}
 		return wp_sqlite_mysql_native_ast_get_first_child( $this->native_ast, $this->native_node_index );
 	}
 
 	/** @inheritDoc */
 	public function get_first_child_node( ?string $rule_name = null ): ?WP_Parser_Node {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_first_child_node( $rule_name );
 		}
 		return wp_sqlite_mysql_native_ast_get_first_child_node( $this->native_ast, $this->native_node_index, $rule_name );
 	}
 
 	/** @inheritDoc */
 	public function get_first_child_token( ?int $token_id = null ): ?WP_Parser_Token {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_first_child_token( $token_id );
 		}
 		return wp_sqlite_mysql_native_ast_get_first_child_token( $this->native_ast, $this->native_node_index, $token_id );
 	}
 
 	/** @inheritDoc */
 	public function get_first_descendant_node( ?string $rule_name = null ): ?WP_Parser_Node {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_first_descendant_node( $rule_name );
 		}
 		return wp_sqlite_mysql_native_ast_get_first_descendant_node( $this->native_ast, $this->native_node_index, $rule_name );
 	}
 
 	/** @inheritDoc */
 	public function get_first_descendant_token( ?int $token_id = null ): ?WP_Parser_Token {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_first_descendant_token( $token_id );
 		}
 		return wp_sqlite_mysql_native_ast_get_first_descendant_token( $this->native_ast, $this->native_node_index, $token_id );
 	}
 
 	/** @inheritDoc */
 	public function get_children(): array {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_children();
 		}
 		return wp_sqlite_mysql_native_ast_get_children( $this->native_ast, $this->native_node_index );
 	}
 
 	/** @inheritDoc */
 	public function get_child_nodes( ?string $rule_name = null ): array {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_child_nodes( $rule_name );
 		}
 		return wp_sqlite_mysql_native_ast_get_child_nodes( $this->native_ast, $this->native_node_index, $rule_name );
 	}
 
 	/** @inheritDoc */
 	public function get_child_tokens( ?int $token_id = null ): array {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_child_tokens( $token_id );
 		}
 		return wp_sqlite_mysql_native_ast_get_child_tokens( $this->native_ast, $this->native_node_index, $token_id );
 	}
 
 	/** @inheritDoc */
 	public function get_descendants(): array {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_descendants();
 		}
 		return wp_sqlite_mysql_native_ast_get_descendants( $this->native_ast, $this->native_node_index );
 	}
 
 	/** @inheritDoc */
 	public function get_descendant_nodes( ?string $rule_name = null ): array {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_descendant_nodes( $rule_name );
 		}
 		return wp_sqlite_mysql_native_ast_get_descendant_nodes( $this->native_ast, $this->native_node_index, $rule_name );
 	}
 
 	/** @inheritDoc */
 	public function get_descendant_tokens( ?int $token_id = null ): array {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_descendant_tokens( $token_id );
 		}
 		return wp_sqlite_mysql_native_ast_get_descendant_tokens( $this->native_ast, $this->native_node_index, $token_id );
 	}
 
 	/** @inheritDoc */
 	public function get_start(): int {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_start();
 		}
 		return wp_sqlite_mysql_native_ast_get_start( $this->native_ast, $this->native_node_index );
 	}
 
 	/** @inheritDoc */
 	public function get_length(): int {
-		if ( $this->was_mutated() ) {
+		if ( $this->was_mutated ) {
 			return parent::get_length();
 		}
 		return wp_sqlite_mysql_native_ast_get_length( $this->native_ast, $this->native_node_index );
 	}
 
-	private function was_mutated(): bool {
-		return $this->was_mutated;
-	}
-
 	private function materialize_native_children(): void {
 		if ( $this->was_mutated ) {
 			return;