Port WordPress/wordpress-develop#6257

lib/compat/wordpress-6.5/interactivity-api/class-wp-interactivity-api.php

@@ -572,15 +572,21 @@ private function data_wp_bind_processor( WP_Interactivity_API_Directives_Process
 					$attribute_value = $p->get_attribute( $attribute_name );
 					$result          = $this->evaluate( $attribute_value, end( $namespace_stack ), end( $context_stack ) );
 
-					if ( null !== $result && ( false !== $result || '-' === $bound_attribute[4] ) ) {
+					if ( null !== $result && (
+						false !== $result ||
+						( strlen( $bound_attribute ) > 5 && '-' === $bound_attribute[4] )
+					) ) {
 						/*
 						 * If the result of the evaluation is a boolean and the attribute is
 						 * `aria-` or `data-, convert it to a string "true" or "false". It
 						 * follows the exact same logic as Preact because it needs to
 						 * replicate what Preact will later do in the client:
 						 * https://github.com/preactjs/preact/blob/ea49f7a0f9d1ff2c98c0bdd66aa0cbc583055246/src/diff/props.js#L131C24-L136
 						 */
-						if ( is_bool( $result ) && '-' === $bound_attribute[4] ) {
+						if (
+							is_bool( $result ) &&
+							( strlen( $bound_attribute ) > 5 && '-' === $bound_attribute[4] )
+						) {
 							$result = $result ? 'true' : 'false';
 						}
 						$p->set_attribute( $bound_attribute, $result );