path_join: narrow return type

[IanDelMar]

path_join():

/**
 * @param string $base Base path.
 * @param string $path Path relative to $base.
 * @return string The path with the base or absolute path.
 */
function path_join( $base, $path ) {
	if ( path_is_absolute( $path ) ) {
		return $path;
	}

	return rtrim( $base, '/' ) . '/' . $path;
}

Neither '' nor '0' is an absolute path. Therefore, path_join() returns a non-falsy-string.

[szepeviktor]

You do much better than the oracle.