Bolt\Config::isCacheValid PHP Method

    private function isCacheValid()
    {
        if (!$this->cacheFile->exists()) {
            return false;
        }
        $cachedConfigTimestamp = $this->cacheFile->getTimestamp();
        /** @var \Bolt\Filesystem\Filesystem $configFs */
        $configFs = $this->app['filesystem.config'];
        $configFiles = ['config.yml', 'config_local.yml', 'contenttypes.yml', 'extensions.yml', 'menu.yml', 'permissions.yml', 'routing.yml', 'taxonomy.yml'];
        foreach ($configFiles as $configFile) {
            $timestamp = $configFs->has($configFile) ? $configFs->get($configFile)->getTimestamp() : 0;
            if ($timestamp > $cachedConfigTimestamp) {
                // The configuration file timestamp is *newer* than the cache file's … invalidate!
                $this->invalidateCache();
                return false;
            }
        }
        return true;
    }