Application.php

<?php

// Illuminate\Foundation\Application

public function configurationIsCached()
{
    return file_exists($this->getCachedConfigPath());
}

public function getCachedConfigPath()
{
    return $this->normalizeCachePath('APP_CONFIG_CACHE', 'cache/config.php');
}

protected function normalizeCachePath($key, $default)
{
    if (is_null($env = Env::get($key))) {
        return $this->bootstrapPath($default);
    }

    return Str::startsWith($env, '/')
            ? $env
            : $this->basePath($env);
}

// Deal with your bootstrap path
public function bootstrapPath($path = '')
{
    return $this->basePath.DIRECTORY_SEPARATOR.'bootstrap'.($path ? DIRECTORY_SEPARATOR.$path : $path);
}

// Deal with your base path
public function basePath($path = '')
{
    return $this->basePath.($path ? DIRECTORY_SEPARATOR.$path : $path);
}