symfony: Cache:clear fails on 2.6

Everyone who override the getCacheDir() in app/AppKernel.php like

    public function getCacheDir()
    {
        return $this->rootDir.'/../var/cache/'.$this->environment;
    }

may avoid this issue by using realpath()

    public function getCacheDir()
    {
        return realpath($this->rootDir.'/../var/cache).'/'.$this->environment;
    }

or have a look at PR #12928, which does basically the same, but for all paths in the generated container.

I don’t know if the getCacheDir is overridden by default, for setups were the Symfony 3.0 structure was chosen when installing via composer. If not, you can try to override it nonetheless.

Looks like it happens when using a custom cache location. Maybe something to do with #12784?

Steps to reproduce:

1. Install a new app: symfony new myapp

2. cd myapp

3. Add to app/AppKernel.php:

   public function getCacheDir()
   {
       return $this->rootDir.'/../var/cache/'.$this->environment;
   }
   
   public function getLogDir()
   {
       return $this->rootDir.'/../var/logs';
   }
   

4. app/console ca:cl (works)

5. app/console ca:cl (error)

[RuntimeException]                                                            
  Unable to write in the ".../myapp/app/../var/cache/de_" directory