In Symfony 2.5 they introduced the option to have a Symfony3 directory structure with which the current plugin does not work.
The new directory structure contains the console command inside the bin/ folder rather than app/.
app/console by default (if you create a new Symfony project via composer create-project or by downloading it from symfony.com) is not executable. Therefore I get the following error:
sf2 _symfony2_get_command_list:1: permission denied: app/console
_symfony2_get_command_list:1: permission denied: app/console
_symfony2_get_command_list:1: permission denied: app/console
To make command completion work without changing app/console you just have to let php run it.