Php artisan not working (laravel 5.1)

Suddenly when i type php artisan or any artisan command i seen this message

[ErrorException]
Trying to get property of non-object

I tried the following

1- php artisan clear-compiled

2- To delete vendor directory and use composer install Or composer update

3- clone a standard Laravel app and put my files app dir and my config and use composer commands but with step the error has changed to be

[ErrorException]
Trying to get property of non-object

Script php artisan clear-compiled handling the post-install-cmd event returned with an error

[RuntimeException]
Error Output:

Any Suggestions ?

Thanks

via Chebli Mohamed