composer: count() Parameter must be an array or an object that implements Countable

При установке модуля composer выдает вот такое предупреждение:

[ErrorException]
count(): Parameter must be an array or an object that implements Countable

Fatal error: Uncaught Symfony\Component\Process\Exception\RuntimeException: Unable to kill the 
process in phar://D:/OSPanel/modules/php/PHP-7.2- 
x64/composer.phar/vendor/symfony/process/Process.php:779
Stack trace:
#0 phar://D:/OSPanel/modules/php/PHP-7.2-x64/composer.phar/vendor/symfony/process/Process.php(173): 
Symfony\Component\Process\Process->stop()
#1 [internal function]: Symfony\Component\Process\Process->__destruct()
#2 {main}
thrown in phar://D:/OSPanel/modules/php/PHP-7.2-x64/composer.phar/vendor/symfony/process/Process.php 
on line 779

откатывал версию php - не помогает. как исправить?