PHP 7.2 Incompatibility - count(): Parameter must be an array or an object that implements Countable in krumo::_object

Yes, count() expects an array. I don't think the Countable interface is a consideration here.

I also found another instance of count() potentially getting a non-array, as well as an undefined index, both outside of krumo, but related to dpm() et al.

After giving this some more thought, here's an improved patch.

Re-rolled after committing #2855666: Make Krumo compatible with XSS injection protection to drupal_set_message().

So this has added is_array(), I'm wondering if instead we should be duplicating the code from merits_krumo() and using (is_object($input) || is_array($input)) instead?

Given is_object($input) == TRUE, how likely is it that $input implements Countable? And even if it does, what would this give to us?

Granted, the patch is on the efficient side rather than on the sophisticated side, but do you see any relevant use case for change?

another error similar to the latest version drupal 7.9+ php 7.4-fpm + nginx and memcached server:

Warning: count(): Parameter must be an array or an object that implements Countable in _object() (line 1111 of /var/www/mysite.com/web/sites/all/modules/devel/krumo/class.krumo.php).

this error is always present in the logs even though everything is updated with the composer, any suggestion is welcome

1111  <?php if (count($data)) { 
1112   krumo::_vars($data); 
1113    } ?>