PHP 8.1 compatibility - do not attempt to count() NULL

[Detsieber]

Although donrec in general is working fine with PHP 8.0/8.1, in certain conditions we get a wsod.

This is caused by the php function count, that behaves differently with php 8:
https://www.php.net/manual/en/function.count.php

count() will now throw TypeError on invalid countable types passed to the value parameter.

I have prepared a pull request.

[jensschuppe]

If I get that correctly, you're talking about those two occurences of count() without a guard of the variable being countable:

de.systopia.donrec/CRM/Donrec/Form/Task/ContributeTask.php

Line 107 in d6ced5d

CRM_Utils_System::url('civicrm/donrec/task', 'conflict=1' . '&sid=' . $result['snapshot']->getId() . '&ccount=' . count($this->_contactIds)));

and

de.systopia.donrec/CRM/Donrec/Form/Task/ContributeTask.php

Line 114 in d6ced5d

CRM_Utils_System::url('civicrm/donrec/task', 'sid=' . $result['snapshot']->getId() . '&ccount=' . count($this->_contactIds))

and possibly more ...

… while I'm not sure what would cause $this->_contactIds not be an array. But the easiest solution would be to just call $this->getContactIDs() instead of direct access of $this->_contactIds, as the getter does a null-coalesce check with ?? [], which should be enough as the variable will be either an array or NULL.

Your PR, however, is filed against your fork, not the origin repo. I created #180 instead which should fix the issue for all occurences - would you be able to review that one, @Detsieber?