}
$dao->find(TRUE);
- if (isset($metadata['on_change']) && !($value == 0 && ($dao->value === NULL || unserialize($dao->value) == 0))) {
+ // Call 'on_change' listeners. It would be nice to only fire when there's
+ // a genuine change in the data. However, PHP developers have mixed
+ // expectations about whether 0, '0', '', NULL, and FALSE represent the same
+ // value, so there's no universal way to determine if a change is genuine.
+ if (isset($metadata['on_change'])) {
foreach ($metadata['on_change'] as $callback) {
call_user_func(
\Civi\Core\Resolver::singleton()->get($callback),