Since PHP 7.4 introduces type-hinting for properties, it is particularly important to provide valid values for all properties, so that all properties have values that match their declared types.
A property that has never been assigned doesn't have a null value, but it is on an undefined state, which will never match any declared type. undefined !== null.
so we can not check the status of a property in this way:
!$this->update
punyflash
commented
2 years ago
Since PHP 7.4 introduces type-hinting for properties, it is particularly important to provide valid values for all properties, so that all properties have values that match their declared types. A property that has never been assigned doesn't have a null value, but it is on an undefined state, which will never match any declared type. undefined !== null. so we can not check the status of a property in this way: !$this->update