Class used with instanceof is not of valid type PHP-E1009
Bug risk
Major
A class that you are trying to check against using instanceof keyword is not of valid class object type. This will result in fatal runtime error.
This can happen because of human errors, and it is recommended to make sure that:
- A class you are trying to check against exists.
- There's no typo in the class or interface name.
self/parentis not being used outside of a class scope.
Bad practice
class ObjectChecker
{
public function isInstanceOfBaseGreet($object): bool
{
if ($object instanceof BaseGreet) { // BaseGreet class doesn't exists
return true;
}
return false;
}
}
class BaseGreet {}
class ObjectChecker
{
public function isInstanceOfBaseGreet($object): bool
{
if ($object instanceof BaseGret) { // typo, BaseGret not exists
return true;
}
return false;
}
}
function isInstanceOf($object) {
if ($object instanceof self) { // invalid: Cannot use "self" when no class scope is active
return true;
}
return false;
}
Recommended
Make sure class/interface you are trying to check against exists and doesn't have any typo:
class BaseGreet
{
public function getMessage(): string
{
return 'Hello';
}
}
class ObjectChecker
{
public function isInstanceOfBaseGreet($object): bool
{
if ($object instanceof BaseGreet) {
return true;
}
return false;
}
}
Make sure there is not typo in class/interface name:
class BaseGreet {}
class ObjectChecker
{
public function isInstanceOfBaseGreet($object): bool
{
if ($object instanceof BaseGreet) {
return true;
}
return false;
}
}
Always use self/parent inside class scope:
class ObjectChecker
{
public function isInstanceOfObjectChecker($object): bool
{
if ($object instanceof self) {
return true;
}
return false;
}
}