Invalid usage of class constant fetch expression PHP-W1006
Bug risk
18 days ago
—
a year old
Access to constant ACTIVE on an unknown class SemesterStatus
19 $extern_id = Role::getObjectIdByName(Role::COLLEGIST, 'extern');
20 $collegist->roles()->detach(Role::firstWhere('name', Role::COLLEGIST)->id);
21 $collegist->roles()->attach(Role::firstWhere('name', Role::COLLEGIST)->id, ['object_id' => $extern_id]);
22 $collegist->setStatusFor(Semester::current(), SemesterStatus::ACTIVE);23 }
24 }
25
Description
The class constant you're trying to access isn't valid and could lead to runtime errors.
This issue is raised for the following cases:
- Trying to access a class that doesn't exist.
- Using
self/static/parentoutside a class. - Trying to access a class constant defined in a class that is not in scope.
- Accessing a private/undefined constant in a class.
- Trying to access the
::classconstant on a dynamic string. - Using the
::classconstant on an expression in PHP < 8.0. Accessing this value on an expression is supported only in PHP 8.0 and later.
Any of the operations mentioned above would result in a fatal runtime error, and may potentially crash the application. Avoid performing such operations.
Bad practice
class Version
{
private const PHP_74 = 70400;
public const PHP_80 = 80000;
}
echo PhpVersion::PHP_80; // invalid: class "PhpVersion" doesn't exist
echo self::PHP_74; // invalid: cannot use "self" outside of a class
echo Version::PHP_56; // invalid: class constant "PHP_56" is undefined
$version = new Version;
echo $version::class; // note: this will only work on PHP 8.0 or later
Recommended
class Version
{
public const PHP_56 = 50600;
public const PHP_74 = 70400;
public const PHP_80 = 80000;
}
// valid: make sure class exists and constant is defined
echo Version::PHP_80;
// valid: make sure to define constant that is being accessed
echo Version::PHP_56;
// valid: change visibility to public, or implement a getter method to retrieve the private constant or properties
echo Version::PHP_74;