Assert::interfaceExists($value, $message = '')

[bmeynell]

As of PHP 5.02 class_exists,

No longer returns TRUE for defined interfaces. Use interface_exists().

Quick Test:

interface MyInterface {}
class MyClass {}
echo PHP_VERSION; // 7.1.12-3+ubuntu14.04.1+deb.sury.org+1
var_dump(interface_exists(MyInterface::class)); // bool(true)
var_dump(class_exists(MyInterface::class)); // bool(false)
var_dump(interface_exists(MyClass::class)); // bool(false)
var_dump(class_exists(MyClass::class)); // bool(true)

interfaceExists() Proposal:

public static function interfaceExists($value, $message = '')
{
    if (!interface_exists($value)) {
        static::reportInvalidArgument(sprintf(
            $message ?: 'Expected an existing interface name. Got: %s',
            static::valueToString($value)
        ));
    }
}

... which is akin to classExists():

https://github.com/webmozart/assert/blob/23bf61bc8a7cc229d7ce8689b1bf818a9e192cac/src/Assert.php#L817-L825

[Nyholm]

You are correct. Thank you.

Can you elaborate the use case for Assert::interfaceExists?

[bmeynell]

Specialized collection object that only allows objects to be added to it that implement a specific interface. The interface is defined in the collection's constructor, which is where check for its existence occurs.