Incorrect PHP reflection type for Memcached::cas $cas_token

[gdejong]

The first argument ($cas_token) to Memcached::cas is a float according to the documentation.

However when using Reflection to list the parameters it determines that the $cas_token is of type string.

PHP script:

<?php
declare(strict_types=1);

$class = Memcached::class;
$method_to_inspect = "cas";

$method = new ReflectionMethod($class, $method_to_inspect);

echo "PHP version: " . PHP_VERSION . PHP_EOL;
echo "memcached version: " . phpversion("memcached") . PHP_EOL;
echo "Reflecting $class::$method_to_inspect" . PHP_EOL;


foreach ($method->getParameters() as $parameter) {
    echo "-  " . $parameter->getDeclaringClass()->getName() . "::" . $parameter->getName() . PHP_EOL;
    echo "   " . "type: " . $parameter->getType()->getName() . PHP_EOL;
}

results in

PHP version: 8.1.12
memcached version: 3.2.0
Reflecting Memcached::cas
-  Memcached::cas_token
   type: string
-  Memcached::key
   type: string
-  Memcached::value
   type: mixed
-  Memcached::expiration
   type: int

Dockerfile:

FROM php:8.1-cli-alpine

COPY --from=mlocati/php-extension-installer /usr/bin/install-php-extensions /usr/local/bin/

RUN chmod uga+x /usr/local/bin/install-php-extensions && install-php-extensions memcached

Where does this inconsistency come from and can it be resolved?

A possible explanation is https://github.com/php-memcached-dev/php-memcached/blob/master/php_memcached.stub.php#L34
This stub file type hints the $cas_token parameter as being a string.

public function cas(string $cas_token, string $key, mixed $value, int $expiration=0): bool {}

[remicollet]

According to the code, the $cas_token should be an unsigned 64-bit integer (library side). In the extension valid type are integer, float and string (converted to uint64_t), but all type are accepted (so mixed).