PHP 8.4 deprecation: explicit nullable type must be used

[lianatech-matias-ylipelto]

Description

PHP 8.4 has deprecated implicitly marking parameters as nullable.

vendor/promphp/prometheus_client_php/src/Prometheus/RegistryInterface.php:94 Prometheus\RegistryInterface::registerHistogram(): Implicitly marking parameter $buckets as nullable is deprecated, the explicit nullable type must be used instead

These deprecation warnings could be fixed like this I think:

    public function registerHistogram(
        string $namespace,
        string $name,
        string $help,
        array $labels = [],
-       array $buckets = null
+       ?array $buckets = null
    ): Histogram;

Support for nullable types has been around since PHP 7.1.

Links

• https://www.php.net/manual/en/migration84.deprecated.php#migration84.deprecated.core.implicitly-nullable-parameter
• https://github.com/PromPHP/prometheus_client_php/blob/v2.12.0/src/Prometheus/RegistryInterface.php#L94-L100