Description

Currently the RateLimiter component has time dependency hardcoded, with lot of microtime(true) calls everywhere making it unmockable and thus untestable.

Internally Symfony leverages the \Symfony\Bridge\PhpUnit\ClockMock::register to mock and test the component, but this is not a suitable solution for the component consumers.

Example

The Optimal solution would be to set for every class the ClockInterface dependency in the constructor, but of course this would be a BC Break; we can do it in the next major, but not now in v6.

A backward compatible workaround for v6 could be to have a dedicated clock registry that every RateLimiter class consumes, something like:

namespace Symfony\Component\RateLimiter;

use Symfony\Component\Clock\ClockInterface;
use Symfony\Component\Clock\NativeClock;

/**
 * @deprecated Symfony v7 is going to have explicit ClockInterface dependency
 */
final class RateLimiterClockRegistry
{
    private static ClockInterface $clock;

    public static function setClock(ClockInterface $clock): void
    {
        self::$clock = $clock;
    }

    public static function getClock(): ClockInterface
    {
        if (! isset(self::$clock)) {
            self::$clock = new NativeClock();
        }

        return self::$clock;
    }
}

Then all call can be edited to:

-$now = microtime(true);
+$now = (float) RateLimiterClockRegistry::getClock()->format("U.u");

And the component become mockable by consumers as well.

I am willing to create the PR if this sounds good to the maintainers.