feature #46715 [Clock] A new component to decouple applications from the system clock (nicolas-grekas)

This PR was squashed before being merged into the 6.2 branch.

Discussion
----------

[Clock] A new component to decouple applications from the system clock

| Q             | A
| ------------- | ---
| Branch?       | 6.2
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

After watching @afilina's talk at SymfonyWorld Online last week + listening to her using a "clock" service to improve testability of time-sensitive logics, I decided to propose this new "Clock" component. This also relates to the ongoing efforts to standardize a `ClockInterface` in [PSR-20](https://github.com/php-fig/clock).

This PR provides a `ClockInterface`, with 3 methods:
- `now(): \DateTimeImmutable` is designed to be compatible with the envisioned PSR-20;
- `sleep(float|int $seconds): void` advances the clock by the provided number of seconds;
- `withTimeZone(): static` changes the time zone returned by `now()`.

The `sleep()` methods takes inspiration from `ClockMock` in the PhpUnitBridge, where this proved useful to improve testability. Ideally, we could use this component everywhere measuring the current time is needed and stop relying on  `ClockMock`.

This PR provides 3 clock implementations:
- `NativeClock` which relies on the system clock;
- `MockClock` which allows mocking the time;
- `MonotonicClock` which relies on `hrtime()` to provide a monotonic clock.

If this gets accepted, I'll follow up with a PR to add clock services to FrameworkBundle and we'll then be able to see where we could use such clock services in other components. I hope PSR-20 will be stabilized by Symfony 6.2, but this is not required for this PR to be useful.

Commits
-------

9db08e40d4 [Clock] A new component to decouple applications from the system clock

Author: fabpot

DependencyInjection/FrameworkExtension.php

@@ -20,7 +20,6 @@
 use PHPStan\PhpDocParser\Parser\PhpDocParser;
 use Psr\Cache\CacheItemPoolInterface;
 use Psr\Container\ContainerInterface as PsrContainerInterface;
-use Psr\EventDispatcher\EventDispatcherInterface as PsrEventDispatcherInterface;
 use Psr\Http\Client\ClientInterface;
 use Psr\Log\LoggerAwareInterface;
 use Symfony\Bridge\Monolog\Processor\DebugProcessor;
@@ -40,6 +39,7 @@
 use Symfony\Component\Cache\Marshaller\DefaultMarshaller;
 use Symfony\Component\Cache\Marshaller\MarshallerInterface;
 use Symfony\Component\Cache\ResettableInterface;
+use Symfony\Component\Clock\ClockInterface;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\Config\Loader\LoaderInterface;
@@ -277,8 +277,9 @@ public function load(array $configs, ContainerBuilder $container)
         $loader->load('fragment_renderer.php');
         $loader->load('error_renderer.php');
 
-        if (ContainerBuilder::willBeAvailable('psr/event-dispatcher', PsrEventDispatcherInterface::class, ['symfony/framework-bundle'])) {
-            $container->setAlias(PsrEventDispatcherInterface::class, 'event_dispatcher');
+        if (!ContainerBuilder::willBeAvailable('symfony/clock', ClockInterface::class, ['symfony/framework-bundle'])) {
+            $container->removeDefinition('clock');
+            $container->removeAlias(ClockInterface::class);
         }
 
         $container->registerAliasForArgument('parameter_bag', PsrContainerInterface::class);

Resources/config/services.php

@@ -11,8 +11,11 @@
 
 namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 
+use Psr\EventDispatcher\EventDispatcherInterface as PsrEventDispatcherInterface;
 use Symfony\Bundle\FrameworkBundle\CacheWarmer\ConfigBuilderCacheWarmer;
 use Symfony\Bundle\FrameworkBundle\HttpCache\HttpCache;
+use Symfony\Component\Clock\ClockInterface;
+use Symfony\Component\Clock\NativeClock;
 use Symfony\Component\Config\Loader\LoaderInterface;
 use Symfony\Component\Config\Resource\SelfCheckingResourceChecker;
 use Symfony\Component\Config\ResourceCheckerConfigCacheFactory;
@@ -77,6 +80,7 @@ class_exists(WorkflowEvents::class) ? WorkflowEvents::ALIASES : []
             ->tag('event_dispatcher.dispatcher', ['name' => 'event_dispatcher'])
         ->alias(EventDispatcherInterfaceComponentAlias::class, 'event_dispatcher')
         ->alias(EventDispatcherInterface::class, 'event_dispatcher')
+        ->alias(PsrEventDispatcherInterface::class, 'event_dispatcher')
 
         ->set('http_kernel', HttpKernel::class)
             ->public()
@@ -224,6 +228,9 @@ class_exists(WorkflowEvents::class) ? WorkflowEvents::ALIASES : []
             ->args([service(KernelInterface::class), service('logger')->nullOnInvalid()])
             ->tag('kernel.cache_warmer')
 
+        ->set('clock', NativeClock::class)
+        ->alias(ClockInterface::class, 'clock')
+
         // register as abstract and excluded, aka not-autowirable types
         ->set(LoaderInterface::class)->abstract()->tag('container.excluded')
         ->set(Request::class)->abstract()->tag('container.excluded')