feature #40513 [Runtime] make GenericRuntime ... generic (nicolas-grekas)

This PR was merged into the 5.3-dev branch.

Discussion
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[Runtime] make GenericRuntime ... generic

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

This PR will allow #40436 to move to https://github.com/symfony/psr-http-message-bridge
For the record, it builds on a prototype I wrote almost one year ago at https://github.com/tchwork/bootstrapper.

This PR makes the `GenericRuntime` implementation able to auto-discover runtime implementations for specific types.

It uses the autoloader for the discovery: when a closure-app requires or returns a type `Vendor\Foo`, it will use a convention and check if the class `Symfony\Runtime\Vendor\FooRuntime` exists. If yes, it will use it to resolve the corresponding type. Such runtime classes have to extend `GenericRuntime` so that they can use the protected API it provides. This requirement is aligned with the fact that the very convention proposed here is an implementation detail that works when using a `GenericRuntime` as the main runtime (This behavior can be overridden by providing explicit entries in the new `runtimes` option when booting the `GenericRuntime`.)

`SymfonyRuntime` can be used as both the main runtime or a type-specific runtime:
- when used as the main runtime, it configures the typical global-state for Symfony and has a fast codepath for Symfony types, while still being generic.
- it can also be used in another runtime as a way to resolve Symfony types (would typically be useful to #40436 for running Console apps in a PSR-based web app.)

Commits
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33e371e24d [Runtime] make GenericRuntime ... generic

Author: Nyholm

Resources/config/services.php

@@ -38,6 +38,8 @@
 use Symfony\Component\HttpKernel\KernelEvents;
 use Symfony\Component\HttpKernel\KernelInterface;
 use Symfony\Component\HttpKernel\UriSigner;
+use Symfony\Component\Runtime\Runner\Symfony\HttpKernelRunner;
+use Symfony\Component\Runtime\Runner\Symfony\ResponseRunner;
 use Symfony\Component\Runtime\SymfonyRuntime;
 use Symfony\Component\String\LazyString;
 use Symfony\Component\String\Slugger\AsciiSlugger;
@@ -79,6 +81,8 @@ class_exists(WorkflowEvents::class) ? WorkflowEvents::ALIASES : []
                 service('argument_resolver'),
             ])
             ->tag('container.hot_path')
+            ->tag('container.preload', ['class' => HttpKernelRunner::class])
+            ->tag('container.preload', ['class' => ResponseRunner::class])
             ->tag('container.preload', ['class' => SymfonyRuntime::class])
         ->alias(HttpKernelInterface::class, 'http_kernel')