Fix FC layer for the event dispatcher under Symfony < 4.3

phpstan.neon

@@ -21,6 +21,10 @@ parameters:
             message: "#^Method Tests\\\\Unit\\\\Configuration\\\\CoverageConfigurationTest\\:\\:getService\\(\\) has no return typehint specified\\.$#"
             count: 1
             path: tests/Unit/Configuration/CoverageConfigurationTest.php
+        -
+            message: "#^Method Tests\\\\Unit\\\\Configuration\\\\OutputFileTest\\:\\:testIsEmpty\\(\\) has parameter \\$emptyFile with no typehint specified\\.$#"
+            count: 1
+            path: tests/Unit/Configuration/OutputFileTest.php
     excludes_analyse:
         - tests/Stub/
         - src/Lifecycle/ForwardCompatEventDispatcher.php

src/Configuration/DependencyInjection/ParallelContainerDefinition.php

@@ -11,6 +11,7 @@
 use Paraunit\File\Cleaner;
 use Paraunit\File\TempDirectory;
 use Paraunit\Filter\Filter;
+use Paraunit\Lifecycle\ForwardCompatEventDispatcher;
 use Paraunit\Printer\ConsoleFormatter;
 use Paraunit\Printer\FailuresPrinter;
 use Paraunit\Printer\FilesRecapPrinter;
@@ -83,9 +84,9 @@ private function configureConfiguration(ContainerBuilder $container): void
     private function configureEventDispatcher(ContainerBuilder $container): void
     {
         $eventDispatcher = new Definition(EventDispatcher::class);
-        if (class_exists(LegacyEventDispatcherProxy::class)) {
+        if (! class_exists(LegacyEventDispatcherProxy::class)) {
             $container->setDefinition(LegacyEventDispatcherProxy::class, new Definition(LegacyEventDispatcherProxy::class));
-            $eventDispatcher->setDecoratedService(LegacyEventDispatcherProxy::class);
+            $eventDispatcher->setDecoratedService(ForwardCompatEventDispatcher::class);
         }
 
         $container->setDefinition(SymfonyEventDispatcherInterface::class, $eventDispatcher);

src/Lifecycle/ForwardCompatEventDispatcher.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Paraunit\Lifecycle;
+
+use Psr\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface as SymfonyEventDispatcherInterface;
+
+class ForwardCompatEventDispatcher implements EventDispatcherInterface
+{
+    /** @var SymfonyEventDispatcherInterface */
+    private $eventDispatcher;
+
+    private function __construct(EventDispatcherInterface $eventDispatcher)
+    {
+        $this->eventDispatcher = $eventDispatcher;
+    }
+
+    public static function decorate(SymfonyEventDispatcherInterface $dispatcher): self
+    {
+        return new self($dispatcher);
+    }
+
+    public function dispatch(object $event): object
+    {
+        $this->eventDispatcher->dispatch(\get_class($event), $event);
+
+        return $event;
+    }
+}