Fix FC layer for the event dispatcher under Symfony < 4.3

phpstan.neon

@@ -5,6 +5,10 @@ parameters:
         - tests/
     ignoreErrors:
         - "#no value type specified in iterable type Symfony\\\\Component\\\\Process\\\\Process\\.$#"
+        -
+            message: "#^Else branch is unreachable because previous condition is always true\\.$#"
+            count: 1
+            path: src/Configuration/DependencyInjection/ParallelContainerDefinition.php
         -
             message: "#^Class Symfony\\\\Component\\\\EventDispatcher\\\\Event not found\\.$#"
             count: 2
@@ -21,6 +25,10 @@ parameters:
             message: "#^Method Tests\\\\Unit\\\\Configuration\\\\CoverageConfigurationTest\\:\\:getService\\(\\) has no return typehint specified\\.$#"
             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;
@@ -35,7 +36,6 @@
 use Symfony\Component\EventDispatcher\DependencyInjection\RegisterListenersPass;
 use Symfony\Component\EventDispatcher\EventDispatcher;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface as SymfonyEventDispatcherInterface;
-use Symfony\Component\EventDispatcher\LegacyEventDispatcherProxy;
 
 class ParallelContainerDefinition
 {
@@ -82,15 +82,16 @@ private function configureConfiguration(ContainerBuilder $container): void
 
     private function configureEventDispatcher(ContainerBuilder $container): void
     {
-        $eventDispatcher = new Definition(EventDispatcher::class);
-        if (class_exists(LegacyEventDispatcherProxy::class)) {
-            $container->setDefinition(LegacyEventDispatcherProxy::class, new Definition(LegacyEventDispatcherProxy::class));
-            $eventDispatcher->setDecoratedService(LegacyEventDispatcherProxy::class);
+        $dispatcher = new Definition(EventDispatcher::class);
+        $container->setDefinition(SymfonyEventDispatcherInterface::class, $dispatcher);
+
+        if (is_subclass_of(EventDispatcher::class, PsrEventDispatcherInterface::class)) {
+            $container->setAlias(PsrEventDispatcherInterface::class, SymfonyEventDispatcherInterface::class);
+        } else {
+            $container->setDefinition(ForwardCompatEventDispatcher::class, new Definition(ForwardCompatEventDispatcher::class, [new Reference(SymfonyEventDispatcherInterface::class)]));
+            $container->setAlias(PsrEventDispatcherInterface::class, ForwardCompatEventDispatcher::class);
         }
 
-        $container->setDefinition(SymfonyEventDispatcherInterface::class, $eventDispatcher);
-        $container->setAlias(PsrEventDispatcherInterface::class, SymfonyEventDispatcherInterface::class);
-
         $container->addCompilerPass(
             new RegisterListenersPass(
                 SymfonyEventDispatcherInterface::class,

src/Lifecycle/ForwardCompatEventDispatcher.php

@@ -0,0 +1,26 @@
+<?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;
+
+    public function __construct(SymfonyEventDispatcherInterface $eventDispatcher)
+    {
+        $this->eventDispatcher = $eventDispatcher;
+    }
+
+    public function dispatch(object $event): object
+    {
+        $this->eventDispatcher->dispatch(\get_class($event), $event);
+
+        return $event;
+    }
+}