perf(laravel): memoize the Symfony RouteCollection in Router

Router::getRouteCollection() rebuilt the entire Symfony RouteCollection
on every call via Illuminate\Routing\AbstractRouteCollection::toSymfonyRouteCollection(),
converting the whole Laravel route table each time. generate() is called
once per IRI during normalization, so a single response with several
relations triggered the full conversion dozens of times (~65 for ~8
relations in profiling).

Routes are static within a request and Router is a per-request singleton,
so the built collection is cached on the instance.

Also type SkolemIriConverter's constructor against
Symfony\Component\Routing\RouterInterface instead of the final concrete
Router, so consumers are no longer pinned to the concrete class.

Closes #8337

Author: soyuka

src/Laravel/Routing/Router.php

@@ -37,6 +37,7 @@ final class Router implements RouterInterface, UrlGeneratorInterface
     ];
 
     private RequestContext $context;
+    private ?RouteCollection $routeCollection = null;
 
     public function __construct(private readonly BaseRouter $router, private readonly int $urlGenerationStrategy = UrlGeneratorInterface::ABS_PATH)
     {
@@ -63,10 +64,14 @@ public function getContext(): RequestContext
      */
     public function getRouteCollection(): RouteCollection
     {
+        if (null !== $this->routeCollection) {
+            return $this->routeCollection;
+        }
+
         /** @var \Illuminate\Routing\RouteCollection $routes */
         $routes = $this->router->getRoutes();
 
-        return $routes->toSymfonyRouteCollection();
+        return $this->routeCollection = $routes->toSymfonyRouteCollection();
     }
 
     /**

src/Laravel/Routing/SkolemIriConverter.php

@@ -17,6 +17,7 @@
 use ApiPlatform\Metadata\IriConverterInterface;
 use ApiPlatform\Metadata\Operation;
 use ApiPlatform\Metadata\UrlGeneratorInterface;
+use Symfony\Component\Routing\RouterInterface;
 
 /**
  * {@inheritdoc}
@@ -37,7 +38,7 @@ final class SkolemIriConverter implements IriConverterInterface
      */
     private array $classHashMap = [];
 
-    public function __construct(private readonly Router $router)
+    public function __construct(private readonly RouterInterface $router)
     {
         $this->objectHashMap = new \SplObjectStorage();
     }

src/Laravel/Tests/Unit/Routing/RouterTest.php

@@ -0,0 +1,44 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Laravel\Tests\Unit\Routing;
+
+use ApiPlatform\Laravel\Routing\Router;
+use Illuminate\Routing\Router as BaseRouter;
+use Illuminate\Routing\RouteCollection as IlluminateRouteCollection;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Routing\RouteCollection;
+
+class RouterTest extends TestCase
+{
+    public function testGetRouteCollectionIsMemoizedAcrossCalls(): void
+    {
+        $symfonyRoutes = new RouteCollection();
+
+        $illuminateRoutes = $this->createMock(IlluminateRouteCollection::class);
+        $illuminateRoutes->expects($this->once())
+            ->method('toSymfonyRouteCollection')
+            ->willReturn($symfonyRoutes);
+
+        $baseRouter = $this->createStub(BaseRouter::class);
+        $baseRouter->method('getRoutes')->willReturn($illuminateRoutes);
+
+        $router = new Router($baseRouter);
+
+        $first = $router->getRouteCollection();
+        $second = $router->getRouteCollection();
+
+        $this->assertSame($symfonyRoutes, $first);
+        $this->assertSame($first, $second);
+    }
+}