Validate route aliases before registration

Author: ChiragAgg5k

src/Http/Route.php

@@ -87,6 +87,8 @@ public function path(string $path): self
      */
     public function alias(string $path): self
     {
+        Router::validateRouteAlias($path, [$this->method, ...$this->additionalMethods]);
+
         Router::addRouteAlias($path, $this);
 
         foreach ($this->additionalMethods as $method) {

src/Http/Router.php

@@ -108,6 +108,28 @@ public static function addRoute(Route $route): void
         }
     }
 
+    /**
+     * Validate that a route alias can be registered for every supplied method.
+     *
+     * @param array<int, string> $methods
+     *
+     * @throws Exception
+     */
+    public static function validateRouteAlias(string $path, array $methods): void
+    {
+        [$alias] = self::preparePath($path);
+
+        foreach ($methods as $method) {
+            if (!\array_key_exists($method, self::$routes)) {
+                throw new Exception("Method ({$method}) not supported.");
+            }
+
+            if (\array_key_exists($alias, self::$routes[$method]) && !self::$allowOverride) {
+                throw new Exception("Route for ({$method}:{$alias}) already registered.");
+            }
+        }
+    }
+
     /**
      * Add route to router.
      *

tests/RouterTest.php

@@ -180,6 +180,19 @@ public function testRoutesCrossPathAliases(): void
         $this->assertEquals($route, Router::match(Http::REQUEST_METHOD_POST, '/a')?->route);
         $this->assertEquals($route, Router::match(Http::REQUEST_METHOD_GET, '/a-old')?->route);
         $this->assertEquals($route, Router::match(Http::REQUEST_METHOD_POST, '/a-old')?->route);
+
+        $routePOST = Http::routes(Http::REQUEST_METHOD_POST, '/b')->alias('/b-old');
+        $routeGETPOST = Http::routes([Http::REQUEST_METHOD_GET, Http::REQUEST_METHOD_POST], '/c');
+
+        try {
+            $routeGETPOST->alias('/b-old');
+            $this->fail('Expected duplicate route alias exception.');
+        } catch (\Exception $exception) {
+            $this->assertSame('Route for (POST:b-old) already registered.', $exception->getMessage());
+        }
+
+        $this->assertNull(Router::match(Http::REQUEST_METHOD_GET, '/b-old'));
+        $this->assertEquals($routePOST, Router::match(Http::REQUEST_METHOD_POST, '/b-old')?->route);
     }
 
     public function testCannotRegisterDuplicateRouteMethod(): void