Issue #2405241 by philipnorton42, jibran, dawehner, andrewmacpherson: Add...

Issue #2405241 by philipnorton42, jibran, dawehner, andrewmacpherson: Add helpful exception message in CustomAccessCheck

core/lib/Drupal/Core/Access/CustomAccessCheck.php

@@ -61,7 +61,14 @@ public function __construct(ControllerResolverInterface $controller_resolver, Ac
    *   The access result.
    */
   public function access(Route $route, RouteMatchInterface $route_match, AccountInterface $account) {
-    $callable = $this->controllerResolver->getControllerFromDefinition($route->getRequirement('_custom_access'));
+    try {
+      $callable = $this->controllerResolver->getControllerFromDefinition($route->getRequirement('_custom_access'));
+    }
+    catch (\InvalidArgumentException $e) {
+      // The custom access controller method was not found.
+      throw new \BadMethodCallException(sprintf('The "%s" method is not callable as a _custom_access callback in route "%s"', $route->getRequirement('_custom_access'), $route->getPath()));
+    }
+
     $arguments_resolver = $this->argumentsResolverFactory->getArgumentsResolver($route_match, $account);
     $arguments = $arguments_resolver->getArguments($callable);
 

core/tests/Drupal/Tests/Core/Access/CustomAccessCheckTest.php

@@ -9,8 +9,13 @@
 
 use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Access\CustomAccessCheck;
+use Drupal\Core\Controller\ControllerResolver;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\Core\Session\AccountInterface;
 use Drupal\Tests\UnitTestCase;
 use Symfony\Component\Routing\Route;
+use Drupal\Core\DependencyInjection\ClassResolverInterface;
+use Symfony\Bridge\PsrHttpMessage\HttpMessageFactoryInterface;
 
 /**
  * @coversDefaultClass \Drupal\Core\Access\CustomAccessCheck
@@ -106,6 +111,34 @@ public function testAccess() {
     $this->assertEquals(AccessResult::allowed(), $this->accessChecker->access($route, $route_match, $account));
   }
 
+  /**
+   * Tests the access method exception for invalid access callbacks.
+   */
+  public function testAccessException() {
+    // Create two mocks for the ControllerResolver constructor.
+    $httpMessageFactory = $this->getMockBuilder(HttpMessageFactoryInterface::class)->getMock();
+    $controllerResolver = $this->getMockBuilder(ClassResolverInterface::class)->getMock();
+
+    // Re-create the controllerResolver mock with proxy to original methods.
+    $this->controllerResolver = $this->getMockBuilder(ControllerResolver::class)
+      ->setConstructorArgs([$httpMessageFactory, $controllerResolver])
+      ->enableProxyingToOriginalMethods()
+      ->getMock();
+
+    // Overwrite the access checker using the newly mocked controller resolve.
+    $this->accessChecker = new CustomAccessCheck($this->controllerResolver, $this->argumentsResolverFactory);
+
+    // Add a route with a _custom_access route that doesn't exist.
+    $route = new Route('/test-route', [], ['_custom_access' => '\Drupal\Tests\Core\Access\NonExistentController::nonExistentMethod']);
+    $route_match = $this->getMock(RouteMatchInterface::class);
+    $account = $this->getMock(AccountInterface::class);
+
+    $this->setExpectedException(\BadMethodCallException::class, 'The "\Drupal\Tests\Core\Access\NonExistentController::nonExistentMethod" method is not callable as a _custom_access callback in route "/test-route"');
+
+    // Run the access check.
+    $this->accessChecker->access($route, $route_match, $account);
+  }
+
 }
 
 class TestController {