Add logging to error rendering failures

When error rendering fails it can be tedious to diagnose what the
problem is. Having some logging when rendering fails could help triage
the problem and get to a solution quicker.

Refs #17603

src/Error/Renderer/WebExceptionRenderer.php

@@ -35,6 +35,7 @@
 use Cake\Http\ResponseEmitter;
 use Cake\Http\ServerRequest;
 use Cake\Http\ServerRequestFactory;
+use Cake\Log\Log;
 use Cake\Routing\Exception\MissingRouteException;
 use Cake\Routing\Router;
 use Cake\Utility\Inflector;
@@ -161,6 +162,7 @@ protected function _getController(): Controller
             $request = $request->withAttribute('params', $routerRequest->getAttribute('params'));
         }
 
+        $class = "";
         try {
             $params = $request->getAttribute('params');
             $params['controller'] = 'Error';
@@ -185,6 +187,11 @@ protected function _getController(): Controller
             $controller = new $class($request);
             $controller->startupProcess();
         } catch (Throwable $e) {
+            Log::warning(
+                "Failed to construct or call startup() on the resolved controller class of `$class`. " .
+                    "Using Fallback Controller instead. Error {$e->getMessage()}",
+                'cake.error'
+            );
             $controller = null;
         }
 
@@ -412,6 +419,10 @@ protected function _outputMessage(string $template): Response
 
             return $this->_shutdown();
         } catch (MissingTemplateException $e) {
+            Log::warning(
+                "MissingTemplateException - Failed to render error template `{$template}`. Error: {$e->getMessage()}",
+                'cake.error'
+            );
             $attributes = $e->getAttributes();
             if (
                 $e instanceof MissingLayoutException ||
@@ -422,13 +433,21 @@ protected function _outputMessage(string $template): Response
 
             return $this->_outputMessage('error500');
         } catch (MissingPluginException $e) {
+            Log::warning(
+                "MissingPluginException - Failed to render error template `{$template}`. Error: {$e->getMessage()}",
+                'cake.error'
+            );
             $attributes = $e->getAttributes();
             if (isset($attributes['plugin']) && $attributes['plugin'] === $this->controller->getPlugin()) {
                 $this->controller->setPlugin(null);
             }
 
             return $this->_outputMessageSafe('error500');
         } catch (Throwable $outer) {
+            Log::warning(
+                "Throwable - Failed to render error template `{$template}`. Error: {$outer->getMessage()}",
+                'cake.error'
+            );
             try {
                 return $this->_outputMessageSafe('error500');
             } catch (Throwable $inner) {

templates/Error/missing_controller.php

@@ -22,6 +22,7 @@
 $namespace = Configure::read('App.namespace');
 $prefixNs = $prefixPath = '';
 
+$controller = (string)$controller;
 $incompleteInflection = (str_contains($controller, '_') || str_contains($controller, '-'));
 $originalClass = $controller;
 

tests/TestCase/Error/ExceptionTrapTest.php

@@ -260,7 +260,8 @@ public function testSkipLogException(): void
         ob_get_clean();
 
         $logs = Log::engine('test_error')->read();
-        $this->assertEmpty($logs);
+        $this->assertCount(1, $logs);
+        $this->assertStringContainsString('MissingTemplateException - Failed to render', $logs[0]);
         $this->assertTrue($this->triggered, 'Should have triggered event when skipping logging.');
     }
 

tests/TestCase/Error/Middleware/ErrorHandlerMiddlewareTest.php

@@ -318,7 +318,7 @@ public function testHandleExceptionLogAttributes(): void
         $request = ServerRequestFactory::fromGlobals();
         $middleware = new ErrorHandlerMiddleware(['log' => true]);
         $handler = new TestRequestHandler(function (): void {
-            throw new MissingControllerException(['class' => 'Articles']);
+            throw new MissingControllerException(['controller' => 'Articles']);
         });
         $result = $middleware->process($request, $handler);
         $this->assertSame(404, $result->getStatusCode());
@@ -329,7 +329,7 @@ public function testHandleExceptionLogAttributes(): void
             $logs[0]
         );
         $this->assertStringContainsString('Exception Attributes:', $logs[0]);
-        $this->assertStringContainsString("'class' => 'Articles'", $logs[0]);
+        $this->assertStringContainsString("'controller' => 'Articles'", $logs[0]);
         $this->assertStringContainsString('Request URL:', $logs[0]);
     }