Fix #161: Throw InvalidArgumentException with a clear message when an empty view name is passed to WebViewRenderer render methods

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## 7.4.2 under development
 
 - Enh #150: Minor refactor regular expression for controller name extractor (@vjik)
+- Enh #161: Throw `InvalidArgumentException` with a clear message when an empty view name is passed to `WebViewRenderer` render methods (@samdark)
 
 ## 7.4.1 March 18, 2026
 

src/WebViewRenderer.php

@@ -4,6 +4,7 @@
 
 namespace Yiisoft\Yii\View\Renderer;
 
+use InvalidArgumentException;
 use LogicException;
 use Psr\Http\Message\ResponseFactoryInterface;
 use Psr\Http\Message\ResponseInterface;
@@ -113,10 +114,13 @@ public function getViewPath(): string
      *
      * @psalm-param array<string, mixed> $parameters
      *
+     * @throws InvalidArgumentException If the view name is empty.
      * @return ResponseInterface The response instance.
      */
     public function render(string $view, array $parameters = []): ResponseInterface
     {
+        $this->assertViewNameIsNotEmpty($view);
+
         $commonParameters = $this->getCommonParameters();
         $layoutParameters = $this->getLayoutParameters();
         $metaTags = $this->getMetaTags();
@@ -151,6 +155,7 @@ public function render(string $view, array $parameters = []): ResponseInterface
      *
      * @psalm-param array<string, mixed> $parameters
      *
+     * @throws InvalidArgumentException If the view name is empty.
      * @return ResponseInterface The response instance.
      */
     public function renderPartial(string $view, array $parameters = []): ResponseInterface
@@ -176,10 +181,13 @@ public function renderPartial(string $view, array $parameters = []): ResponseInt
      * @throws Throwable If an error occurred during rendering.
      * @throws ViewNotFoundException If the view file does not exist.
      * @throws RuntimeException If the view cannot be resolved.
+     * @throws InvalidArgumentException If the view name is empty.
      * @return string The rendering result.
      */
     public function renderAsString(string $view, array $parameters = []): string
     {
+        $this->assertViewNameIsNotEmpty($view);
+
         return $this->renderProxy(
             $view,
             $parameters,
@@ -202,6 +210,7 @@ public function renderAsString(string $view, array $parameters = []): string
      * @throws Throwable If an error occurred during rendering.
      * @throws ViewNotFoundException If the view file does not exist.
      * @throws RuntimeException If the view cannot be resolved.
+     * @throws InvalidArgumentException If the view name is empty.
      * @return string The rendering result.
      */
     public function renderPartialAsString(string $view, array $parameters = []): string
@@ -382,6 +391,19 @@ private function renderProxy(
             ->render($layout, ['content' => $content]);
     }
 
+    /**
+     * @throws InvalidArgumentException If the view name is empty.
+     */
+    private function assertViewNameIsNotEmpty(string $view): void
+    {
+        if ($view === '') {
+            throw new InvalidArgumentException(
+                'The view name must not be empty. To return a response without a view, such as JSON, '
+                . 'use an appropriate response factory instead.',
+            );
+        }
+    }
+
     /**
      * Gets injection common parameters merged with parameters specified during rendering.
      *

tests/WebViewRendererTest.php

@@ -6,6 +6,7 @@
 
 use HttpSoft\Message\ResponseFactory;
 use HttpSoft\Message\StreamFactory;
+use InvalidArgumentException;
 use LogicException;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
@@ -486,6 +487,41 @@ public function testWithoutViewPath(): void
         $viewRenderer->getViewPath();
     }
 
+    public static function dataEmptyViewName(): iterable
+    {
+        yield 'render' => ['render'];
+        yield 'renderPartial' => ['renderPartial'];
+        yield 'renderAsString' => ['renderAsString'];
+        yield 'renderPartialAsString' => ['renderPartialAsString'];
+    }
+
+    #[DataProvider('dataEmptyViewName')]
+    public function testEmptyViewName(string $method): void
+    {
+        $renderer = $this->getRenderer();
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage(
+            'The view name must not be empty. To return a response without a view, such as JSON, '
+            . 'create it with a response factory instead.',
+        );
+        $renderer->$method('');
+    }
+
+    public function testEmptyViewNameWithoutViewPath(): void
+    {
+        $renderer = new WebViewRenderer(
+            new ResponseFactory(),
+            new StreamFactory(),
+            new Aliases(),
+            new WebView(__DIR__, new SimpleEventDispatcher()),
+        );
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('The view name must not be empty.');
+        $renderer->render('');
+    }
+
     public function testLazyLoadingInjection(): void
     {
         $container = new SimpleContainer([