[TASK] Tune RenderingContext withAttribute() and getAttribute()

getAttribute($className) now always returns an instance of
$className, or throws. This avoids checking the returned
instance and helps with type hinting in IDEs.

src/Core/Rendering/AttributeNotSetException.php

@@ -0,0 +1,10 @@
+<?php
+
+/*
+ * This file belongs to the package "TYPO3 Fluid".
+ * See LICENSE.txt that was shipped with this package.
+ */
+
+namespace TYPO3Fluid\Fluid\Core\Rendering;
+
+class AttributeNotSetException extends \TYPO3Fluid\Fluid\Core\Exception {}

src/Core/Rendering/RenderingContext.php

@@ -363,32 +363,18 @@ public function buildParserConfiguration()
         return $parserConfiguration;
     }
 
-    /**
-     * Retrieve a single attribute.
-     *
-     * @see withAttribute()
-     * @param string $name The attribute name.
-     * @return object|null  null if the specified attribute hasn't been set
-     */
-    public function getAttribute(string $name): ?object
+    public function getAttribute(string $className): object
     {
-        return $this->attributes[$name] ?? null;
+        if (!isset($this->attributes[$className])) {
+            throw new AttributeNotSetException('An attribute of type ' . $className . ' has not been set', 1719394231);
+        }
+        return $this->attributes[$className];
     }
 
-    /**
-     * Return an instance with the specified attribute.
-     *
-     * This method allows you to attach arbitrary objects to the
-     * rendering context to be used later e. g. in ViewHelpers.
-     *
-     * @param string $name The attribute name.
-     * @param object $value The value of the attribute.
-     * @return static
-     */
-    public function withAttribute(string $name, object $value): static
+    public function withAttribute(string $className, object $value): static
     {
         $clonedObject = clone $this;
-        $clonedObject->attributes[$name] = $value;
+        $clonedObject->attributes[$className] = $value;
         return $clonedObject;
     }
 

src/Core/Rendering/RenderingContextInterface.php

@@ -181,23 +181,23 @@ public function getControllerAction();
     public function setControllerAction($action);
 
     /**
-     * Retrieve a single attribute.
+     * Retrieve a single attribute instance.
      *
-     * @see withAttribute()
-     * @param string $name The attribute name.
-     * @return object|null  null if the specified attribute hasn't been set
+     * @template T of object
+     * @param class-string<T> $className
+     * @return T
      */
-    public function getAttribute(string $name): ?object;
+    public function getAttribute(string $className): object;
 
     /**
-     * Return an instance with the specified attribute.
+     * Return an instance with the specified attribute being attached.
      *
      * This method allows you to attach arbitrary objects to the
      * rendering context to be used later e. g. in ViewHelpers.
      *
-     * @param string $name The attribute name.
-     * @param object $value The value of the attribute.
-     * @return static
+     * @template T of object
+     * @param class-string<T> $className
+     * @param T $value
      */
-    public function withAttribute(string $name, object $value): RenderingContextInterface;
+    public function withAttribute(string $className, object $value): RenderingContextInterface;
 }

tests/Unit/Core/Rendering/RenderingContextTest.php

@@ -17,6 +17,7 @@
 use TYPO3Fluid\Fluid\Core\Compiler\TemplateCompiler;
 use TYPO3Fluid\Fluid\Core\Parser\TemplateParser;
 use TYPO3Fluid\Fluid\Core\Parser\TemplateProcessorInterface;
+use TYPO3Fluid\Fluid\Core\Rendering\AttributeNotSetException;
 use TYPO3Fluid\Fluid\Core\Rendering\RenderingContext;
 use TYPO3Fluid\Fluid\Core\Variables\VariableProviderInterface;
 use TYPO3Fluid\Fluid\Core\ViewHelper\ViewHelperInvoker;
@@ -102,10 +103,16 @@ public function withAndGetAttribute(): void
     {
         $object = new stdClass();
         $object->test = 'value';
-
         $subject = new RenderingContext();
-        $clonedSubject = $subject->withAttribute('test', $object);
-        self::assertNull($subject->getAttribute('test'));
-        self::assertEquals($object, $clonedSubject->getAttribute('test'));
+        $clonedSubject = $subject->withAttribute(stdClass::class, $object);
+        self::assertEquals($object, $clonedSubject->getAttribute(stdClass::class));
+    }
+
+    #[Test]
+    public function getAttributeThrowsWithNoSuchAttribute(): void
+    {
+        $this->expectException(AttributeNotSetException::class);
+        $this->expectExceptionCode(1719394231);
+        (new RenderingContext())->getAttribute(stdClass::class);
     }
 }