Wrap dynamic parent expression errors

CHANGELOG

@@ -4,6 +4,7 @@
  * Fix the `default` filter fallback emitting an undefined variable warning when it uses the null-safe operator
  * Fix the `matches` operator silently treating PCRE execution errors as non-matches
  * Fix `TemplateWrapper::streamBlock()`, `TemplateWrapper::hasBlock()`, and `TemplateWrapper::getBlockNames()` omitting environment globals
+ * Fix exceptions from dynamic parent expressions escaping without template context
  * Add the `HtmlExtension::htmlAttrValue()` method to resolve a single HTML attribute value the way the `html_attr` function renders it
  * Fix `html_attr` JSON encoding a `Stringable` value in a `data-*` attribute instead of using its string representation
  * Add documentation comments to attach metadata to nodes (experimental)

src/Template.php

@@ -89,7 +89,13 @@ abstract class Template
         // resolved against a parent, or yieldBlock() into a pre-warmed instance).
         $this->ensureSecurityChecked();
 
-        if (!$parent = $this->doGetParent($context)) {
+        try {
+            $parent = $this->doGetParent($context);
+        } catch (\Throwable $e) {
+            $this->handleException($e);
+        }
+
+        if (!$parent) {
             return false;
         }
 

tests/TemplateWrapperTest.php

@@ -20,9 +20,13 @@ namespace Twig\Tests;
  * file that was distributed with this source code.
  */
 
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Twig\Environment;
+use Twig\Error\LoaderError;
+use Twig\Error\RuntimeError;
 use Twig\Loader\ArrayLoader;
+use Twig\TwigFunction;
 
 class TemplateWrapperTest extends TestCase
 {
@@ -89,6 +93,52 @@ class TemplateWrapperTest extends TestCase
         $this->assertSame('FOOBAR', $streamed);
     }
 
+    /**
+     * @dataProvider provideDynamicParentFailures
+     */
+    #[DataProvider('provideDynamicParentFailures')]
+    public function testDynamicParentFailuresAreWrapped(string $template, ?TwigFunction $function, string $previousException): void
+    {
+        $twig = new Environment(new ArrayLoader(['index' => $template]));
+        if (null !== $function) {
+            $twig->addFunction($function);
+        }
+
+        foreach ([
+            'block introspection' => static fn () => $twig->load('index')->getBlockNames(),
+            'rendering' => static fn () => $twig->render('index'),
+        ] as $entryPoint => $call) {
+            try {
+                $call();
+                $this->fail(\sprintf('Resolving the dynamic parent during %s must fail.', $entryPoint));
+            } catch (RuntimeError $e) {
+                $this->assertSame('index', $e->getSourceContext()->getName());
+                $this->assertSame(1, $e->getTemplateLine());
+                $this->assertInstanceOf($previousException, $e->getPrevious());
+            }
+        }
+    }
+
+    public function testDynamicParentTwigErrorsAreNotWrapped(): void
+    {
+        $twig = new Environment(new ArrayLoader(['index' => '{% extends parent %}']));
+
+        try {
+            $twig->load('index')->getBlockNames(['parent' => 'missing']);
+            $this->fail('Loading the dynamic parent must fail.');
+        } catch (LoaderError $e) {
+            $this->assertSame('index', $e->getSourceContext()->getName());
+            $this->assertSame(1, $e->getTemplateLine());
+            $this->assertNull($e->getPrevious());
+        }
+    }
+
+    public static function provideDynamicParentFailures(): iterable
+    {
+        yield 'missing parent variable' => ['{% extends parent %}', null, \TypeError::class];
+        yield 'exception thrown by parent expression' => ['{% extends boom() %}', new TwigFunction('boom', static function (): never { throw new \DomainException('kaboom'); }), \DomainException::class];
+    }
+
     public function testRenderBlock(): void
     {
         $twig = new Environment(new ArrayLoader([