twigphp/Twig · error · RuntimeError

Block " " on template " " does not exist.

Error message

Block "%s" on template "%s" does not exist.

What it means

Thrown by Template::yieldBlock as the final fallback: the requested block name exists neither in the template's own blocks, nor in any merged block set from callers, nor in a parent template. Twig raises a RuntimeError naming the missing block and template. This is the generic 'block not found' failure at render time.

Solutions

1. Fix the block name typo in the block() call or {% block %} tag.
2. Define the missing block in the template or in a parent template.
3. If the block lives in another template, use {% extends %}, {% use %}, or the two-argument block('name', 'other.twig') form.
4. Verify the template actually being rendered is the one you expect (check {% extends %} and include paths).

Example fix

{{ block('contnt') }}

{# after #}
{{ block('content') }}

$blocks = $twig->load('base.twig')->getSourceContext(); // or grep template source for '{% block name %}' before calling block('name')

try {
    return $twig->render('page.twig', $ctx);
} catch (\Twig\Error\RuntimeError $e) {
    if (str_contains($e->getMessage(), 'does not exist')) {
        return $fallbackTemplate;
    }
    throw $e;
}

When it happens

Trigger: Calling block('name') in a template/expression, block('name', template) via TemplateWrapper or Template::renderBlock, or yieldBlock() directly, where no template in the inheritance/trait chain defines 'name'.

Common situations: Typo in the block name inside a block() expression or function call; rendering a template directly that was meant to be included/extended; refactoring that renamed a block but not all references; calling block() before the defining template is loaded via {% extends %}/{% use %}.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

• Block " " on template " " does not exist.
• Block " " should not call parent() in " " as the block does…
• The "html_classes" function argument
• Failed to load Twig template
• The "cycle" function expects a non-empty sequence.

AI-assisted analysis of twigphp/Twig@a414c3a491 (2026-09-13). Data as JSON: /api/errors/7cf8922128e7ca03. Report an issue: GitHub.

Appendix: source

Thrown at src/Template.php:485

        // avoid RCEs when sandbox is enabled
        if (null !== $template && !$template instanceof self) {
            throw new \LogicException('A block must be a method on a \Twig\Template instance.');
        }

        if (null !== $template) {
            try {
                $template->ensureSecurityChecked();
                yield from $template->$block($context, $blocks);
            } catch (\Throwable $e) {
                $template->handleException($e);
            }
        } elseif ($parent = $this->getParent($context)) {
            yield from $parent->unwrap()->yieldBlock($name, $context, array_merge($this->blocks, $blocks), false, $templateContext ?? $this);
        } elseif (isset($blocks[$name])) {
            throw new RuntimeError(\sprintf('Block "%s" should not call parent() in "%s" as the block does not exist in the parent template "%s".', $name, $blocks[$name][0]->getTemplateName(), $this->getTemplateName()), -1, $blocks[$name][0]->getSourceContext());
        } else {
            throw new RuntimeError(\sprintf('Block "%s" on template "%s" does not exist.', $name, $this->getTemplateName()), -1, ($templateContext ?? $this)->getSourceContext());
        }
    }

    /**
     * Yields a parent block.
     *
     * This method is for internal use only and should never be called
     * directly.
     *
     * @param string $name    The block name to display from the parent
     * @param array  $context The context
     * @param array  $blocks  The current set of blocks
     *
     * @return iterable<scalar|\Stringable|null>
     */
    public function yieldParentBlock($name, array $context, array $blocks = []): iterable
    {
        if (isset($this->traits[$name])) {

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