symfony/http-kernel · error · LogicException

Rendering a fragment can only be done when handling a…

Error message

Rendering a fragment can only be done when handling a Request.

What it means

FragmentHandler::render() throws LogicException when the request stack has no current Request. Fragment rendering works by issuing a sub-request derived from the master request, so it is meaningless outside of an HTTP request lifecycle (e.g. CLI commands, workers).

Solutions

Only render fragments within the request/response cycle.
In tests, push a Request: $requestStack->push(new Request()) before calling render().
For CLI contexts, render the content another way or construct a fake master Request.

Example fix

// before (in a command)
$html = $handler->render('/_fragment/foo', 'inline');
// after (in a test/setup)
$requestStack->push(Request::create('/'));
$html = $handler->render('/_fragment/foo', 'inline');

Defensive patterns

Strategy: validation

Validate before calling

if (null === $requestStack->getCurrentRequest()) { throw new \LogicException('No active request; cannot render fragments.'); }

Try / catch

try { $html = $handler->render($uri, 'inline'); } catch (\LogicException $e) { $html = ''; }

Prevention

Only call fragment APIs inside controller/kernel request scope
Guard CLI code paths explicitly
In tests, push a Request onto the stack in setUp

When it happens

Trigger: Calling render() from a console command, queue worker, or during kernel.boot before any request is pushed onto the RequestStack.

Common situations: Rendering fragments in CLI-generated emails, cache warmers, or tests that forgot to push a Request onto the stack.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of symfony/http-kernel@aa3a39d728 (2026-09-13). Data as JSON: /api/errors/dd4f12a88fd3c5e7. Report an issue: GitHub.

Appendix: source

Thrown at Fragment/FragmentHandler.php:78

     * Available options:
     *
     *  * ignore_errors: true to return an empty string in case of an error
     *
     * @throws \InvalidArgumentException when the renderer does not exist
     * @throws \LogicException           when no main request is being handled
     */
    public function render(string|ControllerReference $uri, string $renderer = 'inline', array $options = []): ?string
    {
        if (!isset($options['ignore_errors'])) {
            $options['ignore_errors'] = !$this->debug;
        }

        if (!isset($this->renderers[$renderer])) {
            throw new \InvalidArgumentException(\sprintf('The "%s" renderer does not exist.', $renderer));
        }

        if (!$request = $this->requestStack->getCurrentRequest()) {
            throw new \LogicException('Rendering a fragment can only be done when handling a Request.');
        }

        return $this->deliver($this->renderers[$renderer]->render($uri, $request, $options));
    }

    /**
     * Delivers the Response as a string.
     *
     * When the Response is a StreamedResponse, the content is streamed immediately
     * instead of being returned.
     *
     * @return string|null The Response content or null when the Response is streamed
     *
     * @throws \RuntimeException when the Response is not successful
     */
    protected function deliver(Response $response): ?string
    {
        if (!$response->isSuccessful()) {

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