sebastianbergmann/phpunit · error · ParameterDoesNotExistException

Parameter "%s" does not exist

Error message

Parameter "%s" does not exist

What it means

Runner extensions receive a ParameterCollection built from the <parameter name="..." value="..."/> child elements of the extension's <bootstrap> block in phpunit.xml. get(string $name) throws ParameterDoesNotExistException(sprintf('Parameter "%s" does not exist', $name)) when no parameter with exactly that name was configured. The sibling method has(string $name) is the safe boolean check.

Source

Thrown at src/Runner/Extension/ParameterCollection.php:54

     * @param array<string, string> $parameters
     */
    private function __construct(array $parameters)
    {
        $this->parameters = $parameters;
    }

    public function has(string $name): bool
    {
        return array_key_exists($name, $this->parameters);
    }

    /**
     * @throws ParameterDoesNotExistException
     */
    public function get(string $name): string
    {
        if (!array_key_exists($name, $this->parameters)) {
            throw new ParameterDoesNotExistException($name);
        }

        return $this->parameters[$name];
    }
}

View on GitHub (pinned to f123cdb2a2)

Solutions

1. Add the missing parameter in phpunit.xml inside the extension element: <bootstrap class="Vendor\MyExtension"><parameter name="foo" value="bar"/></bootstrap>.
2. Verify the exact name and casing used by the extension; the lookup is case-sensitive.
3. In extension code, guard with has() and provide your own default: $value = $parameters->has('foo') ? $parameters->get('foo') : 'default';

Example fix

<!-- before (phpunit.xml) -->
<extensions>
    <bootstrap class="Vendor\MyExtension"/>
</extensions>

<!-- after -->
<extensions>
    <bootstrap class="Vendor\MyExtension">
        <parameter name="apiKey" value="secret"/>
    </bootstrap>
</extensions>

// in extension bootstrap(), before any get() call
if (!$parameters->has('apiKey')) {
    throw new \RuntimeException(
        'MyExtension requires "apiKey": add <parameter name="apiKey" value="..."/> to the <bootstrap> element in phpunit.xml'
    );
}
$apiKey = $parameters->get('apiKey');

final class SafeParameters
{
    public function __construct(
        private readonly \PHPUnit\Runner\Extension\ParameterCollection $parameters,
    ) {
    }

    public function optional(string $name, string $default): string
    {
        return $this->parameters->has($name)
            ? $this->parameters->get($name)
            : $default;
    }
}

When it happens

Trigger: Calling $parameters->get('foo') in an extension's bootstrap() when phpunit.xml has no <parameter name="foo" .../> element for that extension, or when the code and XML names differ in spelling or case (the array_key_exists lookup is exact and case-sensitive).

Common situations: Typo between the XML attribute and the extension code; CI using a different phpunit.xml that lacks the parameter; upgrading an extension that renamed its parameters; forgetting that parameters must be strings and always present (no defaults exist at this layer).

Related errors

• Cannot load XML configuration file %s
• Invalid version comparison operator: "%s"
• The file does not validate against any known schema
• The file does not need to be migrated
• Default test suite is not configured

AI-assisted analysis of sebastianbergmann/phpunit@f123cdb2a2 (2026-08-23). Data as JSON: /api/errors/b012b26db9c08a3a. Report an issue: GitHub.