Seldaek/monolog · error · InvalidArgumentException

The first argument of the GroupHandler must be an array of H

Error message

The first argument of the GroupHandler must be an array of HandlerInterface instances.

What it means

Error "The first argument of the GroupHandler must be an array of HandlerInterface instances." thrown in Seldaek/monolog.

Source

Thrown at src/Monolog/Handler/GroupHandler.php:41

class GroupHandler extends Handler implements ProcessableHandlerInterface, ResettableInterface
{
    use ProcessableHandlerTrait;

    /** @var HandlerInterface[] */
    protected array $handlers;
    protected bool $bubble;

    /**
     * @param HandlerInterface[] $handlers Array of Handlers.
     * @param bool               $bubble   Whether the messages that are handled can bubble up the stack or not
     *
     * @throws \InvalidArgumentException if an unsupported handler is set
     */
    public function __construct(array $handlers, bool $bubble = true)
    {
        foreach ($handlers as $handler) {
            if (!$handler instanceof HandlerInterface) {
                throw new \InvalidArgumentException('The first argument of the GroupHandler must be an array of HandlerInterface instances.');
            }
        }

        $this->handlers = $handlers;
        $this->bubble = $bubble;
    }

    /**
     * @inheritDoc
     */
    public function isHandling(LogRecord $record): bool
    {
        foreach ($this->handlers as $handler) {
            if ($handler->isHandling($record)) {
                return true;
            }
        }

View on GitHub (pinned to 57eb102834)

When it happens

Trigger: Thrown at src/Monolog/Handler/GroupHandler.php:41 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Seldaek/monolog@57eb102834 (2026-08-17). Data as JSON: /api/errors/a06470ca8029e58a. Report an issue: GitHub.