Seldaek/monolog · error · UnexpectedValueException

The nested handler of type ${class} does not support formatt

Error message

The nested handler of type ${class} does not support formatters.

What it means

Error "The nested handler of type ${class} does not support formatters." thrown in Seldaek/monolog.

Source

Thrown at src/Monolog/Handler/BufferHandler.php:151

        $this->resetProcessors();

        if ($this->handler instanceof ResettableInterface) {
            $this->handler->reset();
        }
    }

    /**
     * @inheritDoc
     */
    public function setFormatter(FormatterInterface $formatter): HandlerInterface
    {
        if ($this->handler instanceof FormattableHandlerInterface) {
            $this->handler->setFormatter($formatter);

            return $this;
        }

        throw new \UnexpectedValueException('The nested handler of type '.\get_class($this->handler).' does not support formatters.');
    }

    /**
     * @inheritDoc
     */
    public function getFormatter(): FormatterInterface
    {
        if ($this->handler instanceof FormattableHandlerInterface) {
            return $this->handler->getFormatter();
        }

        throw new \UnexpectedValueException('The nested handler of type '.\get_class($this->handler).' does not support formatters.');
    }

    public function setHandler(HandlerInterface $handler): void
    {
        $this->handler = $handler;
    }

View on GitHub (pinned to 57eb102834)

When it happens

Trigger: Thrown at src/Monolog/Handler/BufferHandler.php:151 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/051420af8bc85e97. Report an issue: GitHub.