Seldaek/monolog · error · InvalidArgumentException

$level is expected to be a string, int or {} instance

Error message

$level is expected to be a string, int or {} instance

What it means

Error "$level is expected to be a string, int or {} instance" thrown in Seldaek/monolog.

Source

Thrown at src/Monolog/Logger.php:571

        return $this->exceptionHandler;
    }

    /**
     * Adds a log record at an arbitrary level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param mixed             $level   The log level (a Monolog, PSR-3 or RFC 5424 level)
     * @param string|Stringable $message The log message
     * @param mixed[]           $context The log context
     *
     * @phpstan-param Level|LogLevel::* $level
     */
    public function log($level, string|\Stringable $message, array $context = []): void
    {
        if (!$level instanceof Level) {
            if (!\is_string($level) && !\is_int($level)) {
                throw new \InvalidArgumentException('$level is expected to be a string, int or '.Level::class.' instance');
            }

            if (isset(self::RFC_5424_LEVELS[$level])) {
                $level = self::RFC_5424_LEVELS[$level];
            }

            $level = static::toMonologLevel($level);
        }

        $this->addRecord($level, (string) $message, $context);
    }

    /**
     * Adds a log record at the DEBUG level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param string|Stringable $message The log message

View on GitHub (pinned to 57eb102834)

When it happens

Trigger: Thrown at src/Monolog/Logger.php:571 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/c30b13ee59f4b0a0. Report an issue: GitHub.