Seldaek/monolog · error · RuntimeException

Failed to preg_split formatted string: {pcreErrorCode} / {pr

Error message

Failed to preg_split formatted string: {pcreErrorCode} / {preg_last_error_msg}

What it means

Error "Failed to preg_split formatted string: {pcreErrorCode} / {preg_last_error_msg}" thrown in Seldaek/monolog.

Source

Thrown at src/Monolog/Handler/ErrorLogHandler.php:88

        return new LineFormatter('[%datetime%] %channel%.%level_name%: %message% %context% %extra%');
    }

    /**
     * @inheritDoc
     */
    protected function write(LogRecord $record): void
    {
        if (!$this->expandNewlines) {
            error_log((string) $record->formatted, $this->messageType);

            return;
        }

        $lines = preg_split('{[\r\n]+}', (string) $record->formatted);
        if ($lines === false) {
            $pcreErrorCode = preg_last_error();

            throw new \RuntimeException('Failed to preg_split formatted string: ' . $pcreErrorCode . ' / '. preg_last_error_msg());
        }
        foreach ($lines as $line) {
            error_log($line, $this->messageType);
        }
    }
}

View on GitHub (pinned to 57eb102834)

When it happens

Trigger: Thrown at src/Monolog/Handler/ErrorLogHandler.php:88 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/5298a612821dacba. Report an issue: GitHub.