Seldaek/monolog · error · UnexpectedValueException

Errors while writing to process: %s

Error message

Errors while writing to process: %s

What it means

Error "Errors while writing to process: %s" thrown in Seldaek/monolog.

Source

Thrown at src/Monolog/Handler/ProcessHandler.php:93

        $this->command = $command;
        $this->cwd = $cwd;
        $this->timeout = $timeout;
    }

    /**
     * Writes the record down to the log of the implementing handler
     *
     * @throws \UnexpectedValueException
     */
    protected function write(LogRecord $record): void
    {
        $this->ensureProcessIsStarted();

        $this->writeProcessInput($record->formatted);

        $errors = $this->readProcessErrors();
        if ($errors !== '') {
            throw new \UnexpectedValueException(sprintf('Errors while writing to process: %s', $errors));
        }
    }

    /**
     * Makes sure that the process is actually started, and if not, starts it,
     * assigns the stream pipes, and handles startup errors, if any.
     */
    private function ensureProcessIsStarted(): void
    {
        if (\is_resource($this->process) === false) {
            $this->startProcess();

            $this->handleStartupErrors();
        }
    }

    /**
     * Starts the actual process and sets all streams to non-blocking.

View on GitHub (pinned to 57eb102834)

When it happens

Trigger: Thrown at src/Monolog/Handler/ProcessHandler.php:93 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/819bf25d180191c6. Report an issue: GitHub.