symfony/process · error · LogicException

Output cannot be disabled while an idle timeout is set.

Error message

Output cannot be disabled while an idle timeout is set.

What it means

disableOutput() throws this LogicException when an idle timeout has been configured. The idle timeout mechanism relies on reading process output to detect inactivity; with output disabled there is no read stream to monitor, so the two options are mutually exclusive and the library rejects the combination.

Solutions

Remove the setIdleTimeout() call if output must be disabled.
Keep the idle timeout and leave output enabled (do not call disableOutput()).
Use setTimeout() as a total-duration cap instead, which does not conflict with disabled output.

Example fix

// before
$process->setIdleTimeout(5.0);
$process->disableOutput(); // LogicException

// after
$process->setTimeout(30.0);
$process->disableOutput();

Defensive patterns

Strategy: validation

Validate before calling

if (null !== $timeout && $process instanceof \Symfony\Component\Process\Process) {
    // idle timeout requires output enabled: do not call disableOutput()
}

Try / catch

try {
    $process->disableOutput();
} catch (\LogicException $e) {
    // idle timeout is set; use setTimeout() instead or keep output enabled
}

Prevention

Treat idle timeout and disabled output as mutually exclusive in your config schema.
Prefer setTimeout() (wall-clock cap) when output is disabled.

When it happens

Trigger: Calling setIdleTimeout(...) followed by disableOutput(), or calling disableOutput() after setIdleTimeout() was set on the same Process instance.

Common situations: Developers hardening long-running subprocesses against hangs (adding an idle timeout) who also try to silence output for performance; configuration code setting both options independently.

Understand the failure class

Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

Related errors

AI-assisted analysis of symfony/process@99b85026db (2026-09-14). Data as JSON: /api/errors/26e1cb419afdd640. Report an issue: GitHub.

Appendix: source

Thrown at Process.php:594

        return $this;
    }

    /**
     * Disables fetching output and error output from the underlying process.
     *
     * @return $this
     *
     * @throws RuntimeException In case the process is already running
     * @throws LogicException   if an idle timeout is set
     */
    public function disableOutput(): static
    {
        if ($this->isRunning()) {
            throw new RuntimeException('Disabling output while the process is running is not possible.');
        }
        if (null !== $this->idleTimeout) {
            throw new LogicException('Output cannot be disabled while an idle timeout is set.');
        }

        $this->outputDisabled = true;

        return $this;
    }

    /**
     * Enables fetching output and error output from the underlying process.
     *
     * @return $this
     *
     * @throws RuntimeException In case the process is already running
     */
    public function enableOutput(): static
    {
        if ($this->isRunning()) {
            throw new RuntimeException('Enabling output while the process is running is not possible.');

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