symfony/process · error · LogicException

Idle timeout cannot be set while the output is disabled.

Error message

Idle timeout cannot be set while the output is disabled.

What it means

setIdleTimeout() throws this LogicException when a non-null timeout is requested while process output is disabled. Idle-timeout detection works by monitoring output reads; with output disabled there is nothing to observe, so the feature cannot function and the combination is rejected.

Solutions

Re-enable output (enableOutput()) before setting the idle timeout.
Use setTimeout() (total runtime cap) instead of an idle timeout.
Order the calls: setIdleTimeout() first, then disableOutput() is itself rejected too — so drop one of the two options.

Example fix

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

// after
$process->setIdleTimeout(5.0); // keep output enabled
$process->start();

Defensive patterns

Strategy: validation

Validate before calling

if (null !== $timeout && $idleTimeoutDesired) {
    // keep output enabled; skip disableOutput() and call setIdleTimeout() before start()
}

Try / catch

try {
    $process->setIdleTimeout($timeout);
} catch (\LogicException $e) {
    $process->setTimeout($timeout); // fall back to total-time cap
}

Prevention

Enforce in config validation: idleTimeout implies output enabled.
Order setters: setIdleTimeout() first in the builder and assert output stays enabled.

When it happens

Trigger: Calling setIdleTimeout(float) after disableOutput() was called (outputDisabled === true). Passing null is allowed.

Common situations: Silencing output for a noisy subprocess then later adding a hang-protection idle timeout; configuration assembled from separate flags that independently enable disableOutput and setIdleTimeout.

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/3b43616f2d423a95. Report an issue: GitHub.

Appendix: source

Thrown at Process.php:1065

        $this->timeout = $this->validateTimeout($timeout);

        return $this;
    }

    /**
     * Sets the process idle timeout (max. time since last output) in seconds.
     *
     * To disable the timeout, set this value to null.
     *
     * @return $this
     *
     * @throws LogicException           if the output is disabled
     * @throws InvalidArgumentException if the timeout is negative
     */
    public function setIdleTimeout(?float $timeout): static
    {
        if (null !== $timeout && $this->outputDisabled) {
            throw new LogicException('Idle timeout cannot be set while the output is disabled.');
        }

        $this->idleTimeout = $this->validateTimeout($timeout);

        return $this;
    }

    /**
     * Enables or disables the TTY mode.
     *
     * @return $this
     *
     * @throws RuntimeException In case the TTY mode is not supported
     */
    public function setTty(bool $tty): static
    {
        if ('\\' === \DIRECTORY_SEPARATOR && $tty) {
            throw new RuntimeException('TTY mode is not supported on Windows platform.');

View on GitHub (pinned to 99b85026db)