SerializationException when funnelling back to the main process fails to be serialized

[bwoebi]

Using zend.exception_ignore_args=0 (default)

parallel/src/Worker/Internal/task-runner.php

Lines 76 to 81 in 6bcfa22

	try {
	$channel->send($result);
	} catch (SerializationException $exception) {
	// Could not serialize task result.
	$channel->send(new Internal\TaskFailure($id, $exception));
	}

Whenever a $result fails to be serialized, an exception is thrown, which will include the arguments including $result in the serialization. Which then again fails to serialize, leading to the whole runner process blowing up.

There's a couple possibilities I see to solve this:
a) Force zend.exception_ignore_args=1 in the worker process.
b) Sanitize any sent Throwable's collected arguments from non-serializables.
c) Send exceptions as strings instead of serialized objects.

In my concrete use case it was caused by an exception thrown by the parallel mode of amphp/file - which was attempted to be serialized and contained some DeferredCancellation in the stacktrace.