node:worker_threads doesn't support MessagePort in workerData

[bartlomieju]

Version: Deno 1.41.3

In #22815 we got rid of raciness in worker setup code, but unfortunately now it's not possible to pass MessagePort in workerData and transferList options.

Doing so results in BadResource error when one tries to use the port: #22911 (comment)

Ref #22911

[bartlomieju]

Minimal reproduction:

// worker.mjs
import {
  isMainThread,
  MessageChannel,
  parentPort,
  receiveMessageOnPort,
  Worker,
  workerData,
} from "node:worker_threads";

if (isMainThread) {
  const { port1: mainPort, port2: workerPort } = new MessageChannel();

  // This re-loads the current file inside a Worker instance.
  const w = new Worker(import.meta.filename, {
    workerData: { workerPort },
    transferList: [workerPort],
  });

  w.on("message", (data) => {
    console.log("message from worker", data);

    const msg = receiveMessageOnPort(mainPort).message;
    console.log("message on mainPort", msg);
    w.terminate();
  });

  w.postMessage("Hello from parent");
} else {
  console.log("Inside Worker!");
  parentPort.on("message", (msg) => {
    console.log("message from main", msg);
    parentPort.postMessage("Hello from worker on parentPort!");
    workerData.workerPort.postMessage("Hello from worker on workerPort!");
  });
}

$ node worker.mjs
Inside Worker!
message from worker Hello from worker on parentPort!
message on mainPort Hello from worker on workerPort!
message from main Hello from parent

$ deno run -A worker.mjs
Inside Worker!
# exits
# There's actually a BadResource error raised, but it's swallowed an never surfaced

# With some debug logs
$ ./target/debug/deno run -A worker.mjs
Inside Worker!
parentPort listener called message
before MessagePort.postMessage Error
    at MessagePort.postMessage (ext:deno_web/13_message_port.js:117:52)
    at file:///Users/ib/dev/deno/worker.mjs:32:27
    at _listener (node:worker_threads:456:9)
    at innerInvokeEventListeners (ext:deno_web/02_event.js:754:7)
    at invokeEventListeners (ext:deno_web/02_event.js:801:5)
    at dispatch (ext:deno_web/02_event.js:658:9)
    at dispatchEvent (ext:deno_web/02_event.js:1043:12)
    at pollForMessages (ext:runtime_main/js/99_main.js:313:7)
    at eventLoopTick (ext:core/01_core.js:169:7)
before MessagePort.postMessage op 4
before get in op_message_port_message
after get  in op_message_port_message CustomError {
    class: "BadResource",
    message: "Bad resource ID",
}
after worker thread loop
error: Uncaught (in worker "") BadResource: Bad resource ID
    workerData.workerPort.postMessage("Hello from worker on workerPort!");
                          ^
    at MessagePort.postMessage (ext:deno_web/13_message_port.js:148:5)
    at file:///Users/ib/dev/deno/worker.mjs:32:27
    at _listener (node:worker_threads:456:9)
    at innerInvokeEventListeners (ext:deno_web/02_event.js:754:7)
    at invokeEventListeners (ext:deno_web/02_event.js:801:5)
    at dispatch (ext:deno_web/02_event.js:658:9)
    at dispatchEvent (ext:deno_web/02_event.js:1043:12)
    at pollForMessages (ext:runtime_main/js/99_main.js:313:7)
    at eventLoopTick (ext:core/01_core.js:169:7)
error: Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'message')
    const msg = receiveMessageOnPort(mainPort).message;
                                              ^
    at NodeWorker.<anonymous> (file:///Users/ib/dev/deno/worker.mjs:22:47)
    at NodeWorker.emit (ext:deno_node/_events.mjs:383:28)
    at NodeWorker.#pollMessages (node:worker_threads:310:12)
    at eventLoopTick (ext:core/01_core.js:169:7)