Deno: Deno Worker memory leak

[highmountaintea]

I have a simple main / worker messaging demo that consumes memory continuously. The below sample will consume > 1GB after 10 minutes.

OS: Windows 10
Env: VMWare VM with 4 virtual procs and 32 GB RAM
Deno 1.1.0

to run: deno run --allow-read parent.js

parent.js

let worker = new Worker(new URL("worker.js", import.meta.url).href, { type: "module" });

let struct = {
  headers: ["database", 1, 2],
  value: 1
};

worker.postMessage(struct);

worker.onmessage = async (e) => {
  let { got, hit } = e.data;
  if (hit) console.log("hit: " + got);
  struct.value = got + 1;
  worker.postMessage(struct);
};

worker.js

let expected = 12345;

let struct = {
  got: null,
  hit: null,
};

self.onmessage = async (e) => {
  const { value } = e.data;
  if (value % 10000 === 0) console.log(value);
  struct.got = value;
  struct.hit = value === expected;
  postMessage(struct);
};

[highmountaintea]

I performed more tests to see if the bug is OS specific or is a regression bug. The following environments all exhibit the same issue:

OS: Windows 10
Env: Intel i7-8550U laptop with 16GB RAM
Deno 1.1.0

OS: Ubuntu 19.10
Env: Intel Atom x5-Z8350 laptop with 4GB RAM
Deno 1.1.0

OS: Windows 10
Env: Intel i7-8550U laptop with 16GB RAM
Deno 1.0.2

[wongjiahau]

I'm also able to replicate this on macOS, I think it might be related to this issue. But fortunately the memory will be freed once the worker is terminated via invoking worker.terminate().