fix: transferrable not being transferred

[Deivu]

I noticed that returning a Transferable objects from a worker doesn't get the object transferred, instead it's being cloned.

To verify this, I created my own Implementation of Transferrable

class Shared {
    constructor({ ok, time, data } = {}) {
        this.ok = ok;
        this.time = time;
        this.data = data;
    }

    get [Piscina.transferableSymbol]() {
        return [this.data];
    }

    get [Piscina.valueSymbol]() {
        return { ok: this.ok, time: this.time, data: this.data };
    }

    make() {
        return Piscina.move(this);
    }
}

module.exports = Shared;

Then logged my buffer's byteLength intially, then after 1 second.

Without this fix, the byteLength didn't change, which signifies the buffer was not transferred

With the fix, the byteLength did change, which signifies the buffer was transferred

[addaleax]

@Deivu Is this something that you could add a test for?

[Deivu]

@addaleax Took me some time to get the test working, but I did manage to add a test for it

[arielszn]

Hey, we tried using the Piscina.move() feature for transferring a big object we need to deserialise on a worker thread, and then again a Piscina.move() from the worker thread to transfer back the deserialised object to the main thread, but this is not impacting on memory usage and latency as we were expecting for this change, we think it's not behaving as expected because of the issue that @Deivu is solving here.
Do you plan to merge this soon?

[jasnell]

Hmm looks like we've got a CI problem. I'll have to investigate that this weekend

[sogame]

Hi @jasnell, I'm also interested in this fix for my project, any luck with the CI issues? 😬

[arielszn]

Hey, we tried using the Piscina.move() feature for transferring a big object we need to deserialise on a worker thread, and then again a Piscina.move() from the worker thread to transfer back the deserialised object to the main thread, but this is not impacting on memory usage and latency as we were expecting for this change, we think it's not behaving as expected because of the issue that @Deivu is solving here. Do you plan to merge this soon?

Hey, any news over here :) ?

[nicholas-l]

Hey all, I have identified the issue with CI and have created a quick fix: #161

[sogame]

Hi @Deivu, now that the CI issue has been solved (in #161), could you update your branch with master, so the new build is triggered? 😇

[sogame]

Hi @jasnell would it be possible to get this fix merged (and even release a new version of piscina with it), please? 😇
Really looking forward to test my project with this improvement 🚀

[jasnell]

Running CI now, let's see where that lands first!

[jasnell]

merged! I'll look at cutting a new release tomorrow afternoon