Promises do not work (WebAssembly.instantiate in particular)

[alexdoesh]

Looks like WebAssembly.instantiate(...).then(...).catch(...) can't be properly evaluated due to lack of microtasks processing and message pumping in eval methods. I see a bunch of examples how to implement this in the old v8 versions, but can't understand yet what to do in 10.x, the API was changed significantly. Any chance you can advice how to proceed?

[alexdoesh]

I "brute forced" a solution for my case -> #47 + a wrapper like this:

context.eval("""
var instance = null;
WebAssembly.instantiate(moduleRaw, {}).then(result => {
    instance = result.instance;
}).catch(result => {
    instance = result.message;
});""")
while context.eval('instance === null'):  # covered with timeout in production
    pass

[buffer]

Thanks!

The approach looks really interesting and it is definitely worth exploring. I enabled the tests for your PR and it seems like your code is passing all the existing ones. I think that creating some additional unit tests that focus just on your patch is probably another useful step we should consider. Once we have that in place I will take care of performing an additional check running Thug [1] unit test suite using your branch. This unit test suite is way more extensive than the STPyV8 one and could help spotting potential issues if any.

[1] https://github.com/buffer/thug