`JS::Object#await` is unavailable inside Proc converted into JS closure

Open kateinoigakukun opened this issue 1 year ago • 0 comments

Reproducer

<html>
  <script src="https://cdn.jsdelivr.net/npm/@ruby/[email protected]/dist/browser.script.iife.js"></script>
  <script type="text/ruby" data-eval="async">
  require "js"

  JS.global.setTimeout(-> {
    JS.global[:Promise].resolve.await
  }, 0)
  </script>
</html>

browser.script.iife.js:2731 Uncaught Error: /bundle/gems/js-2.6.0/lib/js.rb:86:in `await': JS::Object#await can be called only from RubyVM#evalAsync or RbValue#callAsync JS API
If you are using browser.script.iife.js, please ensure that you specify `data-eval="async"` in your script tag
e.g. <script type="text/ruby" data-eval="async">puts :hello</script>
Or <script type="text/ruby" data-eval="async" src="path/to/script.rb"></script> (RuntimeError)
/bundle/gems/js-2.6.0/lib/js.rb:240:in `await'
eval_async:9:in `block in <main>'
    at checkStatusTag (browser.script.iife.js:2731:21)
    at browser.script.iife.js:2766:11
    at wrapRbOperation (browser.script.iife.js:2738:18)
    at callRbMethod (browser.script.iife.js:2764:14)
    at RbValue.call (browser.script.iife.js:2547:30)
    at browser.script.iife.js:2322:38

Workaround

Wrap the block with Fiber.new do ... end.transfer.

JS.global.setTimeout(-> {
  Fiber.new do
    JS.global[:Promise].resolve.await
  end.transfer
}, 0)

Solutions

We have several options to solve the issue

Always enter the body of Proc in Ruby with callAsync instead of call
- https://github.com/ruby/ruby.wasm/blob/dc9921a39c42cde001478622058531fc7ebf94e4/packages/npm-packages/ruby-wasm-wasi/src/vm.ts#L101C1-L106C9
- It's no use to manually choose whether call / callAsync and eval / evalAsync
Add conversion method to create an async version of JS function from proc.

e.g.

JS.global.setTimeout(JS.async do
  JS.global[:Promise].resolve.await
end, 0)

May 17 '24 07:05 kateinoigakukun