1595980 - [jsdbg2] Forced return from an await onEnterFrame can cause a DebuggeeWouldRun exception

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect, P2)

Description

[Logan Smyth [:loganfsmyth]]

Test case:

let g = newGlobal({ newCompartment: true });
g.eval(`
  async function asyncFn(x) {
    await Promise.resolve();
  }
`);
const dbg = new Debugger(g);

(async function() {
  let it = g.asyncFn().catch(() => {});
  dbg.onEnterFrame = () => ({ return: "exit" });

  await it;

  dbg.onEnterFrame = undefined;
  g.asyncFn();
})();

I assume the forced return is queuing up the promise in microtask entry synchronously during the onEnterFrameHook where before it would have waited until after onEnterFrame completed.

Comment 1

[Logan Smyth [:loganfsmyth]]

Attachment: Bug 1595980 - Move return value adjustment into the debuggee scope. r=jimb!

Comment 2

[Jim Blandy :jimb]

Interesting: passing the shell --enable-experimental-await-fix makes this bug no longer occur.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

There's a r+ patch which didn't land and no activity in this bug for 2 weeks.
:loganfsmyth, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/042af67cea49
Move return value adjustment into the debuggee scope. r=jimb

Comment 5

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/042af67cea49