1253467 - Java-side JavascriptBridge will not receive messages from js if js.syncCall returns (including assertions)

Status: RESOLVED WONTFIX

(Firefox for Android Graveyard :: Testing, defect)

Description

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

So I can't:

Java---
js.syncCall('getPromiseValue');

JS---
function getPromiseValue() {
  aPromise().then(function (ret) {
    java.asyncCall('gotPromiseValue', ret);
  });
}

---
Either we should add to the documentation saying this is intended, or fix it.

Jim, is this expected?

Comment 1

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

Attachment: Code I was trying to write that found this bug

MozReview-Commit-ID: I1y2By9kVZm

Comment 2

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

To be more explicit with comment 0:

Java---
public void mainTest() {
  js.syncCall('getPromiseValue');
  spinAndWaitForJSCallToFinish();
}

public void gotPromiseValue(String ret) {
  // Never called.
}

public void spinAndWaitForJSCallToFinish() {
  // Do some Thread.sleep action in here until timeout
}

JS---
function getPromiseValue() {
  aPromise().then(function (ret) {
    java.asyncCall('gotPromiseValue', ret);
  });
}

I also replaced `java.asyncCall...` with `do_check_false(true)` and the test completed successfully, rather than failing as expected. It appears that all js -> java messages are ignored once js.syncCall returns. We can't use js.asyncCall because the test will return.

Comment 3

[(inactive) Jim Chen [:jchen] [:darchons]]

So your call will only go through if you wait for a call, which happens inside syncCall(). Otherwise, your test thread is busy doing other stuff (sleeping in this case), and the test thread doesn't get an opportunity to actually run the called method (because it's spending time inside Thread.sleep). If you put a dummy syncCall (e.g. js.syncCall("pollJs")) in the loop before you call Thread.sleep,  your async call should go through as well.

Comment 4

[(inactive) Jim Chen [:jchen] [:darchons]]

And if we want to "fix" this behavior, we should probably teach the JS side (i.e. JavaBridge) how to handle promises.

Comment 5

[Geoff Brown [:gbrown]]

Mass closing Firefox for Android :: Testing bugs with no progress in 2017.

If this bug is important to you, please re-open.