1240675 - Add tests for Bug 1208641

Status: RESOLVED FIXED

(Core :: General, defect)

Description

[Wei-Cheng Pan [:wcpan] [:wcp] [:legnaleurc] (left Mozilla)]

Add a test to ensure bug 1208641 do not fail.

Comment 1

[Wei-Cheng Pan [:wcpan] [:wcp] [:legnaleurc] (left Mozilla)]

An uncaught exception will cause the test fail, but unfortunately it's what I need to test.

Maybe we need something like "except_exception = MyException" in mochitest.

Comment 2

[Alexandre Poirot [:ochameau]]

I could help writing devtools test against that. Also I already wrote more low level test in xpconnect.
We already assert for valid stacks for common web exception.
In what precise scenarios should we see new stack appear on exceptions?

If I follow correctly, last patch from bug 1208641 is going to focus on window-related exceptions,
so it won't show JSM stacks yet?

Comment 3

[Wei-Cheng Pan [:wcpan] [:wcp] [:legnaleurc] (left Mozilla)]

(In reply to Alexandre Poirot [:ochameau] from comment #2)
> I could help writing devtools test against that. Also I already wrote more
> low level test in xpconnect.
> We already assert for valid stacks for common web exception.
> In what precise scenarios should we see new stack appear on exceptions?
>
> If I follow correctly, last patch from bug 1208641 is going to focus on
> window-related exceptions,
> so it won't show JSM stacks yet?

Yes, if a JSM throws an exception which created by Components.Exception, then the stack won't show in console.

I've tried to throw exception in the mochitest, but I can't seem to reproduce the problem.

Here is how I reproduce bug 1208641 on B2G:
1. modify some frequently used js module, e.g. BrowserElementParent.js
2. throw Components.Exception in every method
3. use adb logcat to observe B2G logs, some exceptions won't print the stack

Comment 4

[Boris Zbarsky [:bzbarsky]]

> An uncaught exception will cause the test fail, but unfortunately it's what I need to test.

SimpleTest.expectUncaughtException() will solve this problem for you.  But from inside a mochitest it may not be trivial to tell what the console sees, so a devtools test is likely better.

> In what precise scenarios should we see new stack appear on exceptions?

  <script>
  function f() {
    throw new DOMException("Hello");
  }
  f();
  </script>

Comment 5

[Alexandre Poirot [:ochameau]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=6ce83b078947

Comment 6

[Alexandre Poirot [:ochameau]]

Attachment: patch v1

Here is a patch varifying that stacks now appear on following code:
  document.querySelector("broken;selector");
  throw new DOMException("plop"); // <= may be this one is redundant?

Comment 7

[Alexandre Poirot [:ochameau]]

https://hg.mozilla.org/integration/fx-team/rev/138f7c7856b618dfd3f3faafcec9d3e164e188ec
Bug 1240675 - Verify that webconsole prints stacks for DOM Exceptions. r=vporof

Comment 8

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/138f7c7856b6