1337103 - Console should iterate through asyncParent frames of a stack trace

Status: RESOLVED DUPLICATE of bug 1530843

(DevTools :: Console, defect, P3)

Description

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

The stack gathering code in the console actor appears to ignore asyncParents:

http://searchfox.org/mozilla-central/rev/f5077ad52f8b90183e73038869f6140f0afbf427/devtools/server/actors/webconsole.js#1506

There may also be other places in DevTools where we're dropping this extra data.  We should comb other places where we loop through stack frames.

Comment 1

[Tom Tromey :tromey]

This worked ok in the simple case I tried.
Do you know how I can get this to do the wrong thing?

webconsole.js instantiates a StackTraceCollector, which does handle
async parents nicely; but I don't see this actually being used in that file.

Also Console.cpp creates a sequence of ConsoleStackEntry objects, dealing
with async parents internally.  Though I also don't think the code in
preparePageErrorForRemote is dealing with these either, since it is using
|.parent| rather than iterating over some kind of container.

Comment 2

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

(In reply to Tom Tromey :tromey from comment #1)
> This worked ok in the simple case I tried.
> Do you know how I can get this to do the wrong thing?

Here's an possible test case:

```
let bob = () => { setTimeout(function tom() { console.error(new Error()) }, 0) };
bob();
```

The console currently prints:

Error: 
Stack trace:
tom@debugger eval code:1:57

but it should be able to also list frames for the setTimeout and bob, if we traverse `asyncCaller`s.
 
> webconsole.js instantiates a StackTraceCollector, which does handle
> async parents nicely; but I don't see this actually being used in that file.

StackTraceCollector is used by the Net Monitor's tracking what triggered a request.  I think it's only appearing in webconsole.js because of the strange way that Net Monitor uses the console actors.

> Also Console.cpp creates a sequence of ConsoleStackEntry objects, dealing
> with async parents internally.  Though I also don't think the code in
> preparePageErrorForRemote is dealing with these either, since it is using
> |.parent| rather than iterating over some kind of container.

There appear to be many places we could be skipping this info, but it's a bit hard to search for:

http://searchfox.org/mozilla-central/search?q=.stack&case=true&regexp=false&path=devtools

As I understand it, here's an example of the correct looping to include this info:

http://searchfox.org/mozilla-central/rev/571c1fd0ba0617f83175ccc06ed6f3eb0a1a8b92/devtools/server/tests/unit/test_protocol_stack.js#85

One approach would be to centralize more of this into:

http://searchfox.org/mozilla-central/source/devtools/shared/platform/chrome/stack.js

which also seems to need updating.

Comment 3

[Nicolas Chevobbe [:nchevobbe]]

So, from the code linked before I don't think we look into asyncParent still, but the stacktrace shown for the code in Comment 2 do have the setTimeout information: 

tom         debugger eval code:1:47 
(Async: setTimeout handler) 
bob         debugger eval code:1:19 
<anonymous> debugger eval code:2:1

We should look at this more in detail to see if we have anything left to do or if we can close this.