788148 - Script debugger doesn't show clientX and clientY properties for MouseEvent object

Status: RESOLVED FIXED

(DevTools :: Debugger, defect, P2)

Description

[Jan Honza Odvarko [:Honza] (always need-info? me)]

I don't see clientX and clientY props in the built-in debugger.

STR:
1) use the attached code snippet example
2) create a breakpoint on the console.log line
3) Break in the debugger
4) check the 'Function Scope' section and expand the 'Event' object
5) clientX and clientY are not there

function test(event)
{
    console.log(event);
}

<button onclick="test(event)">Click Me</button> 

Note that the properties are visible if the object is inspected using Web Console. 

Honza

Comment 1

[Panos Astithas (he/him) [:past] (please ni?)]

I've put your test code here:
http://htmlpad.org/native-desc/

The reason these properties don't show up is that Debugger.Object.getOwnPropertyDescriptor throws NS_ERROR_XPC_BAD_OP_ON_WN_PROTO:

http://mxr.mozilla.org/mozilla-central/source/toolkit/devtools/debugger/server/dbg-script-actors.js#1184

In the log I see this error for the following properties of MouseEvent: type,target,currentTarget,eventPhase,bubbles,cancelable,timeStamp,defaultPrevented,which,rangeParent,rangeOffset,pageX,pageY,isChar,screenX,screenY,mozMovementX,mozMovementY,clientX,clientY,ctrlKey,shiftKey,altKey,metaKey,button,buttons,relatedTarget,mozPressure,mozInputSource

I don't know the cause of this error or how to work around it, but hopefully Jim or Jason would have some ideas.

Comment 2

[Panos Astithas (he/him) [:past] (please ni?)]

This seems to be caused by bug 560072. It would be nice if we could come up with a workaround, because that bug doesn't seem easy to fix.

Comment 3

[Jim Blandy :jimb]

Note that bug 792215 will change the weird accessor properties on the prototype into ordinary accessor properties. The mouse events will still display as property-less objects whose prototypes have accessors on them, though, which is unfortunate.

It might be possible to use hostAnnotations to tell the debugger when to display such things. That's a proposed mechanism for objects' classes to give Debugger metadata about instances.

Draft spec for hostAnnotations:
https://github.com/jimblandy/DebuggerDocs/tree/onNewGlobal

Comment 4

[Panos Astithas (he/him) [:past] (please ni?)]

This *may* get fixed by bug 830818.

Comment 5

[Panos Astithas (he/him) [:past] (please ni?)]

(In reply to Panos Astithas [:past] from comment #4)
> This *may* get fixed by bug 830818.

Surprise, it didn't!
Bug 776864 is needed too, from what I can tell.

Comment 6

[Panos Astithas (he/him) [:past] (please ni?)]

(In reply to Panos Astithas [:past] from comment #5)
> (In reply to Panos Astithas [:past] from comment #4)
> > This *may* get fixed by bug 830818.
> 
> Surprise, it didn't!
> Bug 776864 is needed too, from what I can tell.

...or more accurately, bug 851073. Which was just fixed! \o/

Comment 7

[Victor Porof [:vporof][:vp]]

(In reply to Panos Astithas [:past] from comment #6)
> ...or more accurately, bug 851073. Which was just fixed! \o/

A million times \o/