817425 - many id's in devtools debugger listed as undefined

Status: RESOLVED FIXED

(DevTools :: Debugger, defect)

Description

[mcdavis941 (sporadically reading bugmail)]

Looking at the DOM of the devtools debugger in DOM Inspector, with Firefox 19, it shows many of the debugger's own elements with id="undefined".  I'm sure you would have noticed by now if this were a problem, but it's still a little eyebrow-raising.

Screenshot to follow.

STR:
1 - Launch Firefox 19.
2 - Visit https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsIComponentManager .
3 - Open the debugger for that page.
4 - Select tabzilla.js, set a breakpoint on line 320, the first line of Tabzilla.toggle().
5 - Click the Tabzilla button (the big Mozilla button at the top of the content page) to trigger the breakpoint.
6 - Open DOM Inspector.
7 - Use DOM Inspector to inspect "this" under Function scope for Tabzilla.toggle in the right pane (variables).
8 - Expand the DOM tree in DOM Inspector, notice many elements have the same id ("undefined").

Comment 1

[mcdavis941 (sporadically reading bugmail)]

Attachment: screenshot

Comment 2

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

These are elements created dynamically. Why would they need to have an id?

Comment 3

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

Attachment: v1

Ah, I see what's happening here. It's the string "undefined", not an undefined value, which is bad. There was a typo in the node creation function. I fixed it and added a test to make sure this won't be an issue again.

Thanks for noticing this, mcdavis.

Comment 4

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

Comment on attachment 687550 [details] [diff] [review]
v1

Review of attachment 687550 [details] [diff] [review]:
-----------------------------------------------------------------

I guess the typo was that you added the underscore and didn't get the getter as a result, right?

Comment 5

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

(In reply to Panos Astithas [:past] from comment #4)
> Comment on attachment 687550 [details] [diff] [review]
> v1
> 
> Review of attachment 687550 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> I guess the typo was that you added the underscore and didn't get the getter
> as a result, right?

Yes. I'm just using the _idString property directly to avoid the getter, since it's part of the same prototype and we're not breaking any privacy conventions.

Comment 6

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

https://hg.mozilla.org/integration/fx-team/rev/c69c1d17aabe

Comment 7

[Rob Campbell [:rc] (:robcee)]

https://hg.mozilla.org/mozilla-central/rev/c69c1d17aabe