979189 - Debugger.Source.element should provide an Element instead of a plain object

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[Sebastian Zartner [:sebo]]

Referring to comment 37 and comment 49 of bug 935203.

The 'element' property of Debugger.Source should provide the owning element as normal DOM Element.

Sebastian

Comment 1

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

> Referring to comment 37 and comment 49 of bug 935203.
Proper links:
Referring to bug 935203 comment 37 and bug 935203 comment 49.

Honza

Comment 2

[Boris Zbarsky [:bzbarsky]]

How would that work when debugging cross-process?

Comment 3

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

(In reply to Boris Zbarsky [:bz] (reviews will be slow; ask someone else) from comment #2)
> How would that work when debugging cross-process?

Unless I am missing something, shouldn't the Debugger object and debugger server always be in the same process as the debuggee? Then we connect from the chrome/debugging process to the server via the remote debugging protocol.

See also https://bugzilla.mozilla.org/show_bug.cgi?id=937172

Comment 4

[Jim Blandy :jimb]

I *think* the issue here is simply that Debugger.Source.prototype.element is returning a Debugger.Object whose referent is the element. This seems to me like exactly what it should do. The tests were certainly written to expect this:

https://hg.mozilla.org/integration/mozilla-inbound/file/e2db166682ac/toolkit/devtools/server/tests/mochitest/test_Debugger.Source.prototype.element.html#l58

If you want the element, you can use Debugger.Object.prototype.unsafeDereference --- that is, src.element.unsafeDereference should indeed be an element.

I think this is a WONTFIX?

Comment 5

[Jim Blandy :jimb]

Wait, wait, I didn't mean to change the status --- if I'm misunderstanding the original poster, or if the approach I suggested doesn't work, then there's definitely something here to fix. Sorry.

Comment 6

[Sebastian Zartner [:sebo]]

Yes, that does the trick. Sorry for bothering you!

Sebastian

Comment 7

[Jim Blandy :jimb]

(In reply to Sebastian Zartner from comment #6)
> Yes, that does the trick. Sorry for bothering you!

No problem!

Debugger generally tries to preserve the "membrane" of Debugger.Blah instances protecting the debugger from the debuggee, except when you call functions whose explicit purpose is to pierce that membrane, like unsafeDereference.