1468536 - Figure out what to do with Debugger.Object.global on CCWs

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Jan de Mooij [:jandem]]

Debugger.Object instances have a |global| property that returns the object's global, but with same-compartment realms, cross-compartment wrappers don't have a meaningful global (wrappers by shared by all realms in the compartment). See bug 1466112.

So question is what we want to happen here. Some options:

* Return |null| for D.O.global if the reference is a CCW.
* Throw an exception.
* Return a random global.
* ...

Comment 1

[Jan de Mooij [:jandem]]

(In reply to Jan de Mooij [:jandem] from comment #0)
> (wrappers by shared

*are* shared

> * Return |null| for D.O.global if the reference is a CCW.

*referent

That's what I get for filing bug reports while listening to a talk.

Comment 2

[Jim Blandy :jimb]

It seems to me that leaving behind compartment-per-global means that there really is no clear association between JSObjects (of all kinds) and globals any more. So perhaps that accessor is not meaningful.

I don't actually see the Debugger.Object.prototype.global accessor being used in devtools/server/actors. Even if it were, I'd still tend towards deleting it, because any code that uses it needs to be updated anyway.

Comment 3

[Jan de Mooij [:jandem]]

(In reply to Jim Blandy :jimb from comment #2)
> I don't actually see the Debugger.Object.prototype.global accessor being
> used in devtools/server/actors

It's used here:

https://searchfox.org/mozilla-central/rev/ed2763bea882619ccb48b0aecc54e523d2bdd2ae/devtools/server/actors/webconsole.js#1407

I *think* this is the only consumer (based on Try-servering a patch to dump the JS stack before MOZ_CRASH'ing).

What do you think about removing that ".global !== dbgWindow" check and always calling adoptDebuggeeValue?

Comment 4

[Jim Blandy :jimb]

Yes, it's a no-op in that case, so that should be fine.

Comment 5

[Jan de Mooij [:jandem]]

Attachment: Remove Debugger.Object.prototype.global

Comment 6

[Jim Blandy :jimb]

Comment on attachment 8989361 [details] [diff] [review]
Remove Debugger.Object.prototype.global

Review of attachment 8989361 [details] [diff] [review]:
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Thanks!

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/e378e29a5ebb
Remove Debugger.Object.prototype.global. r=jimb

Comment 8

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/e378e29a5ebb