Watilin Reporter
	Description • 12 years ago

User Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/17.0 Firefox/17.0
Build ID: 20120805030518

Steps to reproduce:

(On Nightly 17.0a1 with a fresh profile)

On a page containing this script :

function F() { this.x = 1; }

I opened the web console and typed "new F()".


Actual results:

the console returned "undefined".


Expected results:

It should have returned "({x:1})".

However, when I type "new window.F()" I get the right result. This bug seems related to https://bugzilla.mozilla.org/show_bug.cgi?id=752404 although the latter have been resolved.

	Loic
	Comment 1 • 12 years ago

In the latest Nightly, if I type your instructions in the web console, I see:

--
[10:43:51.175] function F() { this.x = 1; }
[10:43:51.180] undefined
--
[10:43:56.231] new F()
[10:43:56.251] ({x:1})

	Watilin Reporter
	Comment 2 • 12 years ago

Of course it works when the constructor has been declared into the console.
I figured out it also works when the constructor is used inside another function declared into the page :

function createF() { return new F(); }

When typing "createF()" in the console, I get the correct "({x:1})". It seems that the "new" operator has trouble to work wih the global context.

	Watilin Reporter
	Comment 3 • 12 years ago

This page contains the declaration of functions "F" and "createF" to be used in the Web Console.

	Loic
	Comment 4 • 12 years ago

I followed your testcase and I found this regression range:

mozilla-central:
good=2012-07-14
bad=2012-07-15
changelog: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=0602e44ac248&tochange=57abb5f70e01

Suspected bug to confirm:
Boris Zbarsky — Bug 771429. Instead of using bound functions for the functions we get off the sandbox proto, use a function proxy. That allows property gets on the functions to get through. r=bholley

	Boris Zbarsky [:bzbarsky] Assignee
	Comment 5 • 12 years ago

This is totally a JS engine bug; I assumed that proxy construction actually worked correctly, but it very much doesn't.

	Boris Zbarsky [:bzbarsky] Assignee
	Comment 7 • 12 years ago

Requesting tracking for the regression.

	Eddy Bruel [:ejpbruel]
	Comment 9 • 12 years ago

Comment on attachment 650145 [details] [diff] [review]
Make construction via a function proxy with an object in the constructor slot actually construct instead of just calling.

Review of attachment 650145 [details] [diff] [review]:
-----------------------------------------------------------------

Looking good :-)

	Boris Zbarsky [:bzbarsky] Assignee
	Comment 10 • 12 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/a047c51aafd0

Eddy, how do you feel about taking this on branches?  Seems like we need to do this if we want to fix the web console behavior there....

	Boris Zbarsky [:bzbarsky] Assignee
	Comment 11 • 12 years ago

Comment on attachment 650145 [details] [diff] [review]
Make construction via a function proxy with an object in the constructor slot actually construct instead of just calling.

[Approval Request Comment]
Bug caused by (feature/regressing bug #): Bug 771429 
User impact if declined: Calling non-DOM constructors in the web console doesn't
   work right.
Testing completed (on m-c, etc.): Passes attached automated tests.
Risk to taking this patch (and alternatives if risky): I don't know.  Eddy is a
   better source for this.
String or UUID changes made by this patch: None.

	Ed Morley [:emorley]
	Comment 12 • 12 years ago

https://hg.mozilla.org/mozilla-central/rev/a047c51aafd0

	Boris Zbarsky [:bzbarsky] Assignee
	Comment 13 • 12 years ago

For what it's worth, Eddy thinks risk is low.

As far as alternatives if we decide this is too risky, I see several:

1)  Ship with this problem.
2)  Back out bug 771429 and ship with its problem instead of this one.
3)  Back out bug 771429 and fix it in some other way.  I'm not quite sure how, and it
    would almost certainly be riskier than this patch.
4)  Change the function proxy code so consumers can pick between the old and new behavior
    and only opt in sandboxes to the new behavior for now.  This is probably doable if
    really needed.  I think.

	Lukas Blakk [:lsblakk] use ?needinfo
	Comment 14 • 12 years ago

Comment on attachment 650145 [details] [diff] [review]
Make construction via a function proxy with an object in the constructor slot actually construct instead of just calling.

I think we're ok to not do a backout and to take this on branches.

	Joe Drew (not getting mail)
	Comment 15 • 12 years ago

This was pushed to aurora: https://hg.mozilla.org/releases/mozilla-aurora/rev/4cbf6aa4f022
and then backed out for making aurora orange. https://hg.mozilla.org/releases/mozilla-aurora/rev/c2d5393d005c

	Joe Drew (not getting mail)
	Comment 16 • 12 years ago

Similarly landed on beta: https://hg.mozilla.org/releases/mozilla-beta/rev/ad7dd2476dfe
and then backed out: https://hg.mozilla.org/releases/mozilla-beta/rev/aa331c131a65

	Joe Drew (not getting mail)
	Comment 17 • 12 years ago

Only partially landed on aurora:  https://hg.mozilla.org/releases/mozilla-aurora/rev/9211b0e0edad and hence backed out: https://hg.mozilla.org/releases/mozilla-aurora/rev/9211b0e0edad

	Eddy Bruel [:ejpbruel]
	Comment 18 • 12 years ago

Pushed to aurora:
https://hg.mozilla.org/releases/mozilla-aurora/rev/52956b3e7be2

Hopefully wont be backed out this time

	Eddy Bruel [:ejpbruel]
	Comment 19 • 12 years ago

And again to beta:
https://hg.mozilla.org/releases/mozilla-beta/rev/bc0a3117d9b4

	Eddy Bruel [:ejpbruel]
	Comment 20 • 12 years ago

D'oh

	Boris Zbarsky [:bzbarsky] Assignee
	Comment 21 • 12 years ago

For what it's worth, it looks like the first thing that got pushed was the old, obsolete, patch.  The one that didn't have approvals...

	Paul Silaghi, QA [:pauly]
	Comment 22 • 12 years ago

Able to see the issue on FF 15b4.
Verified fixed on FF 15b5 on Win XP and Win 7 using the STR in comment 0 and the testcase.
Removing verifyme for now. Please add again if you can think of any edge cases related to this that should be tested.

	Paul Silaghi, QA [:pauly]
	Comment 23 • 12 years ago

Verified fixed on:
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20100101 Firefox/16.0b4
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/17.0 Firefox/17.0 17.0a2 (2012-09-24)