786576 - firefox 15 typeerror cant access dead object

Status: RESOLVED INVALID

(WebExtensions :: General, defect)

Description

[noitidart]

User Agent: Mozilla/5.0 (Windows NT 5.1; rv:15.0) Gecko/20100101 Firefox/15.0
Build ID: 20120824154833

Steps to reproduce:

I have this code in my addon which but FF 15 throws typerror cant access dead object. It works fine in all other versions and also i use this same technique in webpage development and it works error free.

This is the code:
		for (var i=0; i<this.stock.length; i++){
			for (var n in this.stock[i])	{
				bbstr += n+'='+this.stock[i][n]+'\n'; //this is the line that is highlighted by error console
			}
//..... theres more here
}


Actual results:

addon bugged out. error console threw error " typeerror cant access dead object"


Expected results:

it should have ran smoothly like in all other versions of firefox

Comment 1

[Ioana (away)]

[e-mail], can you please attach your add-on so I can try and reproduce the issue/confirm it?

Comment 2

[noitidart]

Ill get you a copy of my addon but the same error occurs in this addon here:
https://addons.mozilla.org/en-US/firefox/addon/floatnotes/?src=search

Thanks!

Comment 3

[noitidart]

Oh for the float notes you have to create a note on a site and then go back to the site and it wont show, but error console will have that error message. It worked fine till FF15.

Comment 4

[Ioana (away)]

(In reply to noitidart from comment #2)
> Ill get you a copy of my addon but the same error occurs in this addon here:
> https://addons.mozilla.org/en-US/firefox/addon/floatnotes/?src=search
> 
> Thanks!

Thanks for the link! I managed to reproduce the issue with this add-on on:
Mozilla/5.0 (Windows NT 6.1; rv:18.0) Gecko/18.0 Firefox/18.0 (20120902030516)

Comment 5

[Jorge Villalobos [:jorgev] (he/him)]

This means you're holding on to DOM references after the document has been destroyed. It is mentioned in this blog post: https://blog.mozilla.org/addons/2012/08/27/compatibility-for-firefox-15/

Comment 6

[noitidart]

Ah yes I am definitely doing that:
A: As.snapshotItem(i)

So can just read through it and if destroyed ignore it? Would I have to use try catch?

Comment 7

[Jorge Villalobos [:jorgev] (he/him)]

Ideally you should detect when the document is unloaded and then destroy the object yourself. Alternatively you could import the DOM object to a different document that doesn't depend on tabs. But I guess a try / catch could do the trick.

Comment 8

[Andrew McCreight [:mccr8]]

There's a new function to check if a window is destroyed, but I don't recall what it is called.

Comment 9

[Andrew McCreight [:mccr8]]

Also, it would probably be useful if there was an MDN article or something that contained this error message, and described how to fix it, including the new dead-proxy detection thing. I know there's a blog post, but a wiki article would be nice because then we could add things like the dead window detection.

Comment 10

[Justin Lebar (not reading bugmail)]

Components.utils.isDeadWrapper().

Comment 11

[noitidart]

Thank you all! I fixed my addon! I had stored this in an object:
var obj = {
A: As.snapshotItem(i),
//.....
}

so now Im just skipping over that after the page unloads.

Thanks again for your hard work! Firefox is becoming super!

Comment 12

[Justin Lebar (not reading bugmail)]

Can you please mark this bug as fixed once your fixed add-on gets approved in AMO?

Comment 13

[noitidart]

Oh sure thing! I'll mark it fixed right now, this is actually a personal addon.

Comment 14

[noitidart]

marking resolved