435194 - nsExtensionManager.js: item is a null pointer

Status: RESOLVED INCOMPLETE

(Toolkit :: Add-ons Manager, defect)

Description

[David Waring]

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9b5) Gecko/2008043010 Fedora/3.0-0.60.beta5.fc9 Firefox/3.0b5
Build Identifier: 1.9pre9

I noticed while trying to install extensions in Firefox 3b5 that the error console was reporting a problem of a null pointer in nsExtensionManager.js at line 3725. The extensions were also not showing up properly in the Add-ons dialog.

The problem is that the _getActiveItems function doesn't check that the allItems array doesn't contain null objects. I fixed this on my system by adding "if (item == null) continue;" just before line 3725 ("var installLocation = this.getInstallLocation(item.id);"). This allowed the Firefox Add-ons manager to function properly.

This may be indicative of a bigger problem, but this one line fix appears to sort the problem out.

Reproducible: Always

Steps to Reproduce:
1. In Firefox 3b5 open error console.
2. In Firefox 3b5 open Add-ons window.
Actual Results:  
Error message about item being a null pointer in the error console which refers to /usr/lib64/xulrunner-1.9pre9/components/nsExtensionManager.js line 3725.

Firefox indicates some extensions as disabled and fails to install new extensions.

Expected Results:  
No error message in error console, enabled extensions are indicated as such and add-on installs work.

This happened after an upgrade from Fedora 8 (firefox 2.0.0.14) to Fedora 9 (firefox 3 beta 5).

Comment 1

[Benjamin Smedberg]

FWIW, I see this all the time on all three of my machines. It didn't seem to hurt much, so I didn't go digging, but it's something we should fix. David, can you attach your changes as a patch?

Comment 2

[Dave Townsend [:mossop]]

FWIW there are changes related to errors like this since 3.0b5 that may have already fixed this, as well as changes waiting to land in bug 433371.

Comment 3

[David Waring]

Attachment: Checks the var "item" for being null, if null assumes that the item is not active.

After upgrading to Firefox 3.0 I still have the same problem. I've checked the CVS source and found that the var "item" is still not being checked for being null before getting used. I'm including a patch for this.

Comment 4

[Dave Townsend [:mossop]]

It would be better to make getItemList never return nulls, and even better to understand what problem is causing it to in the first place.

Comment 5

[Dave Townsend [:mossop]]

This code is gone and the problem was never understood.