352524 - [SessionStore] Exception when History menu clicked while SessionStore disabled

Status: RESOLVED DUPLICATE of bug 345898

(Firefox :: Session Restore, defect)

Description

[IU]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1b2) Gecko/20060913 BonEcho/2.0b2
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1b2) Gecko/20060913 BonEcho/2.0b2

If you click the History menu when using the Session Manager extension (0.4.3), the following JavaScript exception is thrown:

Error: '[JavaScript Error: "this._windows[aWindow.__SSi] has no properties" {file: "file:///C:/Program%20Files/Bon%20Echo/components/nsSessionStore.js" line: 648}]' when calling method: [nsISessionStore::getClosedTabCount] = NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS
Source file: chrome://browser/content/browser.js
Line: 6333


Reproducible: Always

Steps to Reproduce:
1. Install Session Manager 0.4.3 extension and restart
2. Open Error Console
3. Click History menu and note the exception

Actual Results:  
Aforementioned JavaScript exception is thrown.

Comment 1

[Simon Bünzli]

Note that you can replace step 1 above with:
1. Set the boolean pref browser.sessionstore.enabled to false.

The reason for the error is a missing check for whether SessionStore is actually enabled. The question is however: should callers have to check this (may lead to much duplicate code) or should getClosedTabCount et al. simply return 0/null/whatever instead of throwing? I'd favor the latter...

See also bug 345898 which is about making this error message more informative.

Comment 2

[Dietrich Ayala (:dietrich)]

Patch in bug 345898 fixes this.

Comment 3

[Simon Bünzli]

Still happens on the latest Trunk nightlies, so not WORKSFORME but at best a DUPE.