574714 - Sessionstore not clearing completly on clean browser exit; giving false restore session alert

Status: RESOLVED INCOMPLETE

(Firefox :: Session Restore, defect)

Description

[Emm]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.4) Gecko/20100611 Firefox/3.6.4
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.4) Gecko/20100611 Firefox/3.6.4

A problem in the sessionstore engine which allows the session store file (sessionstore.js) to be kept on clean exists, thus crating problems like a never-shrinking/always-growing sessionstore.js file, false notices of restoring past session.

Reproducible: Sometimes

Steps to Reproduce:
1a.Optionally: under Tools > Options > General tab > When Firefox starts: set it to Show my windows and tabs from last time.
1b.Optionally but advised, in about:config set browser.sessionstore.max_tabs_undo to 30 or higher and browser.sessionstore.postdata to 1. This will cause the sessionstore.js to get bigger faster.
2.Browse heavily. Most notably facebook and youtube on long sessions, these two sites have shown to be taken seriously by the sessionstore engine, the js file growing a lot. I haven't managed to make more than a 3 MB sessionstore.js file but who knows.
3.Close all tabs, leave only the one blank tab.
4.Close the browser and wait until it terminates itself, sometimes it takes a few seconds.
Actual Results:  
Since the last tab was a blank tab, the session store engine would not need to store anything and the sessionstore.js file should be deleted as it is the case explained by in the note below. It is not deleted! And this causes one of two problems:

1. If Firefox finds an error (screen will be posted later) a window is displayed asking the user to restore the previous session, which in fact was a blank tab, so there's nothing to restore. Well, not quite... it restores some of the tabs active prior to their closure and replacement by the one blank tab.

2. If no. 1 doesn't trigger, sessionstore continue to use the same sessionstore.js file, growing without the need to, creating mixed or dirty sessions, preserving data which might be sensitive even if the used explicitly denied this by leaving just the clean tab at the end of the session. This ever-growing file also makes paying youtube videos (and not only) as well as other sites with plain HTML/JS content and general interactivity with the browser jitter every 10 seconds, supposedly when Firefox dumps the json in the file on the disk. It won't be noticeable if the profile or the sessionstore.js file itself is on a ram drive or an SSD but it will create this unwanted behavior on a regular HDD.

Expected Results:  
The sessionstore.js file should be deleted or cleaned otherwise from tabs that were closed/terminated prior closing the browser and the history should not be kept unless the sessionstore engine resumed from a crash or an actual session left by the user (tabs and windows open, etc).

Note: this I just found pout today, thus I could write this bug report.
The behavior doesn't show if the option When Firefox starts: in General tab is set to show a blank page. I  this case, after each termination of the browser, the file sessionstore.js is actually deleted and when rerunning the application the session is clean and the browser doesn't experience any more "oops"es and messages like that.

I know that the workaround would be to just disable saving of tabs upon closing the browser, but that would defeat the purpose of its functionality, which is a needed feature.

Comment 1

[Paul O'Shannessy [:zpao] (not bugmail, email directly)]

So you want Firefox to save your session UNLESS that session ends with a blank tab? (note: "session" includes closed windows & tabs, cookies, etc.) As you've noticed, that's not how it works. We'll continue to save those closed windows & tabs.

This sounds familiar so we probably have a bug about it.

(In reply to comment #0)
> I know that the workaround would be to just disable saving of tabs upon closing
> the browser, but that would defeat the purpose of its functionality, which is a
> needed feature.

I've set Firefox to show a blank tab at startup & just save my session when quitting by saying "save session" in the dialog that asks.

Comment 2

[Emm]

I'm talking about the difference in behaviors with "blank page start-up" and "show tabs from last time".

In the "blank tab" one, Firefox uses sessionstore in case of crashes and undo functionality. But if I close Firefox, the sessionstore.js file gets deleted.

In the "show tabs from last time" one, Firefox saves the sessionstore.js file every time, even if there was nothing to save, and if it has data it remains dirty at start-up, triggering either:
- restoration of past opened windows and tabs even if before I closed the browser I closed every tab and window. It's not a pretty site... once I got 8 windows and about 200 tabs opened at start-up, never-mind that I had to taskkill it and delete the sessionstore.js file manually. -
- that "Well, this is embarrassing" page (http://www.blogsdna.com/wp-content/uploads/2009/08/restore-session-firefox-35.png) also accessible from about:sessionrestore... often.

Also as an adverse effect, the file in question doesn't get cleaned if it gets heavy, i.e. it keeps growing, while in "show blank page mode" it shrinks preventing the I/O lag issue while browsing.

What would have been proper is to have sessionstore engine clear the sessionstore.js file if the browser closes clean, one blank tab, when it's set up to start the way mentioned above since it has nothing to save.

This was a problem that plagued me for a long time on 3.5.9 and I didn't knew why. I upgraded to 3.6.4, tested out the sessionstore engine but the thing that I didn't do was to close the browser with active tabs and select "do not ask next time" box in the closing message box about saving tabs. In 3.5 I did and it remained in saving mode. Of course now I figured it and I leave that message appear only when I need to save tabs, which kinda fixes functionality at the expense of that one message and choice each time I need it instead of doing it automatically.

Comment 3

[malcolmtaylor123]

Since updating firefox to 23.0.1, I keep getting the session restore message asking me to restore last session every time I restart Firefox even though it closed properly. Very annoying because I like to keep some of my tabs. Definitely new since version 23. Come on guys have a look, there must be more out there with same problem.

Comment 4

[...]

Yup there is seriously something screwed up with sessionstore lately. I keep getting corrupt sessions (1KB). Very frequent crashes under heavy load, and when restoring sessions they aren't up to date. The session file keeps growing in size. Attempts to save sessions in Session Manager shows empty tabs. There are error messages saying OUT_OF_MEMORY, stack is undefined and other pointless jargon. Constant crashing leads to a 10MB sessionfile. It might just be my session file is no longer usuable, but I'm sure something could be done?

Comment 5

[Wayne Mery (:wsmwk)]

Jim reports privately that he is no longer using Firefox.  Given the gap between comment 2 and 3 I think it makes sense to close this incomplete.

malcolmtaylor123, if you still see a problem when using the newest version , please file a new bug.


(In reply to ... from comment #4)
> Yup there is seriously something screwed up with sessionstore lately. 
you are in the wrong bug, because a *new* issue would not be this *old* bug (if it is still a bug).  And if you are getting OOM all bets are off.  Probably because of hundreds of tabs?