690374 - Session restore will delete the entire session data if Firefox is closed while restoring the session

Status: RESOLVED FIXED

(Firefox :: Session Restore, defect)

Description

[(no longer active)]

For a long time, my brother was complaining about Firefox sometimes failing to restore his old session.  He's using a somewhat old computer which restarts from time to time apparently because of a driver problem.  Today I finally managed to understand what happens to him, and here's the bug report.

What he has been experiencing is opening Firefox to about:sessionrestore, and clicking the Restore button, with his computer restarting shortly after, before the session restore operation finishes.  every time that it happens, when he starts Firefox after a reboot, his session is empty.

I think that what happens is when we start restoring the session, we somehow mess with sessionstore.js and leave it in an inconsistent state which causes future session restores to fail unless the current restore process finishes and we overwrite sessionstore.js again.

Paul, does that seem plausible?

Comment 1

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

I would need to look more closely, but if it's possible I think the time frame it would have to crash in is pretty small. As I know it, that feature was made to survive crashes during restore because we were expecting them. We never wipe out the file, the file starts with the full crashed state, then next write would be crash state open in about:sessionrestore, then next write after pressing "restore session" should contain the full session.

Perhaps if the crash happens while we're actually writing the file, it doesn't complete and leaves it in a broken state? (though I thought the file writing stuff wrote to a temp file and then moved it into place).

I'd suggest getting a copy of sessionstore.js/.bak next time that happens and see if the file is actually blank or in some broken state

Comment 2

[astabel]

for me this bug is slightly different:
I usually have 3 to 5 windows with several tabs and firefox takes a while to open these windows.
if my PC bluescreens while only 2 of these 4 windows are opened, the next time i almost assuredly have only those 2 windows left and the rest gone.

so it seems to me that this files is written before everything is restored.
Maybe that helps tracking this one.

Comment 3

[David Teller [:Yoric] - still alive but not very active]

Bug 887780 might fix this.

Comment 4

[Tim Taubert [:ttaubert] (inactive)]

This sounds a lot like bug 637020. I'm quite optimistic that it fixes this issue.

Comment 5

[Tim Taubert [:ttaubert] (inactive)]

Marking as fixed by bug 637020.