I am recording this here only so that I don’t lose the information. My forum has been running for about a month and I have never had an issue logging out. Today only, one time, I logged out and got this error:

bbPress database error: [You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near 'LIMIT 1' at line 1]

SELECT * FROM bbpress_online WHERE user_id = LIMIT 1

Warning: Cannot modify header information - headers already sent by (output started at /htdocs/riverside/forum/bb-includes/db-mysqli.php:147) in /htdocs/riverside/forum/bb-includes/pluggable.php on line 168

This the the URL from the address bar:

http://www.example.com/forum/bb-login.php?logout

I’ve never had that before and I cannot reproduce it. It happened only once and is now fine. I had not edited any files in the past couple of days or added any new plugins. The only thing possibly related is I upgraded from Firefox 1.5.0.x to 2.0.0.1 yesterday, and this was the first time logging out on this computer with that browser (Windows XP if it matters.) Maybe that’s somehow related?

[chrishajerParticipant @chrishajer 6 years, 5 months ago]

This just happened again and I know why it happened now. This was with Firefox 2.0.0.1 on XP and Linux (I was able to reproduce it.) Open two windows or two tabs, with your forum loaded. Log out in one tab. Go the the other tab, now try to log out again (since, without a refresh, it still says you’re logged in, but you’re really not.) That’s when this error occurs.

You can also create it by entered this in your address bar when you are not logged into the forum.

http://www.mysite.org/forum/bb-login.php?logout

The first part, not being dumb, I can see, but with this “specially crafted URL” (ha ha) it should not error. The software should check if you’re logged in before attempting to log you out.