The above commit has to do with the experience a few of us had with rooms suddenly containing all new messages. There was no database corruption. THE DREADED AUTO-PURGER did this, and it appears to have believed that it was supposed to do that. When we purge `visit` records, we first build lists of valid users and rooms, and we delete any `visit` record that doesn't point to a valid user *and* a valid room.
I'm still not sure, but I think we built incomplete user and room lists in memory because of memory allocation. So now if we fail to allocate we crash the server completely. It's bad but losing data is worse. On another note, I think this happened on Uncensored because of the Brown Paper Bug that I fixed in the previous release.
