Technically, Fossil didn't destroy the code; Zed destroyed it by running `fossil revert`. All Fossil did was run off into la la land where nothing makes sense and everything is invisible and the working directory is empty.

Still an impressive bug – but the first rule of “my CVS has broken” is “stop running commands, and copy the CVS directory somewhere else”. (I've needed to do this to a .git twice.) Had he done this, he wouldn't've lost work. While he shouldn't've had to, “stop doing everything and take a read-only copy” is the first step when any database containing important data has corrupted.