This bug is similar to the one mentioned under <a href="tktview?name=c7b35be884">c7b35be884</a>. Here Fossil allow to add a repository db (that is contained in the same directory tree as the checkout) to itself like this:
<pre>
  mkdir test1
  cd test1
  fossil new myrepo
  fossil open myrepo
  fossil add myrepo
  fossil commit
  fossil commit
  :
</pre>
ad infinitum. In spririt of the commands <tt>clean</tt> and <tt>extra</tt> Fossil should not allow to add its own repository database to itself.