[CF-Devel] Strange problem, possible related to new attack fixes (hit player)

[Jan Echternach]

On Thu, Nov 23, 2000 at 04:52:38PM -0800, Peter Mardahl wrote:
>
     
      I checked in a "fix" for this problem, but I think the bug is
     
     >
     
      actually somewhere else than I "fixed" it.
     
     
Oops, my bug.  And the bug really is in check_fired_arch().
hit_player() is allowed to do about anything.  hit_player() can trigger
runes, runes can summon monster, monster can pick up stuff, etc. pp.


>
     
                  if (was_destroyed (op, op_tag) || ! was_destroyed (tmp, tmp_tag)
     
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
>
     
                      || (op->stats.dam -= dam) < 0)
     
     >
     
                  {
     
     >
     
      	      if(!QUERY_FLAG(op,FLAG_REMOVED)) {   /* line ADDED */
     
     >
     
                      remove_ob (op);
     
                       ^^^^^^^^^^^^^^^
>
     
                      free_object(op);
     
     >
     
                      return;
     
     >
     
      	      }
     
     
Broken code (without the QUERY_FLAG) - if 'op' was already destroyed
(which means it was already freed), it will be removed and freed
again.

'op' may have been reused and therefore not have FLAG_REMOVED, even
though it's not the same object anymore.  Correct fix would be this:

            if (was_destroyed (op, op_tag))
                return;
            if ( ! was_destroyed (tmp, tmp_tag)
                || (op->stats.dam -= dam) < 0)
            {
                remove_ob (op);
                free_object(op);
                return;
	    }

Maybe remove_ob() and free_object() should just print an error message
and otherwise ignore objects that are already removed or freed.  This
would prevent some needless server crashes.

-- 
Jan