[Freeciv-Dev] (PR#11824) Crashing bug

["Gregory Berkolaiko" <Gregory.Berkolaiko@xxxxxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=11824 >

> [use_less - Thu Jan 13 09:07:38 2005]:
> 
> Well, this bug is a lot more complicated than it looks. :)
> 
> Basically, the function ai_manage_explorer() is going into an infinite
> recursive loop, which eventually crashes the server.  This is caused by
> the fact that the unit exploring tries to get to its exploration
> destination, but its goto fails without using all its moves.  This
> causes the function to try to explore again, but it runs into the same
> situation again, and loops around.

Interesting...
So each time the explorer moves, each time it gets stuck and the
move-points don't decrease?

What sort of situation is it?  I guess there are two railroads both
blocked by enemies?

> I talked about it with Jason on IRC and he suggested this patch, and
> also to ask Greg about it.  Greg?

This patch will cut off too many legitimate cases.
I would go for comparing the move-points instead.  This will also cut
off some legitimate cases (tried to move on a railroad but it's blocked
-- worth a retry, unless the other path will also be blocked) which can
be alleviated by controlling depth of the recursion.

so the condition I would go for is

if (our move points didn't decrease in the last 10 recursive calls) {
  return;
}