[Freeciv-Dev] (PR#2631) [Bug] ACTIVITY_EXPLORE infinite cycle

["Gregory Berkolaiko via RT" <rt@xxxxxxxxxxxxxx>]

This is a bug connected to the recent addition of ai_unit_goto wrapping 
to CVS.

The cycle goes like this:

1. ai_manage_explorer asks ai_unit_goto to move the unit
2. ai_unit_goto cannot do it ("Ending turn early to stay out of trouble")
 and attempts to reset the activity to ACTIVITY_EXPLORE 
3. handle_unit_activity_request calls handle_unit_activity_dependencies
 which calls ai_manage_explorer
Since the unit hasn't moved the situation comes back to 1.

I attach a savegame (probably will be stripped).  To recreate the bug, 
join as Stefan Uros (AI managed), press Turn Done 4 times and you are in a 
loop.  Press Ctrl-C in your server window to break.

I have two possible fixes for this problem but both are kludges.  I will 
send them in a minute (need a PR# first).

G.

act_cycle.sav.gz
Description: act_cycle.sav.gz