Goto Micro AI: prevent potential conflict between Goto MAIs

If several Goto MAIs are used on the same side and both have
unique_goals=yes set, they previously might have interfered with each
other, one preventing the other from working correctly. Now the “goal
taken” information is saved such that it only applies to the CA by
which it was set.

data/ai/micro_ais/cas/ca_goto.lua

@@ -39,13 +39,18 @@ function ca_goto:evaluation(ai, cfg, self)
     local locs = {}
     if cfg.unique_goals then
         -- First, some cleanup of previous turn data
-        local str = 'GO_goals_taken_' .. (wesnoth.current.turn - 1)
-        self.data[str] = nil
+        local str = 'goal_taken_' .. (wesnoth.current.turn - 1)
+        local old_goals = MAISD.get_mai_self_data(self.data, cfg.ai_id)
+        for goal,_ in pairs(old_goals) do
+            if string.find(goal, str) then
+                old_goals[goal] = nil  -- This also removes it from self.data
+            end
+        end
 
         -- Now on to the current turn
-        local str = 'GO_goals_taken_' .. wesnoth.current.turn
         for _,loc in ipairs(all_locs) do
-            if (not self.data[str]) or (not self.data[str]:get(loc[1], loc[2])) then
+            local str = 'goal_taken_' .. wesnoth.current.turn  .. '_' .. loc[1] .. '_' .. loc[2]
+            if (not MAISD.get_mai_self_data(self.data, cfg.ai_id, str)) then
                 table.insert(locs, loc)
             end
         end
@@ -166,9 +171,10 @@ function ca_goto:execution(ai, cfg, self)
 
     -- If 'unique_goals' is set, mark this location as being taken
     if cfg.unique_goals then
-        local str = 'GO_goals_taken_' .. wesnoth.current.turn
-        if (not self.data[str]) then self.data[str] = LS.create() end
-        self.data[str]:insert(closest_hex[1], closest_hex[2])
+        local str = 'goal_taken_' .. wesnoth.current.turn  .. '_' .. closest_hex[1] .. '_' .. closest_hex[2]
+        local tmp_table = {}
+        tmp_table[str] = true
+        MAISD.insert_mai_self_data(self.data, cfg.ai_id, tmp_table)
     end
 
     -- If any of the non-standard path finding options were used,