Bottleneck MAI: bug fix for when allied units are present

Hexes occupied by allied units were previously not excluded properly by
the AI, which could lead to error messages and the candidate action to
be blacklisted.

data/ai/micro_ais/cas/ca_bottleneck_move.lua

@@ -327,6 +327,18 @@ function ca_bottleneck_move:evaluation(ai, cfg, self)
         end
     end
 
+    -- Get a map of the allies, as hexes occupied by allied units count as
+    -- reachable, but must be excluded. This could also be done below by
+    -- using bottleneck_move_out_of_way(), but this is much faster
+    local allies = AH.get_live_units {
+        { "filter_side", { { "allied_with", { side = wesnoth.current.side } } } },
+        { "not", { side = wesnoth.current.side } }
+    }
+    local allies_map = LS.create()
+    for _,ally in ipairs(allies) do
+        allies_map:insert(ally.x, ally.y)
+    end
+
     local max_rating, best_unit, best_hex = 0
     for _,unit in ipairs(units) do
         local is_healer = (unit.__cfg.usage == "healer")
@@ -351,6 +363,9 @@ function ca_bottleneck_move:evaluation(ai, cfg, self)
             -- If the target hex is occupied, give it a small penalty
             if current_rating_map:get(loc[1], loc[2]) then rating = rating - 0.001 end
 
+            -- Also need to exclude hexes occupied by an allied unit
+            if allies_map:get(loc[1], loc[2]) then rating = 0 end
+
             -- Now only valid and possible moves should have a rating > 0
             if (rating > max_rating) then
                 max_rating, best_unit, best_hex = rating, unit, { loc[1], loc[2] }