Only allow builders to guard out of map (#3969)

* Out of map guard only for builder to builder.

luarules/gadgets/unit_prevent_aircraft_hax.lua

@@ -24,17 +24,26 @@ local mapZ = Game.mapSizeZ
 local allMobileUnits = {}
 local spGetUnitPosition = Spring.GetUnitPosition
 local spGetUnitTeam = Spring.GetUnitTeam
+local spGetUnitDefID = Spring.GetUnitDefID
+local spValidUnitID = Spring.ValidUnitID
+local spIsPosInMap = Spring.IsPosInMap
 local CMD_STOP = CMD.STOP
+local CMD_GUARD = CMD.GUARD
 
 local isMobileUnit = {}
+local isBuilder = {}
 for unitDefID, udef in pairs(UnitDefs) do
 	if not (udef.isBuilding or udef.speed == 0) then
 		isMobileUnit[unitDefID] = true
 	end
+	if udef.isBuilder and (udef.buildSpeed and udef.buildSpeed > 0) and (udef.buildDistance and udef.buildDistance > 0) then
+		isBuilder[unitDefID] = true
+	end
 end
 
 function gadget:Initialize()
 	gadgetHandler:RegisterAllowCommand(CMD_STOP)
+	gadgetHandler:RegisterAllowCommand(CMD_GUARD)
 	for _, unitID in pairs(Spring.GetAllUnits()) do
 		gadget:UnitCreated(unitID, Spring.GetUnitDefID(unitID), spGetUnitTeam(unitID))
 	end
@@ -76,12 +85,22 @@ function gadget:GameFrame(f)
 	end
 end
 
+local function isInsideMap(unitID)
+	local x,_,z = spGetUnitPosition(unitID)
+	return spIsPosInMap(x, z)
+end
+
 function gadget:AllowCommand(unitID, unitDefID, teamID, cmdID, cmdParams, cmdOptions, cmdTag, fromSynced, fromLua)
-	-- accepts: CMD_STOP
-	if isMobileUnit[unitDefID] then
-		local x,_,z = Spring.GetUnitPosition(unitID)
-		if z < 0 or x < 0 or z > mapZ or x > mapX then
-			return false
+	if cmdID == CMD_STOP and isMobileUnit[unitDefID] then
+		return isInsideMap(unitID)
+	elseif cmdID == CMD_GUARD then
+		-- To guard out of map both units must be builders
+		local guardeeID = cmdParams[1]
+		if guardeeID and spValidUnitID(guardeeID) and not isInsideMap(guardeeID) then
+			local guardeeUnitDefID = spGetUnitDefID(guardeeID)
+			if not (isBuilder[unitDefID] and isBuilder[guardeeUnitDefID]) then
+				return false
+			end
 		end
 	end
 	return true