Allow disabling the seeder unit of cultivators with a seeder configuration (#989)

scripts/ai/controllers/SowingMachineController.lua

@@ -10,19 +10,19 @@ end
 
 function SowingMachineController:update()
 	if not self.settings.optionalSowingMachineEnabled:getIsDisabled() then
-		if self.settings.optionalSowingMachineEnabled:getValue() then 
+		if self.settings.optionalSowingMachineEnabled:getValue() then
 			--- Makes sure the sowing machine get's turned on
 			if not self.implement:getIsTurnedOn() then
 				self.implement:setIsTurnedOn(true)
 			end
-		else 
+		else
 			--- Makes sure the sowing machine is turned off if not needed.
 			if self.implement:getIsTurnedOn() then
 				self.implement:setIsTurnedOn(false)
 			end
 		end
 	end
-	if self.sowingMachineSpec.showWrongFruitForMissionWarning then 
+	if self.sowingMachineSpec.showWrongFruitForMissionWarning then
 		self:debug("Wrong fruit type for mission selected!")
 		self.vehicle:stopCurrentAIJob(AIMessageErrorWrongMissionFruitType.new())
 	end
@@ -41,15 +41,50 @@ function SowingMachineController:onFinished()
     self.implement:setIsTurnedOn(false)
 end
 
+--- While Courseplay is driving and sowing was disabled by the user, the machine stays turned off.
+--- Without this override, TurnOnVehicle:getCanAIImplementContinueWork() fails for machines that
+--- require turning on but are turned off, so the driver would lower the implement and then just
+--- stand still, waiting forever (#989).
+local function getAIRequiresTurnOn(implement, superFunc, ...)
+	--- Only for cultivators with a seeder unit configuration, like the Horsch Finer 6 SL.
+	--- The structural check must not go through the setting's getIsDisabled() here, as that
+	--- calls isOptionalSowingMachineSettingVisible(), which in turn calls getAIRequiresTurnOn(),
+	--- resulting in an infinite recursion.
+	if implement.spec_sowingMachine ~= nil and
+			SpecializationUtil.hasSpecialization(Cultivator, implement.specializations) then
+		local rootVehicle = implement.rootVehicle
+		if rootVehicle ~= nil and rootVehicle.getIsCpActive and rootVehicle:getIsCpActive() then
+			local setting = rootVehicle:getCpSettings().optionalSowingMachineEnabled
+			if not setting:getValue() then
+				return false
+			end
+		end
+	end
+	return superFunc(implement, ...)
+end
+TurnOnVehicle.getAIRequiresTurnOn = Utils.overwrittenFunction(
+	TurnOnVehicle.getAIRequiresTurnOn, getAIRequiresTurnOn)
+
 -------------------------
 --- Refill handling
 -------------------------
 
 function SowingMachineController:needsRefilling()
+	if not self.settings.optionalSowingMachineEnabled:getIsDisabled() and
+			not self.settings.optionalSowingMachineEnabled:getValue() then
+		--- Sowing was disabled by the user, so no seeds are needed (#989).
+		return false
+	end
+	if self.implement:getFillUnitCapacity(self.sowingMachineSpec.fillUnitIndex) == 0 then
+		--- Sowing machines without a real seed tank (capacity 0), like the seeder unit
+		--- of the Horsch Finer 6 SL, don't consume seeds (see getSowingMachineCanConsume)
+		--- and therefore never need refilling (#989).
+		return false
+	end
 	if not g_currentMission.missionInfo.helperBuySeeds then
-		if self.implement:getFillUnitFillLevel(self.sowingMachineSpec.fillUnitIndex) <= 0 then 
+		if self.implement:getFillUnitFillLevel(self.sowingMachineSpec.fillUnitIndex) <= 0 then
 			return ImplementController.needsRefilling(self)
 		end
 	end
 	return false
-end
+end

scripts/specializations/CpVehicleSettings.lua

@@ -358,12 +358,21 @@ end
 
 function CpVehicleSettings:isOptionalSowingMachineSettingVisible()
     local vehicles, found = AIUtil.getAllChildVehiclesWithSpecialization(self, SowingMachine)
-    return found and not vehicles[1]:getAIRequiresTurnOn()
+    if not found then
+        return false
+    end
+    if not vehicles[1]:getAIRequiresTurnOn() then
+        --- Passive sowing machines, for example a roller with a seeder configuration.
+        return true
+    end
+    --- Cultivators with a seeder unit configuration, like the Horsch Finer 6 SL,
+    --- are primarily cultivators, so sowing is optional for them as well, even
+    --- though their seeder unit needs to be turned on (#989).
+    return SpecializationUtil.hasSpecialization(Cultivator, vehicles[1].specializations)
 end
 
 function CpVehicleSettings:isOptionalSowingMachineSettingDisabled()
-    local vehicles, found = AIUtil.getAllChildVehiclesWithSpecialization(self, SowingMachine)
-    return not found or vehicles[1]:getAIRequiresTurnOn()
+    return not CpVehicleSettings.isOptionalSowingMachineSettingVisible(self)
 end