Add .luacheckrc and fix its warnings

.luacheckrc

@@ -0,0 +1,22 @@
+std = "lua51c"
+
+ignore = {
+	"21[23]", -- unused argument
+}
+
+max_line_length = 250
+
+read_globals = {
+	"default",
+	"ItemStack",
+	"lucky_block",
+	"minetest",
+	"screwdriver",
+	"vector",
+}
+
+globals = {"hopper"}
+
+files["doc.lua"] = {
+	max_line_length = 9999,
+}

abms.lua

@@ -5,7 +5,7 @@ minetest.register_abm({
 	nodenames = {"hopper:hopper", "hopper:hopper_side"},
 	interval = 1.0,
 	chance = 1,
-	action = function(pos, node, active_object_count, active_object_count_wider)
+	action = function(pos, _, _, active_object_count_wider)
 		if active_object_count_wider == 0 then
 			return
 		end
@@ -85,7 +85,7 @@ minetest.register_abm({
 	chance = 1,
 	catch_up = false,
 
-	action = function(pos, node, active_object_count, active_object_count_wider)
+	action = function(pos, node, _, _)
 		local source_pos, destination_pos, destination_dir
 		if node.name == "hopper:hopper_side" then
 			source_pos = vector.add(pos, directions[node.param2].src)

crafts.lua

@@ -7,14 +7,14 @@ if minetest.get_modpath("default") then
 			{"","default:steel_ingot",""},
 		}
 	})
-	
+
 	minetest.register_craft({
 		output = "hopper:chute",
 		recipe = {
 			{"default:steel_ingot","default:chest","default:steel_ingot"},
 		}
 	})
-	
+
 	minetest.register_craft({
 		output = "hopper:sorter",
 		recipe = {
@@ -23,7 +23,7 @@ if minetest.get_modpath("default") then
 			{"","default:steel_ingot",""},
 		}
 	})
-	
+
 	if not hopper.config.single_craftable_item then
 		minetest.register_craft({
 			output = "hopper:hopper_side",
@@ -32,13 +32,13 @@ if minetest.get_modpath("default") then
 				{"","","default:steel_ingot"},
 			}
 		})
-		
+
 		minetest.register_craft({
 			output = "hopper:hopper_side",
 			type="shapeless",
 			recipe = {"hopper:hopper"},
 		})
-	
+
 		minetest.register_craft({
 			output = "hopper:hopper",
 			type="shapeless",

nodes/chute.lua

@@ -48,10 +48,7 @@ minetest.register_node("hopper:chute", {
 	end,
 
 	on_place = function(itemstack, placer, pointed_thing, node_name)
-		local pos  = pointed_thing.under
 		local pos2 = pointed_thing.above
-		local x = pos.x - pos2.x
-		local z = pos.z - pos2.z
 
 		local returned_stack, success = minetest.item_place_node(itemstack, placer, pointed_thing)
 		if success then

nodes/hoppers.lua

@@ -22,10 +22,10 @@ end
 -- because they are literally *side* hoppers - their spouts point to the side rather than to the front, so
 -- the default item_place_node orientation code will not orient them pointing toward the selected surface.
 local hopper_on_place = function(itemstack, placer, pointed_thing, node_name)
-	local returned_stack, success
+	local returned_stack, success, _
 
 	if not (hopper.config.single_craftable_item or node_name == "hopper:hopper_side") then
-		returned_stack, success = minetest.item_place_node(itemstack, placer, pointed_thing)
+		returned_stack, _ = minetest.item_place_node(itemstack, placer, pointed_thing)
 		return returned_stack
 	end
 
@@ -47,12 +47,12 @@ local hopper_on_place = function(itemstack, placer, pointed_thing, node_name)
 	end
 
 	if param2 then
-		returned_stack, success = minetest.item_place_node(ItemStack("hopper:hopper_side"), placer, pointed_thing, param2)
+		_, success = minetest.item_place_node(ItemStack("hopper:hopper_side"), placer, pointed_thing, param2)
 	else
 		if hopper.config.single_craftable_item then
 			node_name = "hopper:hopper" -- For cases where single_craftable_item was set on an existing world and there are still side hoppers in player inventories
 		end
-		returned_stack, success = minetest.item_place_node(ItemStack(node_name), placer, pointed_thing)
+		_, success = minetest.item_place_node(ItemStack(node_name), placer, pointed_thing)
 	end
 
 	if success then

nodes/sorter.lua

@@ -81,10 +81,7 @@ minetest.register_node("hopper:sorter", {
 	end,
 
 	on_place = function(itemstack, placer, pointed_thing, node_name)
-		local pos  = pointed_thing.under
 		local pos2 = pointed_thing.above
-		local x = pos.x - pos2.x
-		local z = pos.z - pos2.z
 
 		local returned_stack, success = minetest.item_place_node(itemstack, placer, pointed_thing)
 		if success then
@@ -171,44 +168,28 @@ minetest.register_node("hopper:sorter", {
 		local node = minetest.get_node(pos)
 		local dir = minetest.facedir_to_dir(node.param2)
 		local default_destination_pos = vector.add(pos, dir)
-		local default_output_direction
-		if dir.y == 0 then
-			default_output_direction = "horizontal"
-		end
+		local default_output_direction = (dir.y == 0) and "side" or "bottom"
 
 		dir = bottomdir(node.param2)
 		local filter_destination_pos = vector.add(pos, dir)
-		local filter_output_direction
-		if dir.y == 0 then
-			filter_output_direction = "horizontal"
-		end
+		local filter_output_direction = (dir.y == 0) and "side" or "bottom"
 
-		local success = false
+		--- returns success? = true/false
+		local function try_send_item(output_dir, dst_pos)
+			local dst_node = minetest.get_node(dst_pos)
+			local registered_inventories = hopper.get_registered(dst_node.name)
 
-		local filter_destination_node = minetest.get_node(filter_destination_pos)
-		local registered_inventories = hopper.get_registered(filter_destination_node.name)
-		if registered_inventories ~= nil then
-			if filter_output_direction == "horizontal" then
-				success = hopper.send_item_to(pos, filter_destination_pos, filter_destination_node, registered_inventories["side"], filter_items)
-			else
-				success = hopper.send_item_to(pos, filter_destination_pos, filter_destination_node, registered_inventories["bottom"], filter_items)
-			end
-		else
-			success = hopper.send_item_to(pos, filter_destination_pos, filter_destination_node, nil, filter_items)
-		end
-
-		if not success then -- weren't able to put something in the filter destination, for whatever reason. Now we can start moving stuff forward to the default.
-			local default_destination_node = minetest.get_node(default_destination_pos)
-			local registered_inventories = hopper.get_registered(default_destination_node.name)
 			if registered_inventories ~= nil then
-				if default_output_direction == "horizontal" then
-					hopper.send_item_to(pos, default_destination_pos, default_destination_node, registered_inventories["side"])
-				else
-					hopper.send_item_to(pos, default_destination_pos, default_destination_node, registered_inventories["bottom"])
-				end
-			else
-				hopper.send_item_to(pos, default_destination_pos, default_destination_node)
+				return hopper.send_item_to(pos, dst_pos, dst_node, registered_inventories[output_dir], filter_items)
 			end
+
+			return hopper.send_item_to(pos, dst_pos, dst_node, nil, filter_items)
+		end
+
+		if not try_send_item(filter_output_direction, filter_destination_pos) then
+			-- weren't able to put something in the filter destination, for whatever reason.
+			-- Now we can start moving stuff forward to the default.
+			try_send_item(default_output_direction, default_destination_pos)
 		end
 
 		if not inv:is_empty("main") then

utility.lua

@@ -1,4 +1,3 @@
-local S = minetest.get_translator("hopper")
 local FS = hopper.translator_escaped
 -- Target inventory retrieval
 
@@ -76,6 +75,7 @@ local function get_container_inventory(node_pos, inv_info)
 	if get_inventory_fn then
 		inventory = get_inventory_fn(node_pos)
 		if not inventory then
+			local target_node = minetest.get_node(node_pos)
 			minetest.log("error","No inventory from api get_inventory function: " ..
 				target_node.name .. " on " .. vector.to_string(node_pos))
 		end
@@ -131,12 +131,12 @@ end
 
 -- Used to put items from the hopper inventory into the target block
 hopper.send_item_to = function(hopper_pos, target_pos, target_node, target_inv_info, filtered_items)
-	local hopper_meta = minetest.get_meta(hopper_pos)
 	local target_def = minetest.registered_nodes[target_node.name]
 	if not target_def then
 		return false
 	end
 
+	local hopper_meta = minetest.get_meta(hopper_pos)
 	local eject_item = hopper.config.eject_button_enabled and hopper_meta:get_string("eject") == "true" and target_def.buildable_to
 
 	if not eject_item and not target_inv_info then
@@ -144,7 +144,6 @@ hopper.send_item_to = function(hopper_pos, target_pos, target_node, target_inv_i
 	end
 
 	--hopper inventory
-	local hopper_meta = minetest.get_meta(hopper_pos);
 	local hopper_inv = hopper_meta:get_inventory()
 	if hopper_inv:is_empty("main") == true then
 		return false