Fix pipeworks pulling from the wrong chest slot

This removes workarounds related to inv callbacks which were later fixed by the engine.
In addition, pipeworks does (for years) provide the item index, thus such workarounds
were removed too and replaced by using the arguments provided.

Fixes an item duplication when using a pipeworks injector to pull from a digiline chest.

.luacheckrc

@@ -1,13 +1,19 @@
+unused_args = false
+max_line_length = 111
 
 read_globals = {
-	"vector",
-	"screwdriver",
+	"dump",
+
+	"core",
 	"minetest",
+	"vector",
+	"ItemStack",
+	"VoxelArea",
+
 	"default",
 	"pipeworks",
-	"dump",
-	"VoxelArea",
-	"ItemStack",
+	"screwdriver",
+
 }
 
 globals = {

inventory.lua

@@ -1,3 +1,6 @@
+assert(core.features.dynamic_add_media_table,
+	"Digilines requires Luanti/Minetest >= 5.5.0 to work correctly")
+
 local S = digilines.S
 
 local pipeworks_enabled = minetest.get_modpath("pipeworks") ~= nil
@@ -23,7 +26,7 @@ local function send_message(pos, action, stack, from_slot, to_slot, side)
 end
 
 -- Checks if the inventory has become empty and, if so, sends an empty message.
-local function check_empty(pos)
+local function send_empty_if_empty(pos)
 	if minetest.get_meta(pos):get_inventory():is_empty("main") then
 		send_message(pos, "empty")
 	end
@@ -31,7 +34,7 @@ end
 
 -- Checks if the inventory has become full for a particular type of item and,
 -- if so, sends a full message.
-local function check_full(pos, stack)
+local function send_full_if_full(pos, stack)
 	local one_item_stack = ItemStack(stack)
 	one_item_stack:set_count(1)
 	if not minetest.get_meta(pos):get_inventory():room_for_item("main", one_item_stack) then
@@ -42,17 +45,6 @@ end
 local tubeconn = pipeworks_enabled and "^pipeworks_tube_connection_wooden.png" or ""
 local tubescan = pipeworks_enabled and function(pos) pipeworks.scan_for_tube_objects(pos) end or nil
 
--- A place to remember things from allow_metadata_inventory_put to
--- on_metadata_inventory_put. This is a hack due to issue
--- minetest/minetest#6534 that should be removed once that’s fixed.
-local last_inventory_put_index
-local last_inventory_put_stack
-
--- A place to remember things from allow_metadata_inventory_take to
--- tube.remove_items. This is a hack due to issue minetest-mods/pipeworks#205
--- that should be removed once that’s fixed.
-local last_inventory_take_index
-
 local tube_can_insert = function(pos, _, stack, direction)
 	local ret = minetest.get_meta(pos):get_inventory():room_for_item("main", stack)
 	if not ret then
@@ -137,7 +129,7 @@ local tube_insert_object = function(pos, _, original_stack, direction)
 		end
 	end
 	if any_put then
-		check_full(pos, original_stack)
+		send_full_if_full(pos, original_stack)
 	end
 	if stack_count ~= 0 then
 		-- Some items could not be added and bounced back. Report them.
@@ -206,6 +198,7 @@ minetest.register_node("digilines:chest", {
 			action = function() end
 		}
 	},
+	-- pipeworks support
 	tube = {
 		connect_sides = {left=1, right=1, back=1, front=1, bottom=1, top=1},
 		connects = function(i,param2)
@@ -214,47 +207,20 @@ minetest.register_node("digilines:chest", {
 		input_inventory = "main",
 		can_insert = tube_can_insert,
 		insert_object = tube_insert_object,
-		remove_items = function(pos, _, stack, dir, count)
-			-- Here, stack is the ItemStack in our own inventory that is being
-			-- pulled from, NOT the stack that is actually pulled out.
-			-- Combining it with count gives the stack that is pulled out.
-			-- Also, note that Pipeworks doesn’t pass the index to this
-			-- function, so we use the one recorded in
-			-- allow_metadata_inventory_take; because we don’t implement
-			-- tube.can_remove, Pipeworks will call
-			-- allow_metadata_inventory_take instead and will pass it the
-			-- index.
+		remove_items = function(pos, _, stack, dir, count, listname, index)
+			-- This is `on_metadata_inventory_take` but for pipeworks.
 			local taken = stack:take_item(count)
-			minetest.get_meta(pos):get_inventory():set_stack("main", last_inventory_take_index, stack)
-			send_message(pos, "ttake", taken, last_inventory_take_index, nil, dir)
-			check_empty(pos)
+
+			-- However! Pipeworks does not update the stack, thus we must do it.
+			core.get_meta(pos):get_inventory():set_stack(listname, index, stack)
+
+			send_message(pos, "ttake", taken, index, nil, dir)
+			send_empty_if_empty(pos)
 			return taken
 		end,
 	},
-	allow_metadata_inventory_put = function(pos, _, index, stack)
-		-- Remember what was in the target slot before the put; see
-		-- on_metadata_inventory_put for why we care.
-		last_inventory_put_index = index
-		last_inventory_put_stack = minetest.get_meta(pos):get_inventory():get_stack("main", index)
-		return stack:get_count()
-	end,
-	allow_metadata_inventory_take = function(_, _, index, stack)
-		-- Remember the index value; see tube.remove_items for why we care.
-		last_inventory_take_index = index
-		return stack:get_count()
-	end,
 	on_metadata_inventory_move = function(pos, _, from_index, _, to_index, count, player)
-		-- See what would happen if we were to move the items back from in the
-		-- opposite direction. In the event of a normal move, this must
-		-- succeed, because a normal move subtracts some items from the from
-		-- stack and adds them to the to stack; the two stacks naturally must
-		-- be compatible and so the reverse operation must succeed. However, if
-		-- the user *swaps* the two stacks instead, then due to issue
-		-- minetest/minetest#6534, this function is only called once; however,
-		-- when it is called, the stack that used to be in the to stack has
-		-- already been moved to the from stack, so we can detect the situation
-		-- by the fact that the reverse move will fail due to the from stack
-		-- being incompatible with its former contents.
+		-- Detect stack swaps (in the same inventory) by trying to add them together.
 		local inv = minetest.get_meta(pos):get_inventory()
 		local from_stack = inv:get_stack("main", from_index)
 		local to_stack = inv:get_stack("main", to_index)
@@ -283,43 +249,13 @@ minetest.register_node("digilines:chest", {
 		minetest.log("action", player:get_player_name().." moves stuff in chest at "..minetest.pos_to_string(pos))
 	end,
 	on_metadata_inventory_put = function(pos, _, index, stack, player)
-		-- Get what was in the target slot before the put; it has disappeared
-		-- by now (been replaced by the result of the put action) but we saved
-		-- it in allow_metadata_inventory_put. This should always work
-		-- (allow_metadata_inventory_put should AFAICT always be called
-		-- immediately before on_metadata_inventory_put), but in case of
-		-- something weird happening, just fall back to using an empty
-		-- ItemStack rather than crashing.
-		local old_stack
-		if last_inventory_put_index == index then
-			old_stack = last_inventory_put_stack
-			last_inventory_put_index = nil
-			last_inventory_put_stack = nil
-		else
-			old_stack = ItemStack(nil)
-		end
-		-- If the player tries to place a stack into an inventory, there’s
-		-- already a stack there, and the existing stack is either of a
-		-- different item type or full, then obviously the stacks can’t be
-		-- merged; instead the stacks are swapped. This information is not
-		-- reported to mods (Minetest core neither tells us that a particular
-		-- action was a swap, nor tells us a take followed by a put). In core,
-		-- the condition for swapping is that you try to add the new stack to
-		-- the existing stack and the leftovers are as big as the original
-		-- stack to put. Replicate that logic here using the old stack saved in
-		-- allow_metadata_inventory_put. If a swap happened, report it to the
-		-- Digilines network as a utake followed by a uput.
-		local leftovers = old_stack:add_item(stack)
-		if leftovers:get_count() == stack:get_count() then
-			send_message(pos, "utake", old_stack, index)
-		end
 		send_message(pos, "uput", stack, nil, index)
-		check_full(pos, stack)
+		send_full_if_full(pos, stack)
 		minetest.log("action", player:get_player_name().." puts stuff into chest at "..minetest.pos_to_string(pos))
 	end,
 	on_metadata_inventory_take = function(pos, _, index, stack, player)
 		send_message(pos, "utake", stack, index)
-		check_empty(pos)
+		send_empty_if_empty(pos)
 		minetest.log("action", player:get_player_name().." takes stuff from chest at "..minetest.pos_to_string(pos))
 	end
 })
@@ -331,7 +267,7 @@ if minetest.global_exists("tubelib") then
 
 		send_message(passed_speculative_pull.pos, "ttake", passed_speculative_pull.taken,
 				passed_speculative_pull.index, nil, vector.multiply(passed_speculative_pull.dir, -1))
-		check_empty(passed_speculative_pull.pos)
+		send_empty_if_empty(passed_speculative_pull.pos)
 	end
 	local function tube_side(pos, side)
 		if side == "U" then return {x=0,y=-1,z=0}

mod.conf

@@ -5,3 +5,6 @@ description = """
 This mod adds digiline wires, an RTC (Real Time Clock), a light sensor as well as an LCD Screen.
 Can be used together with the luacontroller from mesecons.
 """
+
+# Required due to https://github.com/luanti-org/luanti/issues/6534 (inventory callbacks)
+min_minetest_version = 5.4