Fix problems with incorrectly destructed teleport tubes.

teleport_tube.lua

@@ -3,10 +3,10 @@ local filename=minetest.get_worldpath() .. "/teleport_tubes"
 
 local function read_file()
 	local f = io.open(filename, "r")
-	if f==nil then return {} end
+	if f == nil then return {} end
     	local t = f:read("*all")
     	f:close()
-	if t=="" or t==nil then return {} end
+	if t == "" or t == nil then return {} end
 	return minetest.deserialize(t)
 end
 
@@ -18,8 +18,8 @@ end
 
 local function update_pos_in_file(pos)
 	local tbl=read_file()
-	for _,val in ipairs(tbl) do
-		if val.x==pos.x and val.y==pos.y and val.z==pos.z then
+	for _, val in ipairs(tbl) do
+		if val.x == pos.x and val.y == pos.y and val.z == pos.z then
 			local meta = minetest.get_meta(val)
 			val.channel = meta:get_string("channel")
 			val.cr = meta:get_int("can_receive")
@@ -40,34 +40,56 @@ local function add_tube_in_file(pos,channel, cr)
 end
 
 local function remove_tube_in_file(pos)
-	local tbl=read_file()
-	local newtbl={}
-	for _,val in ipairs(tbl) do
-		if val.x~=pos.x or val.y~=pos.y or val.z~=pos.z then
-			table.insert(newtbl,val)
+	local tbl = read_file()
+	local newtbl = {}
+	for _, val in ipairs(tbl) do
+		if val.x ~= pos.x or val.y ~= pos.y or val.z ~= pos.z then
+			table.insert(newtbl, val)
 		end
 	end
 	write_file(newtbl)
 end
 
+local function read_node_with_vm(pos)
+	local vm = VoxelManip()
+	local MinEdge, MaxEdge = vm:read_from_map(pos, pos)
+	local data = vm:get_data()
+	local area = VoxelArea:new({MinEdge = MinEdge, MaxEdge = MaxEdge})
+	return minetest.get_name_from_content_id(data[area:index(pos.x, pos.y, pos.z)])
+end
+
 local function get_tubes_in_file(pos,channel)
-	local tbl=read_file()
-	local newtbl={}
-	local changed=false
-	for _,val in ipairs(tbl) do
-		local node = minetest.get_node(val)
+	local tbl = read_file()
+	local newtbl = {}
+	local changed = false
+	for _, val in ipairs(tbl) do
 		local meta = minetest.get_meta(val)
-		-- That shouldn't be needed anymore since the mvps callback, but we leave it nevertheless
-		if node.name~="ignore"  and (val.channel~=meta:get_string("channel") or val.cr~=meta:get_int("can_receive")) then
-			val.channel=meta:get_string("channel")
-			val.cr=meta:get_int("can_receive")
-			changed=true
-		end
-		if val.cr==1 and val.channel==channel and (val.x~=pos.x or val.y~=pos.y or val.z~=pos.z) then
-			table.insert(newtbl,val)
+		local name = read_node_with_vm(val)
+		local is_loaded = (minetest.get_node_or_nil(val) ~= nil)
+		local is_teleport_tube = minetest.registered_nodes[name] and minetest.registered_nodes[name].is_teleport_tube
+		if is_teleport_tube then
+			if is_loaded and (val.channel ~= meta:get_string("channel") or val.cr ~= meta:get_int("can_receive")) then
+				val.channel = meta:get_string("channel")
+				val.cr = meta:get_int("can_receive")
+				changed = true
+			end
+			if val.cr == 1 and val.channel == channel and (val.x ~= pos.x or val.y ~= pos.y or val.z ~= pos.z) then
+				table.insert(newtbl, val)
+			end
+		else
+			val.to_remove = true
+			changed = true
 		end
 	end
-	if changed then write_file(tbl) end
+	if changed then
+		local updated = {}
+		for _, val in ipairs(tbl) do
+			if not val.to_remove then
+				table.insert(updated, val)
+			end
+		end
+		write_file(updated)
+	end
 	return newtbl
 end
 
@@ -82,6 +104,7 @@ local teleport_inv_texture="pipeworks_teleport_tube_inv.png"
 
 pipeworks.register_tube("pipeworks:teleport_tube","Teleporter pneumatic tube segment",teleport_plain_textures,
 	teleport_noctr_textures,teleport_end_textures,teleport_short_texture,teleport_inv_texture, {
+	is_teleport_tube = true,
 	tube = {
 		can_go = function(pos,node,velocity,stack)
 			velocity.x = 0