Add debug command to acquire a written book

The “getwrittenbook” command gives a player that has the “debug” privilege a book
with a configurable amount of characters. This was added as a debug aid, to help
reproducing situations in which items with lots of metadata trigger issues like
heavy lag or server crashes.

mods/ENTITIES/mcl_item_entity/init.lua

@@ -1,3 +1,4 @@
+local S = minetest.get_translator("mcl_item_entity")
 --basic settings
 local item_drop_settings                 = {} --settings table
 item_drop_settings.age                   = 1.0 --how old a dropped item (_insta_collect==false) has to be before collecting
@@ -781,3 +782,29 @@ minetest.register_entity(":__builtin:item", {
 
 	-- Note: on_punch intentionally left out. The player should *not* be able to collect items by punching
 })
+
+-- The “getwrittenbook” command was added as a debug aid. It can help
+-- reproducing situations in which items with lots of metadata trigger
+-- issues like heavy lag or server crashes. Do not remove this command
+-- unless another easy way of getting items with overlong meta exists!
+--
+-- “/getwrittenbook 65323” creates an item that creates the largest
+-- possible serializable written book item entity when dropped.
+--
+-- “/getwrittenbook 65324” creates an item that creates the smallest
+-- possible non-serializable written book item entity when dropped.
+minetest.register_chatcommand("getwrittenbook", {
+	params = S("<Count>"),
+	description = S("Get a written book with a configurable amount of characters."),
+	privs = {debug=true},
+	func = function(name, param)
+		local count = tonumber(param)
+		local itemstack = ItemStack("mcl_books:written_book")
+		local meta = itemstack:get_meta()
+		meta:set_string("description", "")
+		meta:set_string("text", string.rep("x", count))
+		local player = minetest.get_player_by_name(name)
+		local inv = player:get_inventory()
+		inv:add_item("main", itemstack)
+	end
+})