Fix minetest.item_eat's replace_with_item, fixes #2292

builtin/game/item.lua

@@ -357,8 +357,7 @@ function core.item_drop(itemstack, dropper, pos)
 	return itemstack
 end
 
-function core.item_eat(hp_change, replace_with_item)
-	return function(itemstack, user, pointed_thing)  -- closure
+function core.do_item_eat(hp_change, replace_with_item, itemstack, user, pointed_thing)
 	for _, callback in pairs(core.registered_on_item_eats) do
 		local result = callback(hp_change, replace_with_item, itemstack, user, pointed_thing)
 		if result then
@@ -367,10 +366,29 @@ function core.item_eat(hp_change, replace_with_item)
 	end
 	if itemstack:take_item() ~= nil then
 		user:set_hp(user:get_hp() + hp_change)
-			itemstack:add_item(replace_with_item) -- note: replace_with_item is optional
+
+		if replace_with_item then
+			if itemstack:is_empty() then
+				itemstack:add_item(replace_with_item)
+			else
+				local inv = user:get_inventory()
+				if inv:room_for_item("main", {name=replace_with_item}) then
+					inv:add_item("main", replace_with_item)
+				else
+					local pos = user:getpos()
+					pos.y = math.floor(pos.y + 0.5)
+					core.add_item(pos, replace_with_item)
+				end
+			end
+		end
 	end
 	return itemstack
 end
+
+function core.item_eat(hp_change, replace_with_item)
+	return function(itemstack, user, pointed_thing)  -- closure
+		return core.do_item_eat(hp_change, replace_with_item, itemstack, user, pointed_thing)
+	end
 end
 
 function core.node_punch(pos, node, puncher, pointed_thing)

doc/lua_api.txt

@@ -1926,6 +1926,8 @@ and `minetest.auth_reload` call the authetification handler.
 * `minetest.create_detached_inventory(name, callbacks)`: returns an `InvRef`
     * callbacks: See "Detached inventory callbacks"
     * Creates a detached inventory. If it already exists, it is cleared.
+* `minetest.do_item_eat(hp_change, replace_with_item, itemstack, user, pointed_thing)`: returns left over ItemStack
+    * See `minetest.item_eat` and `minetest.register_on_item_eat`
 
 ### Formspec
 * `minetest.show_formspec(playername, formname, formspec)`
@@ -2037,7 +2039,11 @@ These functions return the leftover itemstack.
 * `minetest.item_drop(itemstack, dropper, pos)`
     * Drop the item
 * `minetest.item_eat(hp_change, replace_with_item)`
-    * Eat the item. `replace_with_item` can be `nil`.
+    * Eat the item.
+    * `replace_with_item` is the itemstring which is added to the inventory.
+      If the player is eating a stack, then replace_with_item goes to a
+      different spot. Can be `nil`
+    * See `minetest.do_item_eat`
 
 ### Defaults for the `on_punch` and `on_dig` node definition callbacks
 * `minetest.node_punch(pos, node, puncher, pointed_thing)`