Get rid of recursive call in default.dig_up (#3133)

game_api.txt

@@ -1217,3 +1217,11 @@ These can be influenced using this API.
 * `player`: ObjectRef of the relevant player
 * You can override this function to change the weather effects by simply returning different values.
   Setting `clouds` or `lighting` in the result table to `nil` will *prevent* those from changing.
+
+Utilities
+---------
+
+`default.dig_up(pos, node, digger, max_height)`
+
+ * Find all nodes above `pos` that is the same, then dig them all
+ * `max_height`	Maximum number of nodes to iterate. Default: 100

mods/default/functions.lua

@@ -293,15 +293,32 @@ minetest.register_abm({
 -- Dig upwards
 --
 
-function default.dig_up(pos, node, digger)
+local in_dig_up = false
+
+function default.dig_up(pos, node, digger, max_height)
+	if in_dig_up then return end -- Do not recurse
 	if digger == nil then return end
-	local np = {x = pos.x, y = pos.y + 1, z = pos.z}
+	max_height = max_height or 100
-	local nn = minetest.get_node(np)
+
-	if nn.name == node.name then
+	in_dig_up = true
-		minetest.node_dig(np, nn, digger)
+	for y = 1, max_height do
+		local up_pos  = vector.offset(pos, 0, y, 0)
+		local up_node = minetest.get_node(up_pos)
+		if up_node.name ~= node.name then
+			break
 		end
+		if not minetest.node_dig(up_pos, up_node, digger) then
+			break
+		end
+	end
+	in_dig_up = false
 end
 
+-- errors are hard to handle, instead we rely on resetting this value the next step
+minetest.register_globalstep(function()
+	in_dig_up = false
+end)
+
 
 --
 -- Fence registration helper