Add debug command to spawn mcl_farming plant nodes

This patch adds the debug command “/generate_farming_plant_rows”. The
command generates rows of plants and stems per plant type near a player.
A farming soil or glass node is placed below each node, so players can
find and examine possible gaps between a plant node and a node below.

mods/ITEMS/mcl_farming/init.lua

@@ -27,3 +27,73 @@ dofile(minetest.get_modpath("mcl_farming").."/potatoes.lua")
 
 -- ========= BEETROOT =========
 dofile(minetest.get_modpath("mcl_farming").."/beetroot.lua")
+
+-- This function generates a row of plantlike and nodebox nodes whose
+-- name starts with a given string, starting at a given position. It
+-- places a given node below so that the rendering can be examined.
+local function generate_plant_row(prefix, pos, below_node)
+	local i = 1
+	for node_name, node in pairs(minetest.registered_nodes) do
+		if (
+			1 == node_name:find(prefix) and
+			(
+				"plantlike" == node.drawtype or
+				"nodebox" == node.drawtype
+			)
+		) then
+			local node_pos = {
+				x = pos.x + i,
+				y = pos.y,
+				z = pos.z,
+			}
+			minetest.set_node(
+				node_pos,
+				{
+					name = node_name,
+					param2 = node.place_param2 or 0
+				}
+			)
+			local below_pos = {
+				x = node_pos.x,
+				y = node_pos.y - 1,
+				z = node_pos.z
+			}
+			minetest.set_node(
+				below_pos,
+				below_node
+			)
+			i = i + 1
+		end
+	end
+end
+
+minetest.register_chatcommand("generate_farming_plant_rows",{
+	description = "Generates rows of mcl_farming plant nodes on farming soil and glass",
+	privs = { debug = true },
+	func = function(name, param)
+		local player = minetest.get_player_by_name(name)
+		local pos = player:get_pos()
+		local node_prefixes = {
+			"mcl_farming:beetroot",
+			"mcl_farming:carrot",
+			"mcl_farming:melon",
+			"mcl_farming:potato",
+			"mcl_farming:pumpkin",
+			"mcl_farming:wheat",
+		}
+		for i,node_prefix in ipairs(node_prefixes) do
+			generate_plant_row(
+				node_prefix,
+				pos,
+				{ name = "mcl_farming:soil" }
+			)
+			pos.z = pos.z + 2
+			generate_plant_row(
+				node_prefix,
+				pos,
+				{ name = "mcl_core:glass" }
+			)
+			pos.z = pos.z + 2
+		end
+	end
+})