make sure a listed block is indeed loaded before writing to it

(in case the mapgen takes long enough on a server that players
have wandered off and the server has unloaded blocks)

init.lua

@@ -34,7 +34,7 @@ local function tableize(s)
 	return string.split(string.trim(string.gsub(s, " ", "")))
 end
 
-local c1 = minetest.settings:get("biome_lib_default_grow_through_nodes")
+local c1 minetest.settings:get("biome_lib_default_grow_through_nodes")
 biome_lib.default_grow_through_nodes = {["air"] = true}
 if c1 then
 	for _, i in ipairs(tableize(c1)) do
@@ -44,7 +44,7 @@ else
 	biome_lib.default_grow_through_nodes["default:snow"] = true
 end
 
-local c2 = minetest.settings:get("biome_lib_default_water_nodes")
+local c2 minetest.settings:get("biome_lib_default_water_nodes")
 biome_lib.default_water_nodes = {}
 if c2 then
 	for _, i in ipairs(tableize(c2)) do
@@ -427,22 +427,10 @@ function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes,
 	return items_added
 end
 
--- make sure the target block and all 6 neighbors are actually loaded.
-
-local function confirm_block_surroundings(pos)
-	return minetest.get_node_or_nil(pos)
-	  and minetest.get_node_or_nil({ x=pos.x-16, y=pos.y,   z=pos.z   })
-	  and minetest.get_node_or_nil({ x=pos.x+16, y=pos.y,   z=pos.z   })
-	  and minetest.get_node_or_nil({ x=pos.x,   y=pos.y-16, z=pos.z   })
-	  and minetest.get_node_or_nil({ x=pos.x,   y=pos.y+16, z=pos.z   })
-	  and minetest.get_node_or_nil({ x=pos.x,   y=pos.y,   z=pos.z-16 })
-	  and minetest.get_node_or_nil({ x=pos.x,   y=pos.y,   z=pos.z+16 })
-end
-
 -- Primary mapgen spawner, for mods that can work with air checking enabled on
 -- a surface during the initial map read stage.
 
-function biome_lib:generate_block_with_air_checking(shutdown)
+function biome_lib:generate_block_with_air_checking()
 	if not biome_lib.blocklist_aircheck[1] then
 		return
 	end
@@ -462,10 +450,8 @@ function biome_lib:generate_block_with_air_checking(shutdown)
 		if #biome_lib.surface_nodes_aircheck.blockhash > 0 then
 			biome_lib:dbg("Mapblock at "..minetest.pos_to_string(minp).." added, with "..#biome_lib.surface_nodes_aircheck.blockhash.." surface nodes detected.")
 		end
-	elseif not shutdown and not confirm_block_surroundings(minp) and #biome_lib.blocklist_aircheck > 1 then
-		biome_lib.blocklist_aircheck[#biome_lib.blocklist_aircheck+1] = biome_lib.blocklist_aircheck[1]
-		table.remove(biome_lib.blocklist_aircheck, 1)
-		biome_lib:dbg("Mapblock at "..minetest.pos_to_string(minp).." had an unloaded neighbor, moved it to the end of the queue.")
+	elseif not minetest.get_node_or_nil(minp) then
+		minetest.load_area(minp)
 	else
 		if biome_lib.actionslist_aircheck[biome_lib.actioncount_aircheck.blockhash] then
 			-- [1] is biome, [2] is node/function/model
@@ -489,7 +475,7 @@ end
 -- Secondary mapgen spawner, for mods that require disabling of
 -- checking for air during the initial map read stage.
 
-function biome_lib:generate_block_no_aircheck(shutdown)
+function biome_lib:generate_block_no_aircheck()
 	if not biome_lib.blocklist_no_aircheck[1] then
 		return
 	end
@@ -503,9 +489,8 @@ function biome_lib:generate_block_no_aircheck(shutdown)
 		biome_lib.surface_nodes_no_aircheck.blockhash =
 			minetest.find_nodes_in_area(minp, maxp, biome_lib.surfaceslist_no_aircheck)
 		biome_lib.actioncount_no_aircheck.blockhash = 1
-	elseif not shutdown and not confirm_block_surroundings(minp) and #biome_lib.blocklist_no_aircheck > 1 then
-		biome_lib.blocklist_no_aircheck[#biome_lib.blocklist_no_aircheck+1] = biome_lib.blocklist_no_aircheck[1]
-		table.remove(biome_lib.blocklist_no_aircheck, 1)
+	elseif not minetest.get_node_or_nil(minp) then
+		minetest.load_area(minp)
 	else
 		if biome_lib.actionslist_no_aircheck[biome_lib.actioncount_no_aircheck.blockhash] then
 			biome_lib:populate_surfaces(
@@ -536,10 +521,10 @@ minetest.register_globalstep(function(dtime)
 	while (#biome_lib.blocklist_aircheck > 0 or #biome_lib.blocklist_no_aircheck > 0)
 	  and biome_lib.globalstep_runtime < 200000 do  -- 0.2 seconds, in uS.
 		if #biome_lib.blocklist_aircheck > 0 then
-			biome_lib:generate_block_with_air_checking(false)
+			biome_lib:generate_block_with_air_checking()
 		end
 		if #biome_lib.blocklist_no_aircheck > 0 then
-			biome_lib:generate_block_no_aircheck(false)
+			biome_lib:generate_block_no_aircheck()
 		end
 		biome_lib.globalstep_runtime = minetest.get_us_time() - biome_lib.globalstep_start_time
 	end
@@ -556,7 +541,7 @@ minetest.register_on_shutdown(function()
 	print("[biome_lib] Stand by, playing out the rest of the aircheck mapblock log")
 	print("(there are "..#biome_lib.blocklist_aircheck.." entries)...")
 	while #biome_lib.blocklist_aircheck > 0 do
-		biome_lib:generate_block_with_air_checking(true)
+		biome_lib:generate_block_with_air_checking(0.1)
 	end
 end)
 
@@ -568,7 +553,7 @@ minetest.register_on_shutdown(function()
 	print("[biome_lib] Stand by, playing out the rest of the no-aircheck mapblock log")
 	print("(there are "..#biome_lib.blocklist_no_aircheck.." entries)...")
 	while #biome_lib.blocklist_no_aircheck > 0 do
-		biome_lib:generate_block_no_aircheck(true)
+		biome_lib:generate_block_no_aircheck(0.1)
 	end
 end)