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

@@ -9,8 +9,6 @@
 biome_lib = {}
 biome_lib.air = {name = "air"}
 
-plantslib = setmetatable({}, { __index=function(t,k) print("Use of deprecated function:", k) return biome_lib[k] end })
-
 biome_lib.blocklist_aircheck = {}
 biome_lib.blocklist_no_aircheck = {}
 
@@ -160,7 +158,7 @@ function biome_lib:set_defaults(biome)
 	biome.near_nodes_size = biome.near_nodes_size or 0
 	biome.near_nodes_count = biome.near_nodes_count or 1
 	biome.rarity = biome.rarity or 50
-	biome.max_count = biome.max_count or 5
+	biome.max_count = biome.max_count or 125
 	if biome.check_air ~= false then biome.check_air = true end
 
 -- specific to abm spawner
@@ -331,6 +329,7 @@ local function populate_single_surface(biome, pos, perlin_fertile_area, checkair
 end
 
 function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes, checkair)
+	local items_added = 0
 
 	biome_lib:set_defaults(biome)
 
@@ -351,10 +350,10 @@ function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes,
 	local num_in_biome_nodes = #in_biome_nodes
 
 	if num_in_biome_nodes == 0 then
-		return
+		return 0
 	end
 
-	for i = 1, math.min(biome.max_count, num_in_biome_nodes) do
+	for i = 1, math.min(math.ceil(biome.max_count/25), num_in_biome_nodes) do
 		local tries = 0
 		local spawned = false
 		while tries < 2 and not spawned do
@@ -423,7 +422,9 @@ function biome_lib:populate_surfaces(biome, nodes_or_function_or_model, snodes,
 				tries = tries + 1
 			end
 		end
+		if spawned then items_added = items_added + 1 end
 	end
+	return items_added
 end
 
 -- Primary mapgen spawner, for mods that can work with air checking enabled on
@@ -446,14 +447,22 @@ function biome_lib:generate_block_with_air_checking()
 		biome_lib.surface_nodes_aircheck.blockhash =
 			minetest.find_nodes_in_area_under_air(minp, maxp, biome_lib.surfaceslist_aircheck)
 		biome_lib.actioncount_aircheck.blockhash = 1
-
+		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 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
-			biome_lib:populate_surfaces(
+			local added = biome_lib:populate_surfaces(
 				biome_lib.actionslist_aircheck[biome_lib.actioncount_aircheck.blockhash][1],
 				biome_lib.actionslist_aircheck[biome_lib.actioncount_aircheck.blockhash][2],
 				biome_lib.surface_nodes_aircheck.blockhash, true)
+			if added > 0 then
+				biome_lib:dbg("Ran biome_lib:populate_surfaces for block at "..minetest.pos_to_string(minp)..
+					".  Entry #"..biome_lib.actioncount_aircheck.blockhash.." added "..added.." items.")
+			end
 			biome_lib.actioncount_aircheck.blockhash = biome_lib.actioncount_aircheck.blockhash + 1
 		else
 			table.remove(biome_lib.blocklist_aircheck, 1)
@@ -480,7 +489,8 @@ function biome_lib:generate_block_no_aircheck()
 		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 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(