Fixes HybridDog#16

Added new chat function `in_hell [<player_name>]` and used it to find the bug. The issue was that `local function obsidian_teleport(player, pname, target)` failed to test `nether.trap_players` before modifying `players_in_nether`.

nether/portal.lua

@@ -41,6 +41,7 @@ NETHER['is_player_in_nether'] = function (player)
 		return true
 	end
 end
+local is_player_in_nether = NETHER['is_player_in_nether']
 
 local function save_nether_players()
 	local playernames,n = {},1
@@ -92,11 +93,13 @@ end
 
 -- used for obsidian portal
 local function obsidian_teleport(player, pname, target)
+	if nether.trap_players then
 		minetest.chat_send_player(pname, "For any reason you arrived here. Type " ..
 			"/nether_help to find out things like craft recipes.")
 		players_in_nether[pname] = true
 		save_nether_players()
 		update_background(player, true)
+	end
 	if target then
 		player:set_pos(target)
 	else
@@ -189,6 +192,34 @@ minetest.register_chatcommand("from_hell", {
 	end
 })
 
+-- Useful for debugging Nether player state tracking. Written by Deathwing777
+minetest.register_chatcommand("in_hell", {
+	params = "[<player_name>]",
+	description = "Is the player in hell?",
+	func = function(name, pname)
+		if not minetest.check_player_privs(name, {nether=true}) then
+			return false,
+				"You need the nether priv to execute this chatcommand."
+		end
+		if not player_exists(pname) then
+			pname = name
+		end
+		local player = minetest.get_player_by_name(pname)
+		if not player then
+			return false, "Something went wrong."
+		end
+		
+		status = pname.." is in the "
+		if is_player_in_nether(player) then
+			status = status.."NETHER!"
+		else
+			status = status.."OVERWORLD!"
+		end
+		
+		return true, status
+	end
+})
+
 
 -- Disallow teleportation and change spawn positions if the nether traps players
 if nether.trap_players then