missing checks to rare cases of nill players for slow connections

i my server got this in some mods that have heavy usage of loop on connected players ERROR[Main]: ServerError: AsyncErr: ServerThread::run Lua: Runtime error from mod 'ambience' in callback LuaABM::trigger()

that happened cos there's some loops around the connected players.. but in VERY HUGE amount of .. there's no so enought fast secuence to check if player still are valid..

so i made this:

index b378257..ca861c2 100644
--- a/init.lua
+++ b/init.lua
@@ -91,12 +91,16 @@ end
 
 -- setup table when player joins
 minetest.register_on_joinplayer(function(player)
-       playing[player:get_player_name()] = {music = -1}
+       if player ~= nil then
+               playing[player:get_player_name()] = {music = -1}
+       end
 end)
 
 -- remove table when player leaves
 minetest.register_on_leaveplayer(function(player)
-       playing[player:get_player_name()] = nil
+       if player ~= nil then
+               playing[player:get_player_name()] = nil
+       end
 end)
 
 
@@ -199,7 +203,9 @@ minetest.register_globalstep(function(dtime)
        -- loop through players
        for _, player in ipairs(minetest.get_connected_players()) do
 
-               player_name = player:get_player_name()
+               if player == nil then
+                       return
+               end
 
 --local t1 = os.clock()

i must made a pull request or you will respond in fast enought time? i'll wait for 1 day.

#13 missing checks to rare cases of nill players for slow connections