Fix crash when selecting shared spawn for a player that just left. Now GUI is updated immediately. closes #174

lib/separate_spawns.lua

@@ -760,6 +760,11 @@ function RemoveOrResetPlayer(player, remove_player)
     if (remove_player) then
         game.remove_offline_players({ player })
     end
+
+    -- Refresh the shared spawn spawn gui for all players
+    for _,p in pairs(game.connected_players) do
+        RefreshSharedSpawnFrameIfExist(p)
+    end
 end
 
 ---Searches all unique spawns for the primary one for a player. This will return null if they joined someeone else's spawn.
@@ -771,6 +776,7 @@ function FindPrimaryUniqueSpawn(player_name)
             return spawns[player_name]
         end
     end
+    return nil
 end
 
 ---Find the primary home spawn of a player, if one exists. It could be they joined a shared spawn.

lib/separate_spawns_guis.lua

@@ -842,7 +842,9 @@ function SharedSpawnSelect(gui_element, player)
         local button = gui_element.parent.join_other_spawn
 
         local primary_spawn = FindPrimaryUniqueSpawn(host_name)
-        if (IsSharedSpawnOpen(primary_spawn.surface_name, host_name) and not IsSharedSpawnFull(primary_spawn.surface_name, host_name)) then
+        if (primary_spawn and 
+                IsSharedSpawnOpen(primary_spawn.surface_name, host_name) and
+                not IsSharedSpawnFull(primary_spawn.surface_name, host_name)) then
             global.spawn_choices[player.name].host = host_name
             button.enabled = true
             button.caption = { "oarc-join-shared-button-enable", host_name, primary_spawn.surface_name }