Battleground: Fix crash when no players are left in a battleground.

[mostlikely4r]

🍰 Pullrequest

This is a small crashfix which occurs when a battleground ends up empty.

Proof

The code looks pretty clear m_bg is set to nullptr and the next BattleGroundMap::Update does m_bg->
While I'm unsure if there should have been some mechanic to prevent the update after the m_bg is cleared it clearly does not work.
It's very trivial to reproduce and test though.

How2Test

-Join a battleground (".debug bg" to join alone).
-Hearthstone out and the server crashes.

[killerwife]

In what place in code is it set to nullptr if i may ask. Because this might change with the BG rewrite.

[mostlikely4r]

In what place in code is it set to nullptr if i may ask. Because this might change with the BG rewrite.

mangos-wotlk/src/game/Maps/Map.cpp

Line 2133 in 6a6de7b

m_bg = nullptr;

So the first BattleGroundMap::Update sets m_bg to nullptr and the second crashes because it is nullptr.