TrinityCore/TrinityCore — comment on commit 394dbf0cdceea425a1ad63ecebc614e29728d365
File: src/server/game/Calendar/CalendarMgr.cpp line 398
By Spp-:

Wild pointer? did you saw the next lines?
if (something)
calendarEvent = whatever1;
else
calendarEvent = whatever2;

So that Null is not needed at all.