Deallocated Memory on teardown of Military site

[Klaus Halfmann]

I wanted to teardown some militray bulding, and closed the building window before
Game:think() was called. So the BuildingWindow has already died() but still
got some notification.

Call stack looks like:
Player::dismantle_building(Building* building)
...
BuildingWindow::on_building_note)
-> building_.serial() -> Use of deallocated Memory

* A quick fix would be:
  void BuildingWindow::on_building_note(const Widelands::NoteBuilding& note) {
     if (!is_dying && note.serial == building_.serial()) {
 switch (note.action) {

* Should this not be done via some "unregestration"? this would mean
  that we would leak some Memory for every such subscription?

Thanks to http://clang.llvm.org/docs/AddressSanitizer.html

[Klaus Halfmann (klaus-halfmann)]

Same problem in ProductionSiteWindow, check for !is_dying_ is already there but was
done _after_ the broken access.

[GunChleoc (gunchleoc)]

I had been struggling with those when I implemented them - a fix will be very much appreciated :)

[SirVer (sirver)]

I looked at this and agree with klaus fix. I proposed a branch to get this fixed. Thanks, Klaus!

> * Should this not be done via some "unregestration"? this would mean that we would leak some Memory for every such subscription?

it is unregistered as soon as the subscriber is deleted once the window object is deleted. die() registers a window to be closed on the next logical frame, so it is perfectly valid that it still receives NoteBuilding for the moment. Of course, the underlying building is deleted, so we cannot access it anymore. We use is_dying_ as a proxy of 'i do no longer care and the building might be gone anyways' now.

[GunChleoc (gunchleoc)]

Fixed in build20-rc1