ZDoom

Fixed.

The problem here was that the entire logic for thinker destruction was just facepalm inducing.
It's not the first time I had to redo such careless code of 'self-deleting' linked lists and I think there's a few more lurking in the shadows.

The main loop depended on the side effect that destroying a thinker would unlink it. Just too bad that this won't happen if an exception occurs - especially one that isn't handled properly.
I changed it so that the linked list is taken down entirely before even starting the deletion. This way I can be sure that even if some unknown exception passes through here it won't result in a stale list.

Fatal errors behave very badly on shutdown. We already had one similar Will Not Fix some time ago. The game just crashes because of unhanded exception.

Actually, I think the only way to deal with this is to throw a fatal error instead of a recoverable one. This clearly throws the engine into an unrecoverable state so such an action seems appropriate. Just eating the exception and continue as if nothing happened is not a solution.

The exception is caught during destruction from DThinker::DestroyAllThinkers(). The engine gives up but tries do the same next frame.
Wrapping DestroyThinkersInList() calls with try/catch won't help much. The game will no longer enters an infinite loop but it's still quite useless as VM abort happens on any attempt to start a new game.
I think proper solution is to destroy objects regardless of exception in this particular situation.

This looks like some handler is catching the exception and does not properly forward it...

Pretty much what it says on the thread title. To be specific, the game will go on an infinite loop of VM aborts if you cause a VM abort in Powerup.EndEffect when starting a new game.
Weirdly enough, it'll still render and the process won't stop responding, though it won't respond to any player input at all.

Here's a screenshot, just to show off how weird this bug is:


Steps to reproduce: