[Scummvm-tracker] [ScummVM :: Bugs] #17340: COMMON: "Return to the Launcher" GUI option don't work with some games

[ScummVM :: Bugs]

#17340: COMMON: "Return to the Launcher" GUI option don't work with some games
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Reporter:  LukasThyWalls                         |       Owner:  (none)
    Type:  defect                                |      Status:  new
Priority:  normal                                |   Component:  Common
 Version:                                        |  Resolution:
Keywords:  PhoenixVR, Darkseed, GUI, Return to   |        Game:  Darkseed
  Launcher                                       |
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Comment (by criezy):

 The root of the issue comes from commit
 895c665654660584c652623eafea60bdee9fc1ca that causes engines to both post
 a QUIT event and to quit immediately. As a result there is un unprocessed
 quit event when the games returns to the launcher that causes ScummVM to
 quit immediately.

 The engine should only do one thing or the other (set the quit flag
 immediately or post the QUIT event). And normally it should be the latter
 so that it can properly respect the GUI setting to ask for confirmation.

 I don't really understand why the change in the commit above was made. But
 I reluctant to revert it since it was already reverted once and reapplied
 afterward. It looks like we may need to set of functions in the `Engine`
 class, one that sets the quit flag immediately and should only be used by
 engines that have their own confirmation dialog, and one that uses the
 QUIT event. Or else all engines should properly process event after
 calling `quitGame()` so that the should_quit game is properly set (that
 was the original intended behaviour of `quitGame()`.

 One easy "fix" for the issue reported in this ticker would be to purge the
 quit event at the same time we purge input events after quitting a game.
 But that is not the proper fix, and games that expect a confirmation
 dialog may still be broken (not showing the confirmation). One additional
 complexity here is that the quit request may come from the game, or may
 come from the backend. In the latter case the event is properly  processed
 and we do get the confirmation dialog. In the former case we do not. The
 AGI games are one such example. On macOS pressing Cmd-Q shows the ScummVM
 confirmation dialog. Pressing Alt-Z does not.
-- 
Ticket URL: <https://bugs.scummvm.org/ticket/17340#comment:2>
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