Add big fat (but not fat or scary enough) warnings about save corruption.

On a modern computer, crawl tends to process commands fast enough that
closing the game is likely to happen during some waiting for event loop,
and thus typically not cause not cause a lock-up or memory corruption
but "merely" allow cheating.  This is not acceptable, and once in a while
you get more classical results of doing naughty stuff from a signal
handler.

One way of fixing this would be setting a flag (seen_hups) and killing
any functions that wait for an event.  This can be tricky because:

* ncurses like to sabotage EINTR.  We need to abort it both on SIGHUP
  and on SIGWINCH, without race conditions.  The documentation says
  SIGWINCH is supposed to return a pseudo key code, KEY_RESIZE but
  this doesn't seem to be working.  Not sure how to abort it on HUP.

* win32's console functions don't have an equivalent to EINTR.  Perhaps
  injecting a fake key with WriteConsoleInput would work?

* same for tiles and Android.

* yesno() without a safeanswer will loop forever

1 files changed, 7 insertions, 0 deletions

diff --git a/crawl-ref/source/tilesdl.cc b/crawl-ref/source/tilesdl.cc
index 62c6097518..a83c152f12 100644
--- a/crawl-ref/source/tilesdl.cc
+++ b/crawl-ref/source/tilesdl.cc
@@ -699,6 +699,11 @@ int TilesFramework::getch_ck()
                 // close it
                 if (/*event.active.state == 0x04 SDL_APPACTIVE &&*/ event.active.gain == 0)
                 {
+                    // SAVE-CORRUPTING BUG!!! We're likely in a place that may
+                    // have an inconsistent state, or at least allows cheating
+                    // by forcing a save in the middle of some processing.
+                    // This must set a flag, kill all waits then continue
+                    // until a graceful shutdown.
                     if (crawl_state.need_save)
                         save_game(true);
                     exit(0);
@@ -819,6 +824,8 @@ int TilesFramework::getch_ck()
                 break;
 
             case WME_QUIT:
+                // SAVE-CORRUPTING BUG!!! This must not save here, but set
+                // a flag, disable all waits and allow a graceful shutdown.
                 if (crawl_state.need_save)
                     save_game(true);
                 exit(0);