Fix bot crashing in !frestart

This fixes the bug where bot would crash on endgame through faftergame
without sending all messages, but introduces a new bug where someone can
quit between endgame and the bot's own quit, crashing it. This is an
extremely tight race condition, and shouldn't matter most of the time.
Further explanation in the big wall of text.

src/wolfgame.py

@@ -581,14 +581,44 @@ def restart_program(cli, nick, chan, rest):
     except Exception:
         notify_error(cli, chan, errlog)
 
-    plog("RESTARTING")
+    @hook("quit")
+    def restart_buffer(*s):
+        # *** BIG FLASHY RED WARNING GOES HERE ***
+        # THERE IS A POTENTIAL RACE CONDITION IN THIS CODE
 
-    python = sys.executable
+        # this is due to the fact that the socket's buffer is not empty
+        # when we reach the os.execl calls, so we kill the process before
+        # the buffer is done being sent. someone who knows better than me
+        # at sockets should probably try to fix this properly. for now, this
+        # is actually a working fix; we want to wait until the above quit
+        # call is processed (we see our own quit). I prefer false positives
+        # over false negatives, so I'd rather have this hook trigger on more
+        # quits than not enough. the race condition mentioned above happens
+        # if someone else quits while the bot is still sending data. I haven't
+        # actually tested this to see if it processes received data even if
+        # it's currently sending stuff, thus why it's a "potential" race
+        # condition anyway. I'm fairly sure we can, though, so this is a
+        # bug. however this is a rare bug and would cause annoyance only in
+        # some times, while the previous behaviour caused annoyance at all
+        # times, since the process was killed before all the buffering could
+        # be processed. should this happen, the bot was waiting for its own
+        # quit to restart anyway, so it's not restarting while nothing was
+        # supposed to happen. this isn't a critical bug (I hear you woffle,
+        # yes we should fix it better, but this is also less worse than it
+        # used to be, any upside is good to take; if we can't fix it in one
+        # go better to at least fix what we can), but a bug nonetheless, and
+        # should be fixed as soon as someone finds a proper fix. -Vgr
 
-    if mode:
-        os.execl(python, python, sys.argv[0], "--{0}".format(mode))
-    else:
-        os.execl(python, python, *sys.argv)
+        # TL;DR - data does not finish sending before we kill the process
+
+        plog("RESTARTING")
+
+        python = sys.executable
+
+        if mode:
+            os.execl(python, python, sys.argv[0], "--{0}".format(mode))
+        else:
+            os.execl(python, python, *sys.argv)
 
 
 @cmd("ping", chan=False, pm=True)