run CFRunLoopRun if NSApp:run finishes on its own

this seems to happen when the last Window is closed,
but the eventloop needs to run a little longer in order to finish closing the Window

IPython/terminal/pt_inputhooks/osx.py

@@ -7,6 +7,7 b' Calls NSApp / CoreFoundation APIs via ctypes.'
 
 import ctypes
 import ctypes.util
+from threading import Event
 
 objc = ctypes.cdll.LoadLibrary(ctypes.util.find_library('objc'))
 
@@ -97,8 +98,11 b' def _wake(NSApp):'
     msg(NSApp, n('postEvent:atStart:'), void_p(event), True)
 
 
+_triggered = Event()
+
 def _input_callback(fdref, flags, info):
     """Callback to fire when there's input to be read"""
+    _triggered.set()
     CFFileDescriptorInvalidate(fdref)
     CFRelease(fdref)
     NSApp = _NSApp()
@@ -111,6 +115,7 b' _c_input_callback = _c_callback_func_type(_input_callback)'
 
 def _stop_on_read(fd):
     """Register callback to stop eventloop when there's data on fd"""
+    _triggered.clear()
     fdref = CFFileDescriptorCreate(None, fd, False, _c_input_callback, None)
     CFFileDescriptorEnableCallBacks(fdref, kCFFileDescriptorReadCallBack)
     source = CFFileDescriptorCreateRunLoopSource(None, fdref, 0)
@@ -130,4 +135,9 b' def inputhook(context):'
         return
     _stop_on_read(context.fileno())
     msg(NSApp, n('run'))
-
+    if not _triggered.is_set():
+        # app closed without firing callback,
+        # probably due to last window being closed.
+        # Run the loop manually in this case,
+        # since there may be events still to process (#9734)
+        CoreFoundation.CFRunLoopRun()