Merge pull request matplotlib#27926 from meeseeksmachine/auto-backport-of-pr-27875-on-v3.8.x

Backport PR matplotlib#27875 on branch v3.8.x (macosx: Clean up single-shot timers correctly)

Author: QuLogic

lib/matplotlib/backends/backend_macosx.py

@@ -64,13 +64,9 @@ def draw_idle(self):
 
     def _single_shot_timer(self, callback):
         """Add a single shot timer with the given callback"""
-        # We need to explicitly stop and remove the timer after
-        # firing, otherwise segfaults will occur when trying to deallocate
-        # the singleshot timers.
         def callback_func(callback, timer):
             callback()
             self._timers.remove(timer)
-            timer.stop()
         timer = self.new_timer(interval=0)
         timer.single_shot = True
         timer.add_callback(callback_func, callback, timer)

src/_macosx.m

@@ -1741,6 +1741,11 @@ - (void)flagsChanged:(NSEvent *)event
                                          repeats: !single
                                            block: ^(NSTimer *timer) {
         gil_call_method((PyObject*)self, "_on_timer");
+        if (single) {
+            // A single-shot timer will be automatically invalidated when it fires, so
+            // we shouldn't do it ourselves when the object is deleted.
+            self->timer = NULL;
+        }
     }];
     // Schedule the timer on the main run loop which is needed
     // when updating the UI from a background thread