Fix issue #29688 by cleaning up after ourselves

chrisjbillington · chrisjbillington · commit 8d2c1c4e8846 · 2025-06-24T13:40:29.000+10:00
Objects without a parent are not necessarily cleaned up in PyQt when
their reference count reaches zero, and must be explicitly cleaned up
with `deleteLater()`

This prevents the notifier firing after the signal handling was supposed
to have been reset to its previous state.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1655,6 +1655,7 @@ def save_args_and_handle_sigint(*args):
     finally:
         wsock.close()
         rsock.close()
+        notifier.deleteLater()
         signal.set_wakeup_fd(old_wakeup_fd)
         signal.signal(signal.SIGINT, old_sigint_handler)
         if handler_args is not None:
