fix: ensure hub close does also remove global event loop reference

kombu/asynchronous/hub.py

@@ -256,6 +256,7 @@ def _pop_ready(self):
             return ready
 
     def close(self, *args):
+        global _current_loop
         [self._unregister(fd) for fd in self.readers]
         self.readers.clear()
         [self._unregister(fd) for fd in self.writers]
@@ -274,6 +275,10 @@ def close(self, *args):
         for item in todos:
             item()
 
+        # Clear global event loop variable if this hub is the current loop
+        if _current_loop is self:
+            set_event_loop(None)
+
     def _discard(self, fd):
         fd = fileno(fd)
         self.readers.pop(fd, None)

t/unit/asynchronous/test_hub.py

@@ -586,3 +586,30 @@ def test__pop_ready_uses_lock(self):
         with patch.object(self.hub, '_ready_lock', autospec=True) as lock:
             self.hub._pop_ready()
             lock.__enter__.assert_called_once()
+
+    def test_close_clears_global_event_loop(self):
+        # Test that closing a hub clears the global event loop if it's the current one
+        prev_loop = get_event_loop()
+        try:
+            hub = Hub()
+            set_event_loop(hub)
+            assert get_event_loop() is hub
+            hub.close()
+            assert get_event_loop() is None
+        finally:
+            set_event_loop(prev_loop)
+
+    def test_close_does_not_clear_other_event_loop(self):
+        # Test that closing a hub doesn't clear the global event loop if it's a different one
+        prev_loop = get_event_loop()
+        try:
+            hub1 = Hub()
+            hub2 = Hub()
+            set_event_loop(hub1)
+            assert get_event_loop() is hub1
+            hub2.close()
+            # hub1 should still be the current loop
+            assert get_event_loop() is hub1
+            hub1.close()
+        finally:
+            set_event_loop(prev_loop)