Calling debug() on a destroyed libuv loop would raise TypeError

TypeError: initializer for ctype 'struct uv_loop_s *' must be a cdata pointer, not NoneType

Now it is safe.

src/gevent/libuv/loop.py

@@ -397,18 +397,21 @@ class loop(AbstractLoop):
             del self._fork_watchers
             del self._child_watchers
 
-
-    def debug(self):
-        """
-        Return all the handles that are open and their ref status.
-        """
-        handle_state = namedtuple("HandleState",
+    _HandleState = namedtuple("HandleState",
                               ['handle',
                                'type',
                                'watcher',
                                'ref',
                                'active',
                                'closing'])
+    def debug(self):
+        """
+        Return all the handles that are open and their ref status.
+        """
+        if not self.ptr:
+            return ["Loop has been destroyed"]
+
+        handle_state = self._HandleState
         handles = []
 
         # XXX: Convert this to a modern callback.