asyncio: enhance protocol representation

Add "closed" or "closing" to repr() of selector and proactor transports

Lib/asyncio/proactor_events.py

@@ -42,7 +42,13 @@ class _ProactorBasePipeTransport(transports._FlowControlMixin,
             self._loop.call_soon(waiter._set_result_unless_cancelled, None)
 
     def __repr__(self):
-        info = [self.__class__.__name__, 'fd=%s' % self._sock.fileno()]
+        info = [self.__class__.__name__]
+        fd = self._sock.fileno()
+        if fd < 0:
+            info.append('closed')
+        elif self._closing:
+            info.append('closing')
+        info.append('fd=%s' % fd)
         if self._read_fut is not None:
             info.append('read=%s' % self._read_fut)
         if self._write_fut is not None:

Lib/asyncio/selector_events.py

@@ -467,7 +467,12 @@ class _SelectorTransport(transports._FlowControlMixin,
             self._server._attach()
 
     def __repr__(self):
-        info = [self.__class__.__name__, 'fd=%s' % self._sock_fd]
+        info = [self.__class__.__name__]
+        if self._sock is None:
+            info.append('closed')
+        elif self._closing:
+            info.append('closing')
+        info.append('fd=%s' % self._sock_fd)
         # test if the transport was closed
         if self._loop is not None:
             polling = _test_selector_event(self._loop._selector,