Fix and enable no-member lint

.pylintrc

@@ -30,6 +30,5 @@
 #TODO: Enable too-many-nested-blocks
 #TODO: Enable super-init-not-called
 #TODO: Enable no-self-use
-#TODO: Enable no-member
 
-disable=missing-docstring,too-few-public-methods,too-many-arguments,no-init,duplicate-code,invalid-name,suppressed-message,locally-disabled,protected-access,no-name-in-module,unused-argument,fixme,wrong-import-order,no-value-for-parameter,cyclic-import,unused-variable,redefined-outer-name,unused-import,too-many-instance-attributes,broad-except,too-many-locals,too-many-lines,redefined-variable-type,next-method-called,import-error,useless-else-on-loop,too-many-return-statements,too-many-nested-blocks,super-init-not-called,no-self-use,no-member
+disable=missing-docstring,too-few-public-methods,too-many-arguments,no-init,duplicate-code,invalid-name,suppressed-message,locally-disabled,protected-access,no-name-in-module,unused-argument,fixme,wrong-import-order,no-value-for-parameter,cyclic-import,unused-variable,redefined-outer-name,unused-import,too-many-instance-attributes,broad-except,too-many-locals,too-many-lines,redefined-variable-type,next-method-called,import-error,useless-else-on-loop,too-many-return-statements,too-many-nested-blocks,super-init-not-called,no-self-use

src/python/grpcio/grpc/_channel.py

@@ -43,7 +43,6 @@ _USER_AGENT = 'Python-gRPC-{}'.format(_grpcio_metadata.__version__)
 
 _EMPTY_FLAGS = 0
 _INFINITE_FUTURE = cygrpc.Timespec(float('+inf'))
-_EMPTY_METADATA = cygrpc.Metadata(())
 
 _UNARY_UNARY_INITIAL_DUE = (cygrpc.OperationType.send_initial_metadata,
                             cygrpc.OperationType.send_message,
@@ -138,8 +137,8 @@ def _abort(state, code, details):
         state.code = code
         state.details = details
         if state.initial_metadata is None:
-            state.initial_metadata = _EMPTY_METADATA
-        state.trailing_metadata = _EMPTY_METADATA
+            state.initial_metadata = _common.EMPTY_METADATA
+        state.trailing_metadata = _common.EMPTY_METADATA
 
 
 def _handle_event(event, state, response_deserializer):
@@ -435,7 +434,7 @@ def _start_unary_request(request, timeout, request_serializer):
     deadline, deadline_timespec = _deadline(timeout)
     serialized_request = _common.serialize(request, request_serializer)
     if serialized_request is None:
-        state = _RPCState((), _EMPTY_METADATA, _EMPTY_METADATA,
+        state = _RPCState((), _common.EMPTY_METADATA, _common.EMPTY_METADATA,
                           grpc.StatusCode.INTERNAL,
                           'Exception serializing request!')
         rendezvous = _Rendezvous(state, None, None, deadline)

src/python/grpcio/grpc/_common.py

@@ -37,7 +37,7 @@ import six
 import grpc
 from grpc._cython import cygrpc
 
-_EMPTY_METADATA = cygrpc.Metadata(())
+EMPTY_METADATA = cygrpc.Metadata(())
 
 CYGRPC_CONNECTIVITY_STATE_TO_CHANNEL_CONNECTIVITY = {
     cygrpc.ConnectivityState.idle:
@@ -107,7 +107,7 @@ def channel_args(options):
 
 
 def cygrpc_metadata(application_metadata):
-    return _EMPTY_METADATA if application_metadata is None else cygrpc.Metadata(
+    return EMPTY_METADATA if application_metadata is None else cygrpc.Metadata(
         cygrpc.Metadatum(encode(key), encode(value))
         for key, value in application_metadata)
 

src/python/grpcio/grpc/_server.py

@@ -57,7 +57,6 @@ _CLOSED = 'closed'
 _CANCELLED = 'cancelled'
 
 _EMPTY_FLAGS = 0
-_EMPTY_METADATA = cygrpc.Metadata(())
 
 _UNEXPECTED_EXIT_SERVER_GRACE = 1.0
 
@@ -143,7 +142,7 @@ def _abort(state, call, code, details):
         effective_details = details if state.details is None else state.details
         if state.initial_metadata_allowed:
             operations = (cygrpc.operation_send_initial_metadata(
-                _EMPTY_METADATA, _EMPTY_FLAGS),
+                _common.EMPTY_METADATA, _EMPTY_FLAGS),
                           cygrpc.operation_send_status_from_server(
                               _common.cygrpc_metadata(state.trailing_metadata),
                               effective_code, effective_details, _EMPTY_FLAGS),)
@@ -416,7 +415,7 @@ def _send_response(rpc_event, state, serialized_response):
         else:
             if state.initial_metadata_allowed:
                 operations = (cygrpc.operation_send_initial_metadata(
-                    _EMPTY_METADATA, _EMPTY_FLAGS),
+                    _common.EMPTY_METADATA, _EMPTY_FLAGS),
                               cygrpc.operation_send_message(serialized_response,
                                                             _EMPTY_FLAGS),)
                 state.initial_metadata_allowed = False
@@ -446,8 +445,8 @@ def _status(rpc_event, state, serialized_response):
             ]
             if state.initial_metadata_allowed:
                 operations.append(
-                    cygrpc.operation_send_initial_metadata(_EMPTY_METADATA,
-                                                           _EMPTY_FLAGS))
+                    cygrpc.operation_send_initial_metadata(
+                        _common.EMPTY_METADATA, _EMPTY_FLAGS))
             if serialized_response is not None:
                 operations.append(
                     cygrpc.operation_send_message(serialized_response,
@@ -549,11 +548,11 @@ def _find_method_handler(rpc_event, generic_handlers):
 
 
 def _handle_unrecognized_method(rpc_event):
-    operations = (
-        cygrpc.operation_send_initial_metadata(_EMPTY_METADATA, _EMPTY_FLAGS),
+    operations = (cygrpc.operation_send_initial_metadata(_common.EMPTY_METADATA,
+                                                         _EMPTY_FLAGS),
                   cygrpc.operation_receive_close_on_server(_EMPTY_FLAGS),
                   cygrpc.operation_send_status_from_server(
-            _EMPTY_METADATA, cygrpc.StatusCode.unimplemented,
+                      _common.EMPTY_METADATA, cygrpc.StatusCode.unimplemented,
                       b'Method not found!', _EMPTY_FLAGS),)
     rpc_state = _RPCState()
     rpc_event.operation_call.start_server_batch(