Handle when SO_REUSEPORT isn't properly supported

Author: SethMichaelLarson

asyncio/base_events.py

@@ -877,8 +877,13 @@ def create_datagram_endpoint(self, protocol_factory,
                             raise ValueError(
                                 'reuse_port not supported by socket module')
                         else:
-                            sock.setsockopt(
-                                socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
+                            try:
+                                sock.setsockopt(
+                                    socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
+                            except OSError:
+                                raise ValueError((
+                                    'reuse_port not supported by socket module, '
+                                    'SO_REUSEPORT defined but not implemented.'))
                     if allow_broadcast:
                         sock.setsockopt(
                             socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
@@ -1005,8 +1010,13 @@ def create_server(self, protocol_factory, host=None, port=None,
                             raise ValueError(
                                 'reuse_port not supported by socket module')
                         else:
-                            sock.setsockopt(
-                                socket.SOL_SOCKET, socket.SO_REUSEPORT, True)
+                            try:
+                                sock.setsockopt(
+                                    socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
+                            except OSError:
+                                raise ValueError((
+                                    'reuse_port not supported by socket module, '
+                                    'SO_REUSEPORT defined but not implemented.'))
                     # Disable IPv4/IPv6 dual stack support (enabled by
                     # default on Linux) which makes a single socket
                     # listen on both address families.

tests/test_base_events.py

@@ -1370,6 +1370,17 @@ def test_create_server_nosoreuseport(self, m_socket):
 
         self.assertRaises(ValueError, self.loop.run_until_complete, f)
 
+    @patch_socket
+    def test_create_server_soreuseport_only_defined(self, m_socket):
+        m_socket.getaddrinfo = socket.getaddrinfo
+        m_socket.socket.return_value = mock.Mock()
+        m_socket.SO_REUSEPORT = -1
+
+        f = self.loop.create_server(
+            MyProto, '0.0.0.0', 0, reuse_port=True)
+
+        self.assertRaises(ValueError, self.loop.run_until_complete, f)
+
     @patch_socket
     def test_create_server_cant_bind(self, m_socket):