bpo-35545: Fix asyncio discarding IPv6 scopes (GH-11271)

This PR proposes a solution to [bpo-35545](https://bugs.python.org/issue35545) by adding an optional `flowinfo` and `scopeid` to `asyncio.base_events._ipaddr_info` to carry the full address information into `_ipaddr_info` and avoid discarding IPv6 specific information.

Changelog entry & regression tests to come.


https://bugs.python.org/issue35545

1 files changed, 22 insertions, 0 deletions

diff --git a/Lib/test/test_asyncio/test_base_events.py b/Lib/test/test_asyncio/test_base_events.py
index 27e21b33d3..f068fc781f 100644
--- a/Lib/test/test_asyncio/test_base_events.py
+++ b/Lib/test/test_asyncio/test_base_events.py
@@ -1300,6 +1300,28 @@ class BaseEventLoopWithSelectorTests(test_utils.TestCase):
             test_utils.run_briefly(self.loop)  # allow transport to close
 
     @patch_socket
+    def test_create_connection_ipv6_scope(self, m_socket):
+        m_socket.getaddrinfo = socket.getaddrinfo
+        sock = m_socket.socket.return_value
+        sock.family = socket.AF_INET6
+
+        self.loop._add_reader = mock.Mock()
+        self.loop._add_reader._is_coroutine = False
+        self.loop._add_writer = mock.Mock()
+        self.loop._add_writer._is_coroutine = False
+
+        coro = self.loop.create_connection(asyncio.Protocol, 'fe80::1%1', 80)
+        t, p = self.loop.run_until_complete(coro)
+        try:
+            sock.connect.assert_called_with(('fe80::1', 80, 0, 1))
+            _, kwargs = m_socket.socket.call_args
+            self.assertEqual(kwargs['family'], m_socket.AF_INET6)
+            self.assertEqual(kwargs['type'], m_socket.SOCK_STREAM)
+        finally:
+            t.close()
+            test_utils.run_briefly(self.loop)  # allow transport to close
+
+    @patch_socket
     def test_create_connection_ip_addr(self, m_socket):
         self._test_create_connection_ip_addr(m_socket, True)