connection: replace select by poll to support fds higher than 1024

Author: Niv Yehezkel

aiopg/connection.py

@@ -110,7 +110,10 @@ def _ready(weak_self):
         except (psycopg2.Warning, psycopg2.Error) as exc:
             if self._fileno is not None:
                 try:
-                    select.select([self._fileno], [], [], 0)
+                    poll = select.poll()
+                    poll.register(self._fileno)
+                    poll.poll(0)
+                    poll.unregister()
                 except OSError as os_exc:
                     if _is_bad_descriptor_error(os_exc):
                         with contextlib.suppress(OSError):

tests/test_connection.py

@@ -642,3 +642,25 @@ async def test_connection_on_server_restart(connect, pg_server, docker):
             delay *= 2
     else:
         pytest.fail("Cannot connect to the restarted server")
+
+
+async def test_no_poll_error_on_high_fd(connect):
+    # The connection file descriptor when higher than 1024 should not raise any
+    # further exception when OperationalError is raised
+    conn = await connect()
+    high_fd = 1025
+
+    impl = mock.Mock()
+    exc = psycopg2.OperationalError('Test')
+    impl.poll.side_effect = exc
+    conn._conn = impl
+    conn._fileno = high_fd
+
+    m_remove_reader = mock.Mock()
+    conn._loop.remove_reader = m_remove_reader
+
+    conn._ready(conn._weakref)
+    assert not m_remove_reader.called
+
+    conn.close()
+    assert m_remove_reader.called_with(high_fd)