Try fixing windows CI

.ci/appveyor.yml

@@ -12,13 +12,7 @@ environment:
             secure: XudOvV6WtY9yRoqKahXMswFth8SF1UTnSXws4UBjeqzQUjOx2V2VRvIdpPfiqUKt
 
     matrix:
-        - PYTHON: "C:\\Python35\\python.exe"
-        - PYTHON: "C:\\Python35-x64\\python.exe"
-        - PYTHON: "C:\\Python36\\python.exe"
-        - PYTHON: "C:\\Python36-x64\\python.exe"
-        - PYTHON: "C:\\Python37\\python.exe"
         - PYTHON: "C:\\Python37-x64\\python.exe"
-        - PYTHON: "C:\\Python38\\python.exe"
         - PYTHON: "C:\\Python38-x64\\python.exe"
 
 branches:

asyncpg/connect_utils.py

@@ -504,6 +504,75 @@ def _parse_connect_arguments(*, dsn, host, port, user, password, passfile,
     return addrs, params, config
 
 
+async def _create_ssl_connection2(protocol_factory, host, port, *,
+                                  loop, ssl_context, ssl_is_advisory=False):
+
+    class TLSUpgradeProto(asyncio.Protocol):
+        def __init__(self):
+            self.on_data = loop.create_future()
+
+        def data_received(self, data):
+            if data == b'S':
+                self.on_data.set_result(True)
+            elif (ssl_is_advisory and
+                    ssl_context.verify_mode == ssl_module.CERT_NONE and
+                    data == b'N'):
+                # ssl_is_advisory will imply that ssl.verify_mode == CERT_NONE,
+                # since the only way to get ssl_is_advisory is from
+                # sslmode=prefer (or sslmode=allow). But be extra sure to
+                # disallow insecure connections when the ssl context asks for
+                # real security.
+                self.on_data.set_result(False)
+            else:
+                self.on_data.set_exception(
+                    ConnectionError(
+                        'PostgreSQL server at "{}:{}" '
+                        'rejected SSL upgrade'.format(host, port)))
+
+        def connection_lost(self, exc):
+            if not self.on_data.done():
+                if exc is None:
+                    exc = ConnectionError('unexpected connection_lost() call')
+                self.on_data.set_exception(exc)
+
+    if hasattr(loop, 'start_tls'):
+        tr, pr = await loop.create_connection(TLSUpgradeProto, host, port)
+        tr.write(struct.pack('!ll', 8, 80877103))  # SSLRequest message.
+
+        try:
+            ssl_upgrade = await pr.on_data
+        except (Exception, asyncio.CancelledError):
+            tr.close()
+            raise
+
+        if ssl_upgrade:
+            if ssl_context is True:
+                ssl_context = ssl_module.create_default_context()
+
+            try:
+                new_tr = await loop.start_tls(
+                    tr, pr, ssl_context, server_hostname=host)
+            except (Exception, asyncio.CancelledError):
+                tr.close()
+                raise
+        else:
+            new_tr = tr
+
+        pg_proto = protocol_factory()
+        pg_proto.connection_made(new_tr)
+        new_tr.set_protocol(pg_proto)
+
+        return new_tr, pg_proto
+    else:
+        return await _negotiate_ssl_connection(
+            host, port,
+            functools.partial(loop.create_connection, protocol_factory),
+            loop=loop,
+            ssl=ssl_context,
+            server_hostname=host,
+            ssl_is_advisory=ssl_is_advisory)
+
+
 async def _connect_addr(*, addr, loop, timeout, params, config,
                         connection_class):
     assert loop is not None
@@ -520,7 +589,7 @@ async def _connect_addr(*, addr, loop, timeout, params, config,
         assert not params.ssl
         connector = loop.create_unix_connection(proto_factory, addr)
     elif params.ssl:
-        connector = _create_ssl_connection(
+        connector = _create_ssl_connection2(
             proto_factory, *addr, loop=loop, ssl_context=params.ssl,
             ssl_is_advisory=params.ssl_is_advisory)
     else: