Align exceptions between py3 and python

Summary:
- During connection establishment if Thrift python receives a C++ exception it simply throws it. This shows up as RuntimeError in python
 - Thirft-py3 used to gracefully convert C++ exceptions to python exceptions using a function
 - Use the same function in thrift python to align exceptions.

Reviewed By: ahilger

Differential Revision: D75506095

fbshipit-source-id: 0da292d2d210fe14e95a7bc7c006f1b35b4050ce

Author: Vishwa Prakash Gayasen

thrift/lib/py3/test/auto_migrate/clients.py

@@ -118,7 +118,6 @@ async def test_none_arguments(self) -> None:
                     easy(),
                 )
 
-    @brokenInAutoMigrate()
     def test_bad_unix_domain_socket_raises_TransportError_on_connection(self) -> None:
         with tempfile.TemporaryDirectory() as tempdir, socket.socket(
             socket.AF_UNIX, socket.SOCK_STREAM
@@ -131,7 +130,6 @@ async def connect_to_unlistened_socket() -> None:
                     pass
 
             loop = asyncio.get_event_loop()
-            # thrift-python raises RuntimeError from AsyncSocketException
             with self.assertRaises(TransportError) as cm:
                 loop.run_until_complete(connect_to_unlistened_socket())
             ex = cm.exception

thrift/lib/python/client/async_client_factory.pyx

@@ -26,6 +26,7 @@ from cython.operator cimport dereference as deref
 from folly.futures cimport bridgeFutureWith
 from libc.stdint cimport uint32_t
 from libcpp.memory cimport make_shared, static_pointer_cast
+from thrift.python.exceptions cimport create_py_exception
 from libcpp.string cimport string
 from libcpp.utility cimport move as cmove
 from thrift.python.client.async_client cimport AsyncClient
@@ -253,10 +254,7 @@ cdef void requestchannel_callback(
     cdef AsyncClient client = <object> userData
     future = client._connect_future
     if result.hasException():
-        try:
-            result.exception().throw_exception()
-        except Exception as pyex:
-            future.set_exception(pyex)
+        future.set_exception(create_py_exception(result.exception(), None))
     else:
         client.bind_client(cmove(result.value()))
         future.set_result(None)