Use newer versions of futures that adds exception tracebacks

Depends-On: I36f1241b983f6552d8bd0471e6a7485532a95a14

Change-Id: I49899019c4a1683bc6664cf0a52dcd5151b6e282

taskflow/tests/unit/test_utils_async_utils.py

@@ -74,13 +74,6 @@ class MakeCompletedFutureTest(test.TestCase):
         self.assertTrue(future.done())
         self.assertIs(future.result(), result)
 
-    def test_make_completed_future_exception(self):
-        result = IOError("broken")
-        future = au.make_completed_future(result, exception=True)
-        self.assertTrue(future.done())
-        self.assertRaises(IOError, future.result)
-        self.assertIsNotNone(future.exception())
-
 
 class AsyncUtilsSynchronousTest(test.TestCase,
                                 WaitForAnyTestsMixin):

taskflow/types/futures.py

@@ -15,6 +15,7 @@
 #    under the License.
 
 import functools
+import sys
 import threading
 
 from concurrent import futures as _futures
@@ -22,6 +23,7 @@ from concurrent.futures import process as _process
 from concurrent.futures import thread as _thread
 from oslo_utils import importutils
 from oslo_utils import reflection
+import six
 
 greenpatcher = importutils.try_import('eventlet.patcher')
 greenpool = importutils.try_import('eventlet.greenpool')
@@ -175,8 +177,15 @@ class _WorkItem(object):
             return
         try:
             result = self.fn(*self.args, **self.kwargs)
-        except BaseException as e:
-            self.future.set_exception(e)
+        except BaseException:
+            exc_type, exc_value, exc_tb = sys.exc_info()
+            try:
+                if six.PY2:
+                    self.future.set_exception_info(exc_value, exc_tb)
+                else:
+                    self.future.set_exception(exc_value)
+            finally:
+                del(exc_type, exc_value, exc_tb)
         else:
             self.future.set_result(result)
 

taskflow/utils/async_utils.py

@@ -30,13 +30,10 @@ _DONE_STATES = frozenset([
 ])
 
 
-def make_completed_future(result, exception=False):
-    """Make a future completed with a given result."""
+def make_completed_future(result):
+    """Make and return a future completed with a given result."""
     future = futures.Future()
-    if exception:
-        future.set_exception(result)
-    else:
-        future.set_result(result)
+    future.set_result(result)
     return future