Issue #28843: Fix asyncio C Task to handle exceptions __traceback__.

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index e048380e984ebb5e5a93227af192c25e19e64397..a18d49ae3741128fe1a8cf4bcbd39cb75f3fb5e4 100644 (file)
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1952,6 +1952,21 @@ class BaseTaskTests:
         self.assertFalse(gather_task.cancelled())
         self.assertEqual(gather_task.result(), [42])
 
+    def test_exception_traceback(self):
+        # See http://bugs.python.org/issue28843
+
+        @asyncio.coroutine
+        def foo():
+            1 / 0
+
+        @asyncio.coroutine
+        def main():
+            task = self.new_task(self.loop, foo())
+            yield  # skip one loop iteration
+            self.assertIsNotNone(task.exception().__traceback__)
+
+        self.loop.run_until_complete(main())
+
     @mock.patch('asyncio.base_events.logger')
     def test_error_in_call_soon(self, m_log):
         def call_soon(callback, *args):

diff --git a/Misc/NEWS b/Misc/NEWS
index 50a446ad9de7c57e06de45312d9a89d1b046682a..97b159722e2078ec568cfaa4ff5f81daac19b18a 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -24,6 +24,8 @@ Library
 - Issue #24142: Reading a corrupt config file left configparser in an
   invalid state.  Original patch by Florian Höch.
 
+- Issue #28843: Fix asyncio C Task to handle exceptions __traceback__.
+
 Tools/Demos
 -----------
 

diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index b65fc02ebd1f1e2f60eafd947ddbeacd4730e461..4e8f74a3c94ebfc47cb638fb55d0e53caa5cc73c 100644 (file)
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -1042,6 +1042,8 @@ FutureIter_throw(futureiterobject *self, PyObject *args)
 
     if (PyExceptionClass_Check(type)) {
         PyErr_NormalizeException(&type, &val, &tb);
+        /* No need to call PyException_SetTraceback since we'll be calling
+           PyErr_Restore for `type`, `val`, and `tb`. */
     } else if (PyExceptionInstance_Check(type)) {
         if (val) {
             PyErr_SetString(PyExc_TypeError,
@@ -2003,6 +2005,9 @@ task_step_impl(TaskObj *task, PyObject *exc)
         if (!ev || !PyObject_TypeCheck(ev, (PyTypeObject *) et)) {
             PyErr_NormalizeException(&et, &ev, &tb);
         }
+        if (tb != NULL) {
+            PyException_SetTraceback(ev, tb);
+        }
         o = future_set_exception((FutureObj*)task, ev);
         if (!o) {
             /* An exception in Task.set_exception() */