better stack trace in run_in_greenlet decorator

pulsar/apps/greenio/utils.py

@@ -1,3 +1,4 @@
+import sys
 from functools import wraps
 from inspect import isawaitable
 
@@ -38,8 +39,9 @@ async def _(*args, **kwargs):
             # keep on switching back to the greenlet if we get a Future
             try:
                 result = green.switch((await result))
-            except Exception as exc:
-                result = green.throw(exc)
+            except Exception:
+                exc_info = sys.exc_info()
+                result = green.throw(*exc_info)
 
         return green.switch(result)
 

tests/apps/test_greenio.py

@@ -1,5 +1,7 @@
+import sys
 import unittest
 import asyncio
+import traceback
 from unittest import mock
 
 from pulsar.api import send, create_future
@@ -168,6 +170,25 @@ def test_green_http(self):
         self.assertEqual(response.status_code, 200)
         self.assertTrue(response.text)
 
+    async def test_run_in_greenlet_error(self):
+
+        def error():
+            return 'foo' + 1
+
+        @run_in_greenlet
+        def green_test():
+            return error()
+
+        try:
+            await green_test()
+        except TypeError:
+            exc = sys.exc_info()
+        else:
+            raise RuntimeError
+        info = traceback.format_tb(exc[2])
+        self.assertEqual(len(info), 4)
+        self.assertTrue(info[3].endswith("return 'foo' + 1\n"))
+
 
 async def async_function(test):
     future = create_future()