From 68e5c2a95f07c5d4d2c33b69528a02b89a099500 Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <jgbt@protonmail.com>
Date: Wed, 14 Oct 2020 12:51:41 -0400
Subject: [PATCH] Raise from asyncio error; fixes mypy

---
 tractor/to_asyncio.py | 50 +++++++++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/tractor/to_asyncio.py b/tractor/to_asyncio.py
index 59db280..85600d7 100644
--- a/tractor/to_asyncio.py
+++ b/tractor/to_asyncio.py
@@ -6,7 +6,7 @@ import inspect
 from typing import (
     Any,
     Callable,
-    AsyncGenerator,
+    AsyncIterator,
     Awaitable,
     Union,
 )
@@ -33,7 +33,7 @@ async def run_coro(
 
 async def consume_asyncgen(
     to_trio: trio.MemorySendChannel,
-    coro: AsyncGenerator,
+    coro: AsyncIterator,
 ) -> None:
     """Stream async generator results back to ``trio``.
 
@@ -50,7 +50,7 @@ async def run_task(
     qsize: int = 2**10,
     _treat_as_stream: bool = False,
     **kwargs,
-) -> Union[AsyncGenerator, Any]:
+) -> Any:
     """Run an ``asyncio`` async function or generator in a task, return
     or stream the result back to ``trio``.
     """
@@ -79,50 +79,58 @@ async def run_task(
     cancel_scope = trio.CancelScope()
 
     # start the asyncio task we submitted from trio
-    # TODO: try out ``anyio`` asyncio based tg here
     if inspect.isawaitable(coro):
         task = asyncio.create_task(run_coro(to_trio, coro))
     elif inspect.isasyncgen(coro):
         task = asyncio.create_task(consume_asyncgen(to_trio, coro))
     else:
-        raise TypeError(f"No support for {coro}")
+        raise TypeError(f"No support for invoking {coro}")
 
-    err = None
+    aio_err = None
 
     def cancel_trio(task):
         """Cancel the calling ``trio`` task on error.
         """
         nonlocal err
-        err = task.exception()
-        if err:
-            log.exception(f"asyncio task errorred:\n{err}")
+        aio_err = task.exception()
+        if aio_err:
+            log.exception(f"asyncio task errorred:\n{aio_err}")
         cancel_scope.cancel()
 
     task.add_done_callback(cancel_trio)
 
-    # asycn gen
+    # async iterator
     if inspect.isasyncgen(coro) or _treat_as_stream:
 
         async def stream_results():
-            with cancel_scope:
-                # stream values upward
-                async with from_aio:
-                    async for item in from_aio:
-                        yield item
-            if cancel_scope.cancelled_caught and err:
-                raise err
+            try:
+                with cancel_scope:
+                    # stream values upward
+                    async with from_aio:
+                        async for item in from_aio:
+                            yield item
+            except BaseException as err:
+                if aio_err is not None:
+                    # always raise from any captured asyncio error
+                    raise err from aio_err
+                else:
+                    raise
 
         return stream_results()
 
     # simple async func
-    elif inspect.iscoroutine(coro):
-
+    try:
         with cancel_scope:
             # return single value
             return await from_aio.receive()
-        if cancel_scope.cancelled_caught and err:
-            raise err
 
+    # Do we need this?
+    except BaseException as err:
+        if aio_err is not None:
+            # always raise from any captured asyncio error
+            raise err from aio_err
+        else:
+            raise
 
 
 def run_as_asyncio_guest(