From ac634d71f4cc75946012e51f955c6f5292da2aee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Skytt=C3=A4?= <ville.skytta@iki.fi>
Date: Sat, 28 Sep 2019 03:02:48 +0300
Subject: [PATCH] Remove no longer needed Python < 3.6 compatibility code
 (#27024)

---
 homeassistant/util/async_.py | 130 +----------------------------------
 1 file changed, 3 insertions(+), 127 deletions(-)

diff --git a/homeassistant/util/async_.py b/homeassistant/util/async_.py
index d43658d1584..6920e0d97f6 100644
--- a/homeassistant/util/async_.py
+++ b/homeassistant/util/async_.py
@@ -1,23 +1,13 @@
-"""Asyncio backports for Python 3.4.3 compatibility."""
+"""Asyncio backports for Python 3.6 compatibility."""
 import concurrent.futures
 import threading
 import logging
 from asyncio import coroutines
 from asyncio.events import AbstractEventLoop
-from asyncio.futures import Future
 
 import asyncio
 from asyncio import ensure_future
-from typing import (
-    Any,
-    Union,
-    Coroutine,
-    Callable,
-    Generator,
-    TypeVar,
-    Awaitable,
-    Optional,
-)
+from typing import Any, Union, Coroutine, Callable, Generator, TypeVar, Awaitable
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -40,105 +30,6 @@ except AttributeError:
             loop.close()
 
 
-def _set_result_unless_cancelled(fut: Future, result: Any) -> None:
-    """Set the result only if the Future was not cancelled."""
-    if fut.cancelled():
-        return
-    fut.set_result(result)
-
-
-def _set_concurrent_future_state(
-    concurr: concurrent.futures.Future, source: Union[concurrent.futures.Future, Future]
-) -> None:
-    """Copy state from a future to a concurrent.futures.Future."""
-    assert source.done()
-    if source.cancelled():
-        concurr.cancel()
-    if not concurr.set_running_or_notify_cancel():
-        return
-    exception = source.exception()
-    if exception is not None:
-        concurr.set_exception(exception)
-    else:
-        result = source.result()
-        concurr.set_result(result)
-
-
-def _copy_future_state(
-    source: Union[concurrent.futures.Future, Future],
-    dest: Union[concurrent.futures.Future, Future],
-) -> None:
-    """Copy state from another Future.
-
-    The other Future may be a concurrent.futures.Future.
-    """
-    assert source.done()
-    if dest.cancelled():
-        return
-    assert not dest.done()
-    if source.cancelled():
-        dest.cancel()
-    else:
-        exception = source.exception()
-        if exception is not None:
-            dest.set_exception(exception)
-        else:
-            result = source.result()
-            dest.set_result(result)
-
-
-def _chain_future(
-    source: Union[concurrent.futures.Future, Future],
-    destination: Union[concurrent.futures.Future, Future],
-) -> None:
-    """Chain two futures so that when one completes, so does the other.
-
-    The result (or exception) of source will be copied to destination.
-    If destination is cancelled, source gets cancelled too.
-    Compatible with both asyncio.Future and concurrent.futures.Future.
-    """
-    if not isinstance(source, (Future, concurrent.futures.Future)):
-        raise TypeError("A future is required for source argument")
-    if not isinstance(destination, (Future, concurrent.futures.Future)):
-        raise TypeError("A future is required for destination argument")
-    # pylint: disable=protected-access
-    if isinstance(source, Future):
-        source_loop: Optional[AbstractEventLoop] = source._loop
-    else:
-        source_loop = None
-    if isinstance(destination, Future):
-        dest_loop: Optional[AbstractEventLoop] = destination._loop
-    else:
-        dest_loop = None
-
-    def _set_state(
-        future: Union[concurrent.futures.Future, Future],
-        other: Union[concurrent.futures.Future, Future],
-    ) -> None:
-        if isinstance(future, Future):
-            _copy_future_state(other, future)
-        else:
-            _set_concurrent_future_state(future, other)
-
-    def _call_check_cancel(
-        destination: Union[concurrent.futures.Future, Future]
-    ) -> None:
-        if destination.cancelled():
-            if source_loop is None or source_loop is dest_loop:
-                source.cancel()
-            else:
-                source_loop.call_soon_threadsafe(source.cancel)
-
-    def _call_set_state(source: Union[concurrent.futures.Future, Future]) -> None:
-        if dest_loop is None or dest_loop is source_loop:
-            _set_state(destination, source)
-        else:
-            dest_loop.call_soon_threadsafe(_set_state, destination, source)
-
-    destination.add_done_callback(_call_check_cancel)
-    source.add_done_callback(_call_set_state)
-
-
 def run_coroutine_threadsafe(
     coro: Union[Coroutine, Generator], loop: AbstractEventLoop
 ) -> concurrent.futures.Future:
@@ -150,22 +41,7 @@ def run_coroutine_threadsafe(
     if ident is not None and ident == threading.get_ident():
         raise RuntimeError("Cannot be called from within the event loop")
 
-    if not coroutines.iscoroutine(coro):
-        raise TypeError("A coroutine object is required")
-    future: concurrent.futures.Future = concurrent.futures.Future()
-
-    def callback() -> None:
-        """Handle the call to the coroutine."""
-        try:
-            _chain_future(ensure_future(coro, loop=loop), future)
-        except Exception as exc:  # pylint: disable=broad-except
-            if future.set_running_or_notify_cancel():
-                future.set_exception(exc)
-            else:
-                _LOGGER.warning("Exception on lost future: ", exc_info=True)
-
-    loop.call_soon_threadsafe(callback)
-    return future
+    return asyncio.run_coroutine_threadsafe(coro, loop)
 
 
 def fire_coroutine_threadsafe(coro: Coroutine, loop: AbstractEventLoop) -> None: