bpo-32193: Convert asyncio to async/await usage (#4753)

* Convert asyncio/tasks.py to async/await

* Convert asyncio/queues.py to async/await

* Convert asyncio/test_utils.py to async/await

* Convert asyncio/base_subprocess.py to async/await

* Convert asyncio/subprocess.py to async/await

* Convert asyncio/streams.py to async/await

* Fix comments

* Convert asyncio/locks.py to async/await

* Convert asyncio.sleep to async def

* Add a comment

* Add missing news

* Convert stubs from AbstrctEventLoop to async functions

* Convert subprocess_shell/subprocess_exec

* Convert connect_read_pipe/connect_write_pip to async/await syntax

* Convert create_datagram_endpoint

* Convert create_unix_server/create_unix_connection

* Get rid of old style coroutines in unix_events.py

* Convert selector_events.py to async/await

* Convert wait_closed and create_connection

* Drop redundant line

* Convert base_events.py

* Code cleanup

* Drop redundant comments

* Fix indentation

* Add explicit tests for compatibility between old and new coroutines

* Convert windows event loop to use async/await

* Fix double awaiting of async function

* Convert asyncio/locks.py

* Improve docstring

* Convert tests to async/await

* Convert more tests

* Convert more tests

* Convert more tests

* Convert tests

* Improve test

1 files changed, 6 insertions, 9 deletions

diff --git a/Lib/asyncio/base_subprocess.py b/Lib/asyncio/base_subprocess.py
index cac8d96..7e5a901 100644
--- a/Lib/asyncio/base_subprocess.py
+++ b/Lib/asyncio/base_subprocess.py
@@ -4,7 +4,6 @@ import warnings
 
 from . import protocols
 from . import transports
-from .coroutines import coroutine
 from .log import logger
 
 
@@ -154,26 +153,25 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
         self._check_proc()
         self._proc.kill()
 
-    @coroutine
-    def _connect_pipes(self, waiter):
+    async def _connect_pipes(self, waiter):
         try:
             proc = self._proc
             loop = self._loop
 
             if proc.stdin is not None:
-                _, pipe = yield from loop.connect_write_pipe(
+                _, pipe = await loop.connect_write_pipe(
                     lambda: WriteSubprocessPipeProto(self, 0),
                     proc.stdin)
                 self._pipes[0] = pipe
 
             if proc.stdout is not None:
-                _, pipe = yield from loop.connect_read_pipe(
+                _, pipe = await loop.connect_read_pipe(
                     lambda: ReadSubprocessPipeProto(self, 1),
                     proc.stdout)
                 self._pipes[1] = pipe
 
             if proc.stderr is not None:
-                _, pipe = yield from loop.connect_read_pipe(
+                _, pipe = await loop.connect_read_pipe(
                     lambda: ReadSubprocessPipeProto(self, 2),
                     proc.stderr)
                 self._pipes[2] = pipe
@@ -224,8 +222,7 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
                 waiter.set_result(returncode)
         self._exit_waiters = None
 
-    @coroutine
-    def _wait(self):
+    async def _wait(self):
         """Wait until the process exit and return the process return code.
 
         This method is a coroutine."""
@@ -234,7 +231,7 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
 
         waiter = self._loop.create_future()
         self._exit_waiters.append(waiter)
-        return (yield from waiter)
+        return await waiter
 
     def _try_finish(self):
         assert not self._finished