bpo-36889: Merge asyncio streams (GH-13251)

https://bugs.python.org/issue36889

Lib/asyncio/__init__.py

@@ -3,6 +3,7 @@
 # flake8: noqa
 
 import sys
+import warnings
 
 # This relies on each of the submodules having an __all__ variable.
 from .base_events import *
@@ -43,3 +44,40 @@ if sys.platform == 'win32':  # pragma: no cover
 else:
     from .unix_events import *  # pragma: no cover
     __all__ += unix_events.__all__
+
+
+__all__ += ('StreamReader', 'StreamWriter', 'StreamReaderProtocol')  # deprecated
+
+
+def __getattr__(name):
+    global StreamReader, StreamWriter, StreamReaderProtocol
+    if name == 'StreamReader':
+        warnings.warn("StreamReader is deprecated since Python 3.8 "
+                      "in favor of Stream, and scheduled for removal "
+                      "in Python 3.10",
+                      DeprecationWarning,
+                      stacklevel=2)
+        from .streams import StreamReader as sr
+        StreamReader = sr
+        return StreamReader
+    if name == 'StreamWriter':
+        warnings.warn("StreamWriter is deprecated since Python 3.8 "
+                      "in favor of Stream, and scheduled for removal "
+                      "in Python 3.10",
+                      DeprecationWarning,
+                      stacklevel=2)
+        from .streams import StreamWriter as sw
+        StreamWriter = sw
+        return StreamWriter
+    if name == 'StreamReaderProtocol':
+        warnings.warn("Using asyncio internal class StreamReaderProtocol "
+                      "is deprecated since Python 3.8 "
+                      " and scheduled for removal "
+                      "in Python 3.10",
+                      DeprecationWarning,
+                      stacklevel=2)
+        from .streams import StreamReaderProtocol as srp
+        StreamReaderProtocol = srp
+        return StreamReaderProtocol
+
+    raise AttributeError(f"module {__name__} has no attribute {name}")

Lib/asyncio/subprocess.py

@@ -27,6 +27,8 @@ class SubprocessStreamProtocol(streams.FlowControlMixin,
         self._process_exited = False
         self._pipe_fds = []
         self._stdin_closed = self._loop.create_future()
+        self._stdout_closed = self._loop.create_future()
+        self._stderr_closed = self._loop.create_future()
 
     def __repr__(self):
         info = [self.__class__.__name__]
@@ -40,30 +42,35 @@ class SubprocessStreamProtocol(streams.FlowControlMixin,
 
     def connection_made(self, transport):
         self._transport = transport
-
         stdout_transport = transport.get_pipe_transport(1)
         if stdout_transport is not None:
-            self.stdout = streams.StreamReader(limit=self._limit,
-                                               loop=self._loop,
-                                               _asyncio_internal=True)
+            self.stdout = streams.Stream(mode=streams.StreamMode.READ,
+                                         transport=stdout_transport,
+                                         protocol=self,
+                                         limit=self._limit,
+                                         loop=self._loop,
+                                         _asyncio_internal=True)
             self.stdout.set_transport(stdout_transport)
             self._pipe_fds.append(1)
 
         stderr_transport = transport.get_pipe_transport(2)
         if stderr_transport is not None:
-            self.stderr = streams.StreamReader(limit=self._limit,
-                                               loop=self._loop,
-                                               _asyncio_internal=True)
+            self.stderr = streams.Stream(mode=streams.StreamMode.READ,
+                                         transport=stderr_transport,
+                                         protocol=self,
+                                         limit=self._limit,
+                                         loop=self._loop,
+                                         _asyncio_internal=True)
             self.stderr.set_transport(stderr_transport)
             self._pipe_fds.append(2)
 
         stdin_transport = transport.get_pipe_transport(0)
         if stdin_transport is not None:
-            self.stdin = streams.StreamWriter(stdin_transport,
-                                              protocol=self,
-                                              reader=None,
-                                              loop=self._loop,
-                                              _asyncio_internal=True)
+            self.stdin = streams.Stream(mode=streams.StreamMode.WRITE,
+                                        transport=stdin_transport,
+                                        protocol=self,
+                                        loop=self._loop,
+                                        _asyncio_internal=True)
 
     def pipe_data_received(self, fd, data):
         if fd == 1:
@@ -114,6 +121,10 @@ class SubprocessStreamProtocol(streams.FlowControlMixin,
     def _get_close_waiter(self, stream):
         if stream is self.stdin:
             return self._stdin_closed
+        elif stream is self.stdout:
+            return self._stdout_closed
+        elif stream is self.stderr:
+            return self._stderr_closed
 
 
 class Process:

Lib/asyncio/windows_events.py

@@ -607,7 +607,7 @@ class IocpProactor:
 
             # ConnectPipe() failed with ERROR_PIPE_BUSY: retry later
             delay = min(delay * 2, CONNECT_PIPE_MAX_DELAY)
-            await tasks.sleep(delay, loop=self._loop)
+            await tasks.sleep(delay)
 
         return windows_utils.PipeHandle(handle)