From 67c35204af609f9663ddf57b97d41e5f29bb009a Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Wed, 13 Dec 2017 21:54:38 +0200
Subject: [PATCH 01/14] Add helpers

---
 Lib/asyncio/events.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py
index e425b06e42fa36..d7e8ff2e46349d 100644
--- a/Lib/asyncio/events.py
+++ b/Lib/asyncio/events.py
@@ -736,3 +736,23 @@ def set_child_watcher(watcher):
     """Equivalent to calling
     get_event_loop_policy().set_child_watcher(watcher)."""
     return get_event_loop_policy().set_child_watcher(watcher)
+
+
+#  shortcuts
+
+def create_task(coro):
+    """Schedule the execution of a coroutine object in a spawn task.
+
+    Return a Task object.
+    """
+    loop = get_running_loop()
+    return loop.create_task(coro)
+
+
+def run_in_executor(executor, func, *args):
+    """Arrange for a func to be called in thread/process pool.
+
+    This function is a coroutine: it returns a future instance.
+    """
+    loop = get_running_loop()
+    return loop.run_in_executor(executor, func, *args)

From d940cc3c2998f9543465bcdf0a88c297a65cc790 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Wed, 13 Dec 2017 22:30:26 +0200
Subject: [PATCH 02/14] Drop run_in_executor shortcut

---
 Lib/asyncio/events.py | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py
index 778ecc6e618ce0..9a32dc1c4a859f 100644
--- a/Lib/asyncio/events.py
+++ b/Lib/asyncio/events.py
@@ -774,12 +774,3 @@ def create_task(coro):
     """
     loop = get_running_loop()
     return loop.create_task(coro)
-
-
-def run_in_executor(executor, func, *args):
-    """Arrange for a func to be called in thread/process pool.
-
-    This function is a coroutine: it returns a future instance.
-    """
-    loop = get_running_loop()
-    return loop.run_in_executor(executor, func, *args)

From 298d38e5b7561d702af9c748813691a8a43154c2 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Wed, 13 Dec 2017 22:54:45 +0200
Subject: [PATCH 03/14] Move create_task() into tasks.py

---
 Lib/asyncio/events.py | 11 -----------
 Lib/asyncio/tasks.py  | 11 ++++++++++-
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py
index 9a32dc1c4a859f..a00f861a9e57b9 100644
--- a/Lib/asyncio/events.py
+++ b/Lib/asyncio/events.py
@@ -763,14 +763,3 @@ def set_child_watcher(watcher):
     _c__set_running_loop = _set_running_loop
     _c_get_running_loop = get_running_loop
     _c_get_event_loop = get_event_loop
-
-
-#  shortcuts
-
-def create_task(coro):
-    """Schedule the execution of a coroutine object in a spawn task.
-
-    Return a Task object.
-    """
-    loop = get_running_loop()
-    return loop.create_task(coro)
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index c5122f760715ac..35350843309b4d 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -1,7 +1,7 @@
 """Support for tasks, coroutines and the scheduler."""
 
 __all__ = (
-    'Task',
+    'Task', 'create_task',
     'FIRST_COMPLETED', 'FIRST_EXCEPTION', 'ALL_COMPLETED',
     'wait', 'wait_for', 'as_completed', 'sleep',
     'gather', 'shield', 'ensure_future', 'run_coroutine_threadsafe',
@@ -263,6 +263,15 @@ def _wakeup(self, future):
     Task = _CTask = _asyncio.Task
 
 
+def create_task(coro):
+    """Schedule the execution of a coroutine object in a spawn task.
+
+    Return a Task object.
+    """
+    loop = get_running_loop()
+    return loop.create_task(coro)
+
+
 # wait() and as_completed() similar to those in PEP 3148.
 
 FIRST_COMPLETED = concurrent.futures.FIRST_COMPLETED

From 8ca254e08a7890557a3fad4e9ec515f12248d60c Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 11:51:52 +0200
Subject: [PATCH 04/14] Extract asyncio.utils, add runtime checks to task ctors

---
 Lib/asyncio/__init__.py        |  4 +-
 Lib/asyncio/base_futures.py    |  4 +-
 Lib/asyncio/constants.py       |  2 +-
 Lib/asyncio/coroutines.py      | 10 ++---
 Lib/asyncio/events.py          | 81 +++-------------------------------
 Lib/asyncio/futures.py         |  3 +-
 Lib/asyncio/tasks.py           |  3 +-
 Lib/asyncio/utils.py           | 78 ++++++++++++++++++++++++++++++++
 Lib/test/test_asyncio/utils.py |  3 +-
 Modules/_asynciomodule.c       | 23 ++++++++++
 10 files changed, 123 insertions(+), 88 deletions(-)
 create mode 100644 Lib/asyncio/utils.py

diff --git a/Lib/asyncio/__init__.py b/Lib/asyncio/__init__.py
index dd6686de84056a..cda091235f21fa 100644
--- a/Lib/asyncio/__init__.py
+++ b/Lib/asyncio/__init__.py
@@ -16,6 +16,7 @@
 from .subprocess import *
 from .tasks import *
 from .transports import *
+from .utils import *
 
 __all__ = (base_events.__all__ +
            coroutines.__all__ +
@@ -27,7 +28,8 @@
            streams.__all__ +
            subprocess.__all__ +
            tasks.__all__ +
-           transports.__all__)
+           transports.__all__ +
+           utils.__all__)
 
 if sys.platform == 'win32':  # pragma: no cover
     from .windows_events import *
diff --git a/Lib/asyncio/base_futures.py b/Lib/asyncio/base_futures.py
index 2ee82c3f057033..9b3789eb230af0 100644
--- a/Lib/asyncio/base_futures.py
+++ b/Lib/asyncio/base_futures.py
@@ -3,7 +3,7 @@
 import concurrent.futures._base
 import reprlib
 
-from . import events
+from . import utils
 
 Error = concurrent.futures._base.Error
 CancelledError = concurrent.futures.CancelledError
@@ -38,7 +38,7 @@ def _format_callbacks(cb):
         cb = ''
 
     def format_cb(callback):
-        return events._format_callback_source(callback, ())
+        return utils._format_callback_source(callback, ())
 
     if size == 1:
         cb = format_cb(cb[0])
diff --git a/Lib/asyncio/constants.py b/Lib/asyncio/constants.py
index dfe97f4985969f..823cef70695150 100644
--- a/Lib/asyncio/constants.py
+++ b/Lib/asyncio/constants.py
@@ -6,5 +6,5 @@
 
 # Number of stack entries to capture in debug mode.
 # The larger the number, the slower the operation in debug mode
-# (see extract_stack() in events.py).
+# (see extract_stack() in utils.py).
 DEBUG_STACK_DEPTH = 10
diff --git a/Lib/asyncio/coroutines.py b/Lib/asyncio/coroutines.py
index bca7fe3a53742d..6d86406bd3c192 100644
--- a/Lib/asyncio/coroutines.py
+++ b/Lib/asyncio/coroutines.py
@@ -9,9 +9,9 @@
 
 from collections.abc import Awaitable, Coroutine
 
-from . import constants
-from . import events
 from . import base_futures
+from . import constants
+from . import utils
 from .log import logger
 
 
@@ -48,7 +48,7 @@ def __init__(self, gen, func=None):
         assert inspect.isgenerator(gen) or inspect.iscoroutine(gen), gen
         self.gen = gen
         self.func = func  # Used to unwrap @coroutine decorator
-        self._source_traceback = events.extract_stack(sys._getframe(1))
+        self._source_traceback = utils.extract_stack(sys._getframe(1))
         self.__name__ = getattr(gen, '__name__', None)
         self.__qualname__ = getattr(gen, '__qualname__', None)
 
@@ -243,7 +243,7 @@ def _format_coroutine(coro):
         func = coro
 
     if coro_name is None:
-        coro_name = events._format_callback(func, (), {})
+        coro_name = utils._format_callback(func, (), {})
 
     try:
         coro_code = coro.gi_code
@@ -260,7 +260,7 @@ def _format_coroutine(coro):
     if (isinstance(coro, CoroWrapper) and
             not inspect.isgeneratorfunction(coro.func) and
             coro.func is not None):
-        source = events._get_function_source(coro.func)
+        source = utils._get_function_source(coro.func)
         if source is not None:
             filename, lineno = source
         if coro_frame is None:
diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py
index a00f861a9e57b9..b43eff2bcd9a81 100644
--- a/Lib/asyncio/events.py
+++ b/Lib/asyncio/events.py
@@ -11,86 +11,14 @@
     '_get_running_loop',
 )
 
-import functools
-import inspect
 import os
-import reprlib
 import socket
 import subprocess
 import sys
 import threading
-import traceback
 
 from . import constants
-
-
-def _get_function_source(func):
-    func = inspect.unwrap(func)
-    if inspect.isfunction(func):
-        code = func.__code__
-        return (code.co_filename, code.co_firstlineno)
-    if isinstance(func, functools.partial):
-        return _get_function_source(func.func)
-    if isinstance(func, functools.partialmethod):
-        return _get_function_source(func.func)
-    return None
-
-
-def _format_args_and_kwargs(args, kwargs):
-    """Format function arguments and keyword arguments.
-
-    Special case for a single parameter: ('hello',) is formatted as ('hello').
-    """
-    # use reprlib to limit the length of the output
-    items = []
-    if args:
-        items.extend(reprlib.repr(arg) for arg in args)
-    if kwargs:
-        items.extend(f'{k}={reprlib.repr(v)}' for k, v in kwargs.items())
-    return '({})'.format(', '.join(items))
-
-
-def _format_callback(func, args, kwargs, suffix=''):
-    if isinstance(func, functools.partial):
-        suffix = _format_args_and_kwargs(args, kwargs) + suffix
-        return _format_callback(func.func, func.args, func.keywords, suffix)
-
-    if hasattr(func, '__qualname__'):
-        func_repr = getattr(func, '__qualname__')
-    elif hasattr(func, '__name__'):
-        func_repr = getattr(func, '__name__')
-    else:
-        func_repr = repr(func)
-
-    func_repr += _format_args_and_kwargs(args, kwargs)
-    if suffix:
-        func_repr += suffix
-    return func_repr
-
-
-def _format_callback_source(func, args):
-    func_repr = _format_callback(func, args, None)
-    source = _get_function_source(func)
-    if source:
-        func_repr += f' at {source[0]}:{source[1]}'
-    return func_repr
-
-
-def extract_stack(f=None, limit=None):
-    """Replacement for traceback.extract_stack() that only does the
-    necessary work for asyncio debug mode.
-    """
-    if f is None:
-        f = sys._getframe().f_back
-    if limit is None:
-        # Limit the amount of work to a reasonable amount, as extract_stack()
-        # can be called for each coroutine and future in debug mode.
-        limit = constants.DEBUG_STACK_DEPTH
-    stack = traceback.StackSummary.extract(traceback.walk_stack(f),
-                                           limit=limit,
-                                           lookup_lines=False)
-    stack.reverse()
-    return stack
+from . import utils
 
 
 class Handle:
@@ -106,7 +34,7 @@ def __init__(self, callback, args, loop):
         self._cancelled = False
         self._repr = None
         if self._loop.get_debug():
-            self._source_traceback = extract_stack(sys._getframe(1))
+            self._source_traceback = utils.extract_stack(sys._getframe(1))
         else:
             self._source_traceback = None
 
@@ -115,7 +43,8 @@ def _repr_info(self):
         if self._cancelled:
             info.append('cancelled')
         if self._callback is not None:
-            info.append(_format_callback_source(self._callback, self._args))
+            info.append(utils._format_callback_source(self._callback,
+                                                      self._args))
         if self._source_traceback:
             frame = self._source_traceback[-1]
             info.append(f'created at {frame[0]}:{frame[1]}')
@@ -145,7 +74,7 @@ def _run(self):
         try:
             self._callback(*self._args)
         except Exception as exc:
-            cb = _format_callback_source(self._callback, self._args)
+            cb = utils._format_callback_source(self._callback, self._args)
             msg = f'Exception in callback {cb}'
             context = {
                 'message': msg,
diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
index d46a295197b876..2523c60e85755b 100644
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -11,6 +11,7 @@
 
 from . import base_futures
 from . import events
+from . import utils
 
 
 CancelledError = base_futures.CancelledError
@@ -79,7 +80,7 @@ def __init__(self, *, loop=None):
             self._loop = loop
         self._callbacks = []
         if self._loop.get_debug():
-            self._source_traceback = events.extract_stack(sys._getframe(1))
+            self._source_traceback = utils.extract_stack(sys._getframe(1))
 
     _repr_info = base_futures._future_repr_info
 
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 35350843309b4d..5ea564b05999ac 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -67,7 +67,8 @@ def all_tasks(cls, loop=None):
         return {t for t in cls._all_tasks if t._loop is loop}
 
     def __init__(self, coro, *, loop=None):
-        assert coroutines.iscoroutine(coro), repr(coro)
+        if not coroutines.iscoroutine(coro):
+            raise TypeError(f"{coro!r} is not a coroutine")
         super().__init__(loop=loop)
         if self._source_traceback:
             del self._source_traceback[-1]
diff --git a/Lib/asyncio/utils.py b/Lib/asyncio/utils.py
new file mode 100644
index 00000000000000..78447c51f68d24
--- /dev/null
+++ b/Lib/asyncio/utils.py
@@ -0,0 +1,78 @@
+import functools
+import inspect
+import reprlib
+import traceback
+
+from . import constants
+
+
+__all__ = ('extract_stack',)
+
+
+def _get_function_source(func):
+    func = inspect.unwrap(func)
+    if inspect.isfunction(func):
+        code = func.__code__
+        return (code.co_filename, code.co_firstlineno)
+    if isinstance(func, functools.partial):
+        return _get_function_source(func.func)
+    if isinstance(func, functools.partialmethod):
+        return _get_function_source(func.func)
+    return None
+
+
+def _format_callback_source(func, args):
+    func_repr = _format_callback(func, args, None)
+    source = _get_function_source(func)
+    if source:
+        func_repr += f' at {source[0]}:{source[1]}'
+    return func_repr
+
+
+def _format_args_and_kwargs(args, kwargs):
+    """Format function arguments and keyword arguments.
+
+    Special case for a single parameter: ('hello',) is formatted as ('hello').
+    """
+    # use reprlib to limit the length of the output
+    items = []
+    if args:
+        items.extend(reprlib.repr(arg) for arg in args)
+    if kwargs:
+        items.extend(f'{k}={reprlib.repr(v)}' for k, v in kwargs.items())
+    return '({})'.format(', '.join(items))
+
+
+def _format_callback(func, args, kwargs, suffix=''):
+    if isinstance(func, functools.partial):
+        suffix = _format_args_and_kwargs(args, kwargs) + suffix
+        return _format_callback(func.func, func.args, func.keywords, suffix)
+
+    if hasattr(func, '__qualname__'):
+        func_repr = getattr(func, '__qualname__')
+    elif hasattr(func, '__name__'):
+        func_repr = getattr(func, '__name__')
+    else:
+        func_repr = repr(func)
+
+    func_repr += _format_args_and_kwargs(args, kwargs)
+    if suffix:
+        func_repr += suffix
+    return func_repr
+
+
+def extract_stack(f=None, limit=None):
+    """Replacement for traceback.extract_stack() that only does the
+    necessary work for asyncio debug mode.
+    """
+    if f is None:
+        f = sys._getframe().f_back
+    if limit is None:
+        # Limit the amount of work to a reasonable amount, as extract_stack()
+        # can be called for each coroutine and future in debug mode.
+        limit = constants.DEBUG_STACK_DEPTH
+    stack = traceback.StackSummary.extract(traceback.walk_stack(f),
+                                           limit=limit,
+                                           lookup_lines=False)
+    stack.reverse()
+    return stack
diff --git a/Lib/test/test_asyncio/utils.py b/Lib/test/test_asyncio/utils.py
index 560db9f562d82f..0e1adcc5fba8ba 100644
--- a/Lib/test/test_asyncio/utils.py
+++ b/Lib/test/test_asyncio/utils.py
@@ -30,6 +30,7 @@
 from asyncio import events
 from asyncio import futures
 from asyncio import tasks
+from asyncio import utils
 from asyncio.log import logger
 from test import support
 
@@ -429,7 +430,7 @@ def __eq__(self, other):
 
 
 def get_function_source(func):
-    source = events._get_function_source(func)
+    source = utils._get_function_source(func)
     if source is None:
         raise ValueError("unable to get the source of %r" % (func,))
     return source
diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index 01c38b80b95f8f..6bc58e873fa503 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -26,6 +26,7 @@ static PyObject *all_tasks;
 static PyObject *current_tasks;
 static PyObject *traceback_extract_stack;
 static PyObject *asyncio_get_event_loop_policy;
+static PyObject *asyncio_iscoroutine_func;
 static PyObject *asyncio_future_repr_info_func;
 static PyObject *asyncio_task_repr_info_func;
 static PyObject *asyncio_task_get_stack_func;
@@ -1461,8 +1462,26 @@ _asyncio_Task___init___impl(TaskObj *self, PyObject *coro, PyObject *loop)
 /*[clinic end generated code: output=9f24774c2287fc2f input=8d132974b049593e]*/
 {
     PyObject *res;
+    int tmp;
     _Py_IDENTIFIER(add);
 
+    if (!PyCoro_CheckExact(coro)) {
+        // fastpath failed, perfom slow check
+        res = PyObject_CallFunctionObjArgs(asyncio_iscoroutine_func,
+                                           coro, NULL);
+        if (res == NULL) {
+            return -1;
+        }
+        tmp = PyObject_Not(res);
+        Py_DECREF(res);
+        if (tmp < 0) {
+            return -1;
+        }
+        if (tmp) {
+            PyErr_Format(PyExc_TypeError, "%R is not a coroutine", coro, NULL);
+            return -1;
+        }
+    }
     if (future_init((FutureObj*)self, loop)) {
         return -1;
     }
@@ -2604,6 +2623,7 @@ module_free(void *m)
     Py_CLEAR(traceback_extract_stack);
     Py_CLEAR(asyncio_get_event_loop_policy);
     Py_CLEAR(asyncio_future_repr_info_func);
+    Py_CLEAR(asyncio_iscoroutine_func);
     Py_CLEAR(asyncio_task_repr_info_func);
     Py_CLEAR(asyncio_task_get_stack_func);
     Py_CLEAR(asyncio_task_print_stack_func);
@@ -2645,6 +2665,9 @@ module_init(void)
     GET_MOD_ATTR(asyncio_task_get_stack_func, "_task_get_stack")
     GET_MOD_ATTR(asyncio_task_print_stack_func, "_task_print_stack")
 
+    WITH_MOD("asyncio.coroutines")
+    GET_MOD_ATTR(asyncio_iscoroutine_func, "iscoroutine")
+
     WITH_MOD("inspect")
     GET_MOD_ATTR(inspect_isgenerator, "isgenerator")
 

From a25f1cba0c7af0d7f913cbce6bac4257b35fbb1a Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 12:21:45 +0200
Subject: [PATCH 05/14] Add tests

---
 Lib/asyncio/tasks.py                | 13 +++++++++----
 Lib/test/test_asyncio/test_tasks.py | 23 +++++++++++++++++++++++
 Modules/_asynciomodule.c            | 10 ++++++----
 3 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 5ea564b05999ac..35cfae2500e483 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -67,14 +67,19 @@ def all_tasks(cls, loop=None):
         return {t for t in cls._all_tasks if t._loop is loop}
 
     def __init__(self, coro, *, loop=None):
-        if not coroutines.iscoroutine(coro):
-            raise TypeError(f"{coro!r} is not a coroutine")
         super().__init__(loop=loop)
         if self._source_traceback:
             del self._source_traceback[-1]
-        self._coro = coro
-        self._fut_waiter = None
+        if not coroutines.iscoroutine(coro):
+            # raise after Future.__init__(), attrs are required for __del__
+            # prevent logging for pending task in __del__
+            self._log_destroy_pending = False
+            raise TypeError(f"{coro!r} is not a coroutine")
+
         self._must_cancel = False
+        self._fut_waiter = None
+        self._coro = coro
+
         self._loop.call_soon(self._step)
         self.__class__._all_tasks.add(self)
 
diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 0838ebf3a7b4f7..6b529860475aea 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -2054,6 +2054,29 @@ def coro():
 
         self.assertEqual(self.Task.all_tasks(self.loop), set())
 
+    def test_create_task_with_noncoroutine(self):
+        with self.assertRaises(TypeError):
+            self.new_task(self.loop, 123)
+
+    def test_create_task_with_oldstyle_coroutine(self):
+
+        @asyncio.coroutine
+        def coro():
+            pass
+
+        task = self.new_task(self.loop, coro())
+        self.assertIsInstance(task, self.Task)
+        self.loop.run_until_complete(task)
+
+    def test_create_task_with_async_function(self):
+
+        async def coro():
+            pass
+
+        task = self.new_task(self.loop, coro())
+        self.assertIsInstance(task, self.Task)
+        self.loop.run_until_complete(task)
+
 
 def add_subclass_tests(cls):
     BaseTask = cls.Task
diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index 6bc58e873fa503..fd36af8dff5ca8 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -1465,8 +1465,13 @@ _asyncio_Task___init___impl(TaskObj *self, PyObject *coro, PyObject *loop)
     int tmp;
     _Py_IDENTIFIER(add);
 
+    if (future_init((FutureObj*)self, loop)) {
+        return -1;
+    }
+
     if (!PyCoro_CheckExact(coro)) {
         // fastpath failed, perfom slow check
+        // raise after Future.__init__(), attrs are required for __del__
         res = PyObject_CallFunctionObjArgs(asyncio_iscoroutine_func,
                                            coro, NULL);
         if (res == NULL) {
@@ -1478,18 +1483,15 @@ _asyncio_Task___init___impl(TaskObj *self, PyObject *coro, PyObject *loop)
             return -1;
         }
         if (tmp) {
+            self->task_log_destroy_pending = 0;
             PyErr_Format(PyExc_TypeError, "%R is not a coroutine", coro, NULL);
             return -1;
         }
     }
-    if (future_init((FutureObj*)self, loop)) {
-        return -1;
-    }
 
     self->task_fut_waiter = NULL;
     self->task_must_cancel = 0;
     self->task_log_destroy_pending = 1;
-
     Py_INCREF(coro);
     self->task_coro = coro;
 

From ef9ccda913d382ce259cb4a812705ed6d409e879 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 12:27:15 +0200
Subject: [PATCH 06/14] utils.py -> format_helpers.py

---
 Lib/asyncio/__init__.py                     |  6 +++---
 Lib/asyncio/base_futures.py                 |  4 ++--
 Lib/asyncio/coroutines.py                   |  8 ++++----
 Lib/asyncio/events.py                       | 12 +++++++-----
 Lib/asyncio/{utils.py => format_helpers.py} |  0
 Lib/asyncio/futures.py                      |  5 +++--
 Lib/test/test_asyncio/utils.py              |  4 ++--
 7 files changed, 21 insertions(+), 18 deletions(-)
 rename Lib/asyncio/{utils.py => format_helpers.py} (100%)

diff --git a/Lib/asyncio/__init__.py b/Lib/asyncio/__init__.py
index cda091235f21fa..4510e0aa9cfd30 100644
--- a/Lib/asyncio/__init__.py
+++ b/Lib/asyncio/__init__.py
@@ -8,6 +8,7 @@
 from .base_events import *
 from .coroutines import *
 from .events import *
+from .format_helpers import *
 from .futures import *
 from .locks import *
 from .protocols import *
@@ -16,11 +17,11 @@
 from .subprocess import *
 from .tasks import *
 from .transports import *
-from .utils import *
 
 __all__ = (base_events.__all__ +
            coroutines.__all__ +
            events.__all__ +
+           format_helpers.__all__ +
            futures.__all__ +
            locks.__all__ +
            protocols.__all__ +
@@ -28,8 +29,7 @@
            streams.__all__ +
            subprocess.__all__ +
            tasks.__all__ +
-           transports.__all__ +
-           utils.__all__)
+           transports.__all__)
 
 if sys.platform == 'win32':  # pragma: no cover
     from .windows_events import *
diff --git a/Lib/asyncio/base_futures.py b/Lib/asyncio/base_futures.py
index 9b3789eb230af0..008812eda91bbf 100644
--- a/Lib/asyncio/base_futures.py
+++ b/Lib/asyncio/base_futures.py
@@ -3,7 +3,7 @@
 import concurrent.futures._base
 import reprlib
 
-from . import utils
+from . import format_helpers
 
 Error = concurrent.futures._base.Error
 CancelledError = concurrent.futures.CancelledError
@@ -38,7 +38,7 @@ def _format_callbacks(cb):
         cb = ''
 
     def format_cb(callback):
-        return utils._format_callback_source(callback, ())
+        return format_helpers._format_callback_source(callback, ())
 
     if size == 1:
         cb = format_cb(cb[0])
diff --git a/Lib/asyncio/coroutines.py b/Lib/asyncio/coroutines.py
index 6d86406bd3c192..e3c0162dd1458c 100644
--- a/Lib/asyncio/coroutines.py
+++ b/Lib/asyncio/coroutines.py
@@ -11,7 +11,7 @@
 
 from . import base_futures
 from . import constants
-from . import utils
+from . import format_helpers
 from .log import logger
 
 
@@ -48,7 +48,7 @@ def __init__(self, gen, func=None):
         assert inspect.isgenerator(gen) or inspect.iscoroutine(gen), gen
         self.gen = gen
         self.func = func  # Used to unwrap @coroutine decorator
-        self._source_traceback = utils.extract_stack(sys._getframe(1))
+        self._source_traceback = format_helpers.extract_stack(sys._getframe(1))
         self.__name__ = getattr(gen, '__name__', None)
         self.__qualname__ = getattr(gen, '__qualname__', None)
 
@@ -243,7 +243,7 @@ def _format_coroutine(coro):
         func = coro
 
     if coro_name is None:
-        coro_name = utils._format_callback(func, (), {})
+        coro_name = format_helpers._format_callback(func, (), {})
 
     try:
         coro_code = coro.gi_code
@@ -260,7 +260,7 @@ def _format_coroutine(coro):
     if (isinstance(coro, CoroWrapper) and
             not inspect.isgeneratorfunction(coro.func) and
             coro.func is not None):
-        source = utils._get_function_source(coro.func)
+        source = format_helpers._get_function_source(coro.func)
         if source is not None:
             filename, lineno = source
         if coro_frame is None:
diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py
index b43eff2bcd9a81..974a4a22218fd5 100644
--- a/Lib/asyncio/events.py
+++ b/Lib/asyncio/events.py
@@ -18,7 +18,7 @@
 import threading
 
 from . import constants
-from . import utils
+from . import format_helpers
 
 
 class Handle:
@@ -34,7 +34,8 @@ def __init__(self, callback, args, loop):
         self._cancelled = False
         self._repr = None
         if self._loop.get_debug():
-            self._source_traceback = utils.extract_stack(sys._getframe(1))
+            self._source_traceback = format_helpers.extract_stack(
+                sys._getframe(1))
         else:
             self._source_traceback = None
 
@@ -43,8 +44,8 @@ def _repr_info(self):
         if self._cancelled:
             info.append('cancelled')
         if self._callback is not None:
-            info.append(utils._format_callback_source(self._callback,
-                                                      self._args))
+            info.append(format_helpers._format_callback_source(
+                self._callback, self._args))
         if self._source_traceback:
             frame = self._source_traceback[-1]
             info.append(f'created at {frame[0]}:{frame[1]}')
@@ -74,7 +75,8 @@ def _run(self):
         try:
             self._callback(*self._args)
         except Exception as exc:
-            cb = utils._format_callback_source(self._callback, self._args)
+            cb = format_helpers._format_callback_source(
+                self._callback, self._args)
             msg = f'Exception in callback {cb}'
             context = {
                 'message': msg,
diff --git a/Lib/asyncio/utils.py b/Lib/asyncio/format_helpers.py
similarity index 100%
rename from Lib/asyncio/utils.py
rename to Lib/asyncio/format_helpers.py
diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
index 2523c60e85755b..b310962f9fe19d 100644
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -11,7 +11,7 @@
 
 from . import base_futures
 from . import events
-from . import utils
+from . import format_helpers
 
 
 CancelledError = base_futures.CancelledError
@@ -80,7 +80,8 @@ def __init__(self, *, loop=None):
             self._loop = loop
         self._callbacks = []
         if self._loop.get_debug():
-            self._source_traceback = utils.extract_stack(sys._getframe(1))
+            self._source_traceback = format_helpers.extract_stack(
+                sys._getframe(1))
 
     _repr_info = base_futures._future_repr_info
 
diff --git a/Lib/test/test_asyncio/utils.py b/Lib/test/test_asyncio/utils.py
index 0e1adcc5fba8ba..a1a9bb3684c3a9 100644
--- a/Lib/test/test_asyncio/utils.py
+++ b/Lib/test/test_asyncio/utils.py
@@ -28,9 +28,9 @@
 
 from asyncio import base_events
 from asyncio import events
+from asyncio import format_helpers
 from asyncio import futures
 from asyncio import tasks
-from asyncio import utils
 from asyncio.log import logger
 from test import support
 
@@ -430,7 +430,7 @@ def __eq__(self, other):
 
 
 def get_function_source(func):
-    source = utils._get_function_source(func)
+    source = format_helpers._get_function_source(func)
     if source is None:
         raise ValueError("unable to get the source of %r" % (func,))
     return source

From 7cbb758fac7078575529f31211936a77b4e5dad5 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 17:20:21 +0200
Subject: [PATCH 07/14] Don't expose asyncio.extract_stack

---
 Lib/asyncio/__init__.py       | 2 --
 Lib/asyncio/format_helpers.py | 3 ---
 2 files changed, 5 deletions(-)

diff --git a/Lib/asyncio/__init__.py b/Lib/asyncio/__init__.py
index 4510e0aa9cfd30..dd6686de84056a 100644
--- a/Lib/asyncio/__init__.py
+++ b/Lib/asyncio/__init__.py
@@ -8,7 +8,6 @@
 from .base_events import *
 from .coroutines import *
 from .events import *
-from .format_helpers import *
 from .futures import *
 from .locks import *
 from .protocols import *
@@ -21,7 +20,6 @@
 __all__ = (base_events.__all__ +
            coroutines.__all__ +
            events.__all__ +
-           format_helpers.__all__ +
            futures.__all__ +
            locks.__all__ +
            protocols.__all__ +
diff --git a/Lib/asyncio/format_helpers.py b/Lib/asyncio/format_helpers.py
index 78447c51f68d24..39cfcee0c1c8bf 100644
--- a/Lib/asyncio/format_helpers.py
+++ b/Lib/asyncio/format_helpers.py
@@ -6,9 +6,6 @@
 from . import constants
 
 
-__all__ = ('extract_stack',)
-
-
 def _get_function_source(func):
     func = inspect.unwrap(func)
     if inspect.isfunction(func):

From 14b2588ac08586644d0a51920792ad26ed60fa4d Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 17:25:17 +0200
Subject: [PATCH 08/14] Add test for asyncio.create_task()

---
 Lib/test/test_asyncio/test_tasks.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 6b529860475aea..9bd83d6127f488 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -2077,6 +2077,19 @@ async def coro():
         self.assertIsInstance(task, self.Task)
         self.loop.run_until_complete(task)
 
+    def test_bare_create_task(self):
+
+        async def inner():
+            return 1
+
+        async def coro():
+            task = asyncio.create_task(inner())
+            self.assertIsInstance(task, self.Task)
+            ret = await task
+            self.assertEqual(1, ret)
+
+        self.loop.run_until_complete(coro())
+
 
 def add_subclass_tests(cls):
     BaseTask = cls.Task

From e1c1ed1301ec0e43a44248eb647f49a1413dfcee Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 17:26:49 +0200
Subject: [PATCH 09/14] Fix implementation

---
 Lib/asyncio/tasks.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 35cfae2500e483..4fe78e9e0627cf 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -274,7 +274,7 @@ def create_task(coro):
 
     Return a Task object.
     """
-    loop = get_running_loop()
+    loop = events.get_running_loop()
     return loop.create_task(coro)
 
 

From 8533c7404c295efad64c0b80b1c2d5588ae16f30 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 17:29:07 +0200
Subject: [PATCH 10/14] Add NEWS entry

---
 .../NEWS.d/next/Library/2017-12-14-17-28-54.bpo-32311.DL5Ytn.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2017-12-14-17-28-54.bpo-32311.DL5Ytn.rst

diff --git a/Misc/NEWS.d/next/Library/2017-12-14-17-28-54.bpo-32311.DL5Ytn.rst b/Misc/NEWS.d/next/Library/2017-12-14-17-28-54.bpo-32311.DL5Ytn.rst
new file mode 100644
index 00000000000000..e2d10959476cdc
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-12-14-17-28-54.bpo-32311.DL5Ytn.rst
@@ -0,0 +1 @@
+Implement asyncio.create_task(coro) shortcut

From 0f6ca60c2fb58d3b42a12a0e4493492ea3e49aa3 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 17:47:20 +0200
Subject: [PATCH 11/14] Update docs

---
 Doc/library/asyncio-task.rst | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst
index a8a0a8e85efe72..749b4abb51ba4f 100644
--- a/Doc/library/asyncio-task.rst
+++ b/Doc/library/asyncio-task.rst
@@ -358,10 +358,21 @@ with the result.
 Task
 ----
 
+.. function:: create_task(coro)
+
+   Schedule the execution of a :ref:`coroutine <coroutine>` object
+   *coro* in a spawn task.
+
+   The task is executed in :func:`get_running_loop` context,
+   :exc:`RuntimeError` is raised if there is no running loop in
+   current thread.
+
+   .. versionadded:: 3.7
+
 .. class:: Task(coro, \*, loop=None)
 
-   Schedule the execution of a :ref:`coroutine <coroutine>`: wrap it in a
-   future. A task is a subclass of :class:`Future`.
+   A unit for concurrent running of :ref:`coroutines <coroutine>`,
+   subclass of :class:`Future`.
 
    A task is responsible for executing a coroutine object in an event loop.  If
    the wrapped coroutine yields from a future, the task suspends the execution
@@ -386,7 +397,7 @@ Task
    <coroutine>` did not complete. It is probably a bug and a warning is
    logged: see :ref:`Pending task destroyed <asyncio-pending-task-destroyed>`.
 
-   Don't directly create :class:`Task` instances: use the :func:`ensure_future`
+   Don't directly create :class:`Task` instances: use the :func:`create_task`
    function or the :meth:`AbstractEventLoop.create_task` method.
 
    This class is :ref:`not thread safe <asyncio-multithreading>`.
@@ -534,9 +545,15 @@ Task functions
    .. versionchanged:: 3.5.1
       The function accepts any :term:`awaitable` object.
 
+   .. note::
+
+      :func:`create_task` (added in Python 3.7) is the preferable way
+      for spawning new tasks.
+
    .. seealso::
 
-      The :meth:`AbstractEventLoop.create_task` method.
+      The :func:`create_task` function and
+      :meth:`AbstractEventLoop.create_task` method.
 
 .. function:: wrap_future(future, \*, loop=None)
 

From a5d4a8bc05f8da7e25333c5b0b9f89b8abd7e163 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 18:18:33 +0200
Subject: [PATCH 12/14] Change exception message

---
 Lib/asyncio/tasks.py                | 2 +-
 Lib/test/test_asyncio/test_tasks.py | 3 ++-
 Modules/_asynciomodule.c            | 4 +++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 4fe78e9e0627cf..172057e5a29a53 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -74,7 +74,7 @@ def __init__(self, coro, *, loop=None):
             # raise after Future.__init__(), attrs are required for __del__
             # prevent logging for pending task in __del__
             self._log_destroy_pending = False
-            raise TypeError(f"{coro!r} is not a coroutine")
+            raise TypeError(f"a coroutine was expected, got {coro!r}")
 
         self._must_cancel = False
         self._fut_waiter = None
diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 9bd83d6127f488..6e2a16f2a0556b 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -2055,7 +2055,8 @@ def coro():
         self.assertEqual(self.Task.all_tasks(self.loop), set())
 
     def test_create_task_with_noncoroutine(self):
-        with self.assertRaises(TypeError):
+        with self.assertRaisesRegex(TypeError,
+                                    "a coroutine was expected, got 123"):
             self.new_task(self.loop, 123)
 
     def test_create_task_with_oldstyle_coroutine(self):
diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index fd36af8dff5ca8..9ac1c44d48d380 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -1484,7 +1484,9 @@ _asyncio_Task___init___impl(TaskObj *self, PyObject *coro, PyObject *loop)
         }
         if (tmp) {
             self->task_log_destroy_pending = 0;
-            PyErr_Format(PyExc_TypeError, "%R is not a coroutine", coro, NULL);
+            PyErr_Format(PyExc_TypeError,
+                         "a coroutine was expected, got %R",
+                         coro, NULL);
             return -1;
         }
     }

From 06662766b87b724cfa23206d6c7189598a1264b9 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 18:53:09 +0200
Subject: [PATCH 13/14] Update doc

---
 Doc/library/asyncio-task.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst
index 749b4abb51ba4f..243bfd7873603b 100644
--- a/Doc/library/asyncio-task.rst
+++ b/Doc/library/asyncio-task.rst
@@ -360,8 +360,8 @@ Task
 
 .. function:: create_task(coro)
 
-   Schedule the execution of a :ref:`coroutine <coroutine>` object
-   *coro* in a spawn task.
+   Wrap a :ref:`coroutine <coroutine>` *coro* into a task and schedule
+   its execution.
 
    The task is executed in :func:`get_running_loop` context,
    :exc:`RuntimeError` is raised if there is no running loop in

From 5dbae4e32c3eafe3ff1a591a395ea5d9fbbaea09 Mon Sep 17 00:00:00 2001
From: Andrew Svetlov <andrew.svetlov@gmail.com>
Date: Thu, 14 Dec 2017 23:05:57 +0200
Subject: [PATCH 14/14] Fix notes

---
 Doc/library/asyncio-task.rst | 2 +-
 Lib/asyncio/constants.py     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst
index 243bfd7873603b..72458c8cfd62e3 100644
--- a/Doc/library/asyncio-task.rst
+++ b/Doc/library/asyncio-task.rst
@@ -361,7 +361,7 @@ Task
 .. function:: create_task(coro)
 
    Wrap a :ref:`coroutine <coroutine>` *coro* into a task and schedule
-   its execution.
+   its execution.  Return the task object.
 
    The task is executed in :func:`get_running_loop` context,
    :exc:`RuntimeError` is raised if there is no running loop in
diff --git a/Lib/asyncio/constants.py b/Lib/asyncio/constants.py
index 823cef70695150..52169c3f8e5b12 100644
--- a/Lib/asyncio/constants.py
+++ b/Lib/asyncio/constants.py
@@ -6,5 +6,5 @@
 
 # Number of stack entries to capture in debug mode.
 # The larger the number, the slower the operation in debug mode
-# (see extract_stack() in utils.py).
+# (see extract_stack() in format_helpers.py).
 DEBUG_STACK_DEPTH = 10