bpo-34616: Add PyCF_ALLOW_TOP_LEVEL_AWAIT to allow top-level await (G… · python/cpython@565b4f1 · GitHub
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CarreauYury Selivanov
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bpo-34616: Add PyCF_ALLOW_TOP_LEVEL_AWAIT to allow top-level await (GH-13148)
Co-Authored-By: Yury Selivanov <yury@magic.io>
1 parent aa32a7e commit 565b4f1

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Lines changed: 109 additions & 8 deletions

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‎Doc/library/functions.rst‎

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‎Include/compile.h‎

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@@ -23,6 +23,7 @@ PyAPI_FUNC(PyCodeObject *) PyNode_Compile(struct _node *, const char *);
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#define PyCF_ONLY_AST 0x0400
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#define PyCF_IGNORE_COOKIE 0x0800
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#define PyCF_TYPE_COMMENTS 0x1000
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#define PyCF_ALLOW_TOP_LEVEL_AWAIT 0x2000
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#ifndef Py_LIMITED_API
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typedef struct {

‎Lib/test/test_builtin.py‎

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@@ -1,6 +1,7 @@
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# Python test set -- built-in functions
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import ast
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import asyncio
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import builtins
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import collections
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import decimal
@@ -18,9 +19,14 @@
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import unittest
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import warnings
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from contextlib import ExitStack
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from inspect import CO_COROUTINE
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from itertools import product
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from textwrap import dedent
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from types import AsyncGeneratorType, FunctionType
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from operator import neg
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from test.support import (
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EnvironmentVarGuard, TESTFN, check_warnings, swap_attr, unlink)
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EnvironmentVarGuard, TESTFN, check_warnings, swap_attr, unlink,
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maybe_get_event_loop_policy)
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from test.support.script_helper import assert_python_ok
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from unittest.mock import MagicMock, patch
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try:
@@ -358,6 +364,71 @@ def f(): """doc"""
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rv = ns['f']()
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self.assertEqual(rv, tuple(expected))
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def test_compile_top_level_await(self):
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"""Test whether code some top level await can be compiled.
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Make sure it compiles only with the PyCF_ALLOW_TOP_LEVEL_AWAIT flag set,
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and make sure the generated code object has the CO_COROUTINE flag set in
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order to execute it with `await eval(.....)` instead of exec, or via a
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FunctionType.
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"""
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# helper function just to check we can run top=level async-for
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async def arange(n):
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for i in range(n):
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yield i
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modes = ('single', 'exec')
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code_samples = ['''a = await asyncio.sleep(0, result=1)''',
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'''async for i in arange(1):
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a = 1''',
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'''async with asyncio.Lock() as l:
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a = 1''']
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policy = maybe_get_event_loop_policy()
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try:
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for mode, code_sample in product(modes,code_samples):
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source = dedent(code_sample)
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with self.assertRaises(SyntaxError, msg=f"{source=} {mode=}"):
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compile(source, '?' , mode)
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co = compile(source,
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'?',
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mode,
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flags=ast.PyCF_ALLOW_TOP_LEVEL_AWAIT)
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self.assertEqual(co.co_flags & CO_COROUTINE, CO_COROUTINE,
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msg=f"{source=} {mode=}")
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# test we can create and advance a function type
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globals_ = {'asyncio': asyncio, 'a':0, 'arange': arange}
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async_f = FunctionType(co, globals_)
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asyncio.run(async_f())
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self.assertEqual(globals_['a'], 1)
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# test we can await-eval,
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globals_ = {'asyncio': asyncio, 'a':0, 'arange': arange}
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asyncio.run(eval(co, globals_))
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self.assertEqual(globals_['a'], 1)
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finally:
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asyncio.set_event_loop_policy(policy)
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def test_compile_async_generator(self):
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"""
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With the PyCF_ALLOW_TOP_LEVEL_AWAIT flag added in 3.8, we want to
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make sure AsyncGenerators are still properly not marked with CO_COROUTINE
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"""
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code = dedent("""async def ticker():
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for i in range(10):
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yield i
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await asyncio.sleep(0)""")
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co = compile(code, '?', 'exec', flags=ast.PyCF_ALLOW_TOP_LEVEL_AWAIT)
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glob = {}
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exec(co, glob)
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self.assertEqual(type(glob['ticker']()), AsyncGeneratorType)
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def test_delattr(self):
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sys.spam = 1
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delattr(sys, 'spam')

‎Misc/NEWS.d/next/Core and Builtins/2019-05-07-17-12-37.bpo-34616.0Y0_9r.rst‎

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The ``compile()`` builtin functions now support the ``ast.PyCF_ALLOW_TOP_LEVEL_AWAIT`` flag, which allow to compile sources that contains top-level ``await``, ``async with`` or ``async for``. This is useful to evaluate async-code from with an already async functions; for example in a custom REPL.

‎Parser/asdl_c.py‎

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@@ -1000,6 +1000,8 @@ def visitModule(self, mod):
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self.emit("if (!m) return NULL;", 1)
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self.emit("d = PyModule_GetDict(m);", 1)
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self.emit('if (PyDict_SetItemString(d, "AST", (PyObject*)&AST_type) < 0) return NULL;', 1)
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self.emit('if (PyModule_AddIntMacro(m, PyCF_ALLOW_TOP_LEVEL_AWAIT) < 0)', 1)
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self.emit("return NULL;", 2)
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self.emit('if (PyModule_AddIntMacro(m, PyCF_ONLY_AST) < 0)', 1)
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self.emit("return NULL;", 2)
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self.emit('if (PyModule_AddIntMacro(m, PyCF_TYPE_COMMENTS) < 0)', 1)

‎Python/Python-ast.c‎

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‎Python/compile.c‎

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