Issue #24400: Introduce a distinct type for 'async def' coroutines.
Summary of changes:
1. Coroutines now have a distinct, separate from generators
type at the C level: PyGen_Type, and a new typedef PyCoroObject.
PyCoroObject shares the initial segment of struct layout with
PyGenObject, making it possible to reuse existing generators
machinery. The new type is exposed as 'types.CoroutineType'.
As a consequence of having a new type, CO_GENERATOR flag is
no longer applied to coroutines.
2. Having a separate type for coroutines made it possible to add
an __await__ method to the type. Although it is not used by the
interpreter (see details on that below), it makes coroutines
naturally (without using __instancecheck__) conform to
collections.abc.Coroutine and collections.abc.Awaitable ABCs.
[The __instancecheck__ is still used for generator-based
coroutines, as we don't want to add __await__ for generators.]
3. Add new opcode: GET_YIELD_FROM_ITER. The opcode is needed to
allow passing native coroutines to the YIELD_FROM opcode.
Before this change, 'yield from o' expression was compiled to:
(o)
GET_ITER
LOAD_CONST
YIELD_FROM
Now, we use GET_YIELD_FROM_ITER instead of GET_ITER.
The reason for adding a new opcode is that GET_ITER is used
in some contexts (such as 'for .. in' loops) where passing
a coroutine object is invalid.
4. Add two new introspection functions to the inspec module:
getcoroutinestate(c) and getcoroutinelocals(c).
5. inspect.iscoroutine(o) is updated to test if 'o' is a native
coroutine object. Before this commit it used abc.Coroutine,
and it was requested to update inspect.isgenerator(o) to use
abc.Generator; it was decided, however, that inspect functions
should really be tailored for checking for native types.
6. sys.set_coroutine_wrapper(w) API is updated to work with only
native coroutines. Since types.coroutine decorator supports
any type of callables now, it would be confusing that it does
not work for all types of coroutines.
7. Exceptions logic in generators C implementation was updated
to raise clearer messages for coroutines:
Before: TypeError("generator raised StopIteration")
After: TypeError("coroutine raised StopIteration")
diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py
index e3a3304..8d2b1a3 100644
--- a/Lib/test/test_coroutines.py
+++ b/Lib/test/test_coroutines.py
@@ -24,7 +24,7 @@
def run_async(coro):
- assert coro.__class__ is types.GeneratorType
+ assert coro.__class__ in {types.GeneratorType, types.CoroutineType}
buffer = []
result = None
@@ -37,6 +37,25 @@
return buffer, result
+def run_async__await__(coro):
+ assert coro.__class__ is types.CoroutineType
+ aw = coro.__await__()
+ buffer = []
+ result = None
+ i = 0
+ while True:
+ try:
+ if i % 2:
+ buffer.append(next(aw))
+ else:
+ buffer.append(aw.send(None))
+ i += 1
+ except StopIteration as ex:
+ result = ex.args[0] if ex.args else None
+ break
+ return buffer, result
+
+
@contextlib.contextmanager
def silence_coro_gc():
with warnings.catch_warnings():
@@ -121,22 +140,24 @@
return 10
f = foo()
- self.assertIsInstance(f, types.GeneratorType)
- self.assertTrue(bool(foo.__code__.co_flags & 0x80))
- self.assertTrue(bool(foo.__code__.co_flags & 0x20))
- self.assertTrue(bool(f.gi_code.co_flags & 0x80))
- self.assertTrue(bool(f.gi_code.co_flags & 0x20))
+ self.assertIsInstance(f, types.CoroutineType)
+ self.assertTrue(bool(foo.__code__.co_flags & inspect.CO_COROUTINE))
+ self.assertFalse(bool(foo.__code__.co_flags & inspect.CO_GENERATOR))
+ self.assertTrue(bool(f.cr_code.co_flags & inspect.CO_COROUTINE))
+ self.assertFalse(bool(f.cr_code.co_flags & inspect.CO_GENERATOR))
self.assertEqual(run_async(f), ([], 10))
+ self.assertEqual(run_async__await__(foo()), ([], 10))
+
def bar(): pass
- self.assertFalse(bool(bar.__code__.co_flags & 0x80))
+ self.assertFalse(bool(bar.__code__.co_flags & inspect.CO_COROUTINE))
def test_func_2(self):
async def foo():
raise StopIteration
with self.assertRaisesRegex(
- RuntimeError, "generator raised StopIteration"):
+ RuntimeError, "coroutine raised StopIteration"):
run_async(foo())
@@ -152,7 +173,7 @@
raise StopIteration
check = lambda: self.assertRaisesRegex(
- TypeError, "coroutine-objects do not support iteration")
+ TypeError, "'coroutine' object is not iterable")
with check():
list(foo())
@@ -166,9 +187,6 @@
with check():
iter(foo())
- with check():
- next(foo())
-
with silence_coro_gc(), check():
for i in foo():
pass
@@ -185,7 +203,7 @@
await bar()
check = lambda: self.assertRaisesRegex(
- TypeError, "coroutine-objects do not support iteration")
+ TypeError, "'coroutine' object is not iterable")
with check():
for el in foo(): pass
@@ -221,7 +239,7 @@
with silence_coro_gc(), self.assertRaisesRegex(
TypeError,
- "cannot 'yield from' a coroutine object from a generator"):
+ "cannot 'yield from' a coroutine object in a non-coroutine generator"):
list(foo())
@@ -244,6 +262,98 @@
foo()
support.gc_collect()
+ def test_func_10(self):
+ N = 0
+
+ @types.coroutine
+ def gen():
+ nonlocal N
+ try:
+ a = yield
+ yield (a ** 2)
+ except ZeroDivisionError:
+ N += 100
+ raise
+ finally:
+ N += 1
+
+ async def foo():
+ await gen()
+
+ coro = foo()
+ aw = coro.__await__()
+ self.assertIs(aw, iter(aw))
+ next(aw)
+ self.assertEqual(aw.send(10), 100)
+
+ self.assertEqual(N, 0)
+ aw.close()
+ self.assertEqual(N, 1)
+
+ coro = foo()
+ aw = coro.__await__()
+ next(aw)
+ with self.assertRaises(ZeroDivisionError):
+ aw.throw(ZeroDivisionError, None, None)
+ self.assertEqual(N, 102)
+
+ def test_func_11(self):
+ async def func(): pass
+ coro = func()
+ # Test that PyCoro_Type and _PyCoroWrapper_Type types were properly
+ # initialized
+ self.assertIn('__await__', dir(coro))
+ self.assertIn('__iter__', dir(coro.__await__()))
+ self.assertIn('coroutine_wrapper', repr(coro.__await__()))
+ coro.close() # avoid RuntimeWarning
+
+ def test_func_12(self):
+ async def g():
+ i = me.send(None)
+ await foo
+ me = g()
+ with self.assertRaisesRegex(ValueError,
+ "coroutine already executing"):
+ me.send(None)
+
+ def test_func_13(self):
+ async def g():
+ pass
+ with self.assertRaisesRegex(
+ TypeError,
+ "can't send non-None value to a just-started coroutine"):
+
+ g().send('spam')
+
+ def test_func_14(self):
+ @types.coroutine
+ def gen():
+ yield
+ async def coro():
+ try:
+ await gen()
+ except GeneratorExit:
+ await gen()
+ c = coro()
+ c.send(None)
+ with self.assertRaisesRegex(RuntimeError,
+ "coroutine ignored GeneratorExit"):
+ c.close()
+
+ def test_corotype_1(self):
+ ct = types.CoroutineType
+ self.assertIn('into coroutine', ct.send.__doc__)
+ self.assertIn('inside coroutine', ct.close.__doc__)
+ self.assertIn('in coroutine', ct.throw.__doc__)
+ self.assertIn('of the coroutine', ct.__dict__['__name__'].__doc__)
+ self.assertIn('of the coroutine', ct.__dict__['__qualname__'].__doc__)
+ self.assertEqual(ct.__name__, 'coroutine')
+
+ async def f(): pass
+ c = f()
+ self.assertIn('coroutine object', repr(c))
+ c.close()
+
def test_await_1(self):
async def foo():
@@ -262,6 +372,7 @@
await AsyncYieldFrom([1, 2, 3])
self.assertEqual(run_async(foo()), ([1, 2, 3], None))
+ self.assertEqual(run_async__await__(foo()), ([1, 2, 3], None))
def test_await_4(self):
async def bar():
@@ -1015,6 +1126,27 @@
finally:
sys.set_coroutine_wrapper(None)
+ def test_set_wrapper_4(self):
+ @types.coroutine
+ def foo():
+ return 'spam'
+
+ wrapped = None
+ def wrap(gen):
+ nonlocal wrapped
+ wrapped = gen
+ return gen
+
+ sys.set_coroutine_wrapper(wrap)
+ try:
+ foo()
+ self.assertIs(
+ wrapped, None,
+ "generator-based coroutine was wrapped via "
+ "sys.set_coroutine_wrapper")
+ finally:
+ sys.set_coroutine_wrapper(None)
+
class CAPITest(unittest.TestCase):