[3.12] GH-117894: prevent aclose()/athrow() being re-used after StopIteration (GH-117851) (GH-118226)

(cherry picked from commit 7d369d471c)

Lib/test/test_asyncgen.py

@@ -395,7 +395,11 @@ class AsyncGenTest(unittest.TestCase):
             yield 123
 
         with self.assertWarns(DeprecationWarning):
-            gen().athrow(GeneratorExit, GeneratorExit(), None)
+            x = gen().athrow(GeneratorExit, GeneratorExit(), None)
+        with self.assertRaises(GeneratorExit):
+            x.send(None)
+            del x
+            gc_collect()
 
     def test_async_gen_api_01(self):
         async def gen():
@@ -1653,6 +1657,62 @@ class AsyncGenAsyncioTest(unittest.TestCase):
 
         self.loop.run_until_complete(run())
 
+    def test_async_gen_throw_same_aclose_coro_twice(self):
+        async def async_iterate():
+            yield 1
+            yield 2
+
+        it = async_iterate()
+        nxt = it.aclose()
+        with self.assertRaises(StopIteration):
+            nxt.throw(GeneratorExit)
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            r"cannot reuse already awaited aclose\(\)/athrow\(\)"
+        ):
+            nxt.throw(GeneratorExit)
+
+    def test_async_gen_throw_custom_same_aclose_coro_twice(self):
+        async def async_iterate():
+            yield 1
+            yield 2
+
+        it = async_iterate()
+
+        class MyException(Exception):
+            pass
+
+        nxt = it.aclose()
+        with self.assertRaises(MyException):
+            nxt.throw(MyException)
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            r"cannot reuse already awaited aclose\(\)/athrow\(\)"
+        ):
+            nxt.throw(MyException)
+
+    def test_async_gen_throw_custom_same_athrow_coro_twice(self):
+        async def async_iterate():
+            yield 1
+            yield 2
+
+        it = async_iterate()
+
+        class MyException(Exception):
+            pass
+
+        nxt = it.athrow(MyException)
+        with self.assertRaises(MyException):
+            nxt.throw(MyException)
+
+        with self.assertRaisesRegex(
+            RuntimeError,
+            r"cannot reuse already awaited aclose\(\)/athrow\(\)"
+        ):
+            nxt.throw(MyException)
+
     def test_async_gen_aclose_twice_with_different_coros(self):
         # Regression test for https://bugs.python.org/issue39606
         async def async_iterate():