Python 将可迭代项包含在生成器表达式中会更改上下文的清理顺序

我有一个包含两个嵌套的with个块的Python应用程序，其中一个块发生在对象的__iter__方法中.我观察到，将可迭代对象包装在生成器表达式中会改变引发异常时完成这with个块的顺序，我对此感到非常惊讶.

我使用的是python3.11.5，但在3.8.17中观察到了相同的行为.

这是一个演示，它再现了观察到的行为和预期的行为:

from contextlib import closing, contextmanager


class Reader:
    def close(self):
        print(f"CLOSE: {self.__class__.__name__}")

    @contextmanager
    def get_resource(self):
        try:
            yield 42
        finally:
            print(f"CLOSE: {self.__class__.__name__} releases resource")


class Container:
    def __init__(self, reader: Reader):
        self._reader = reader

    def __iter__(self):
        with self._reader.get_resource() as resource:
            for x in range(10):
                yield x


def my_code():
    with closing(Reader()) as reader:
        container = Container(reader)
        container_gen = (x for x in container)
        for thing in container_gen:
            assert False


def expected():
    with closing(Reader()) as reader:
        container = Container(reader)
        for thing in container:
            assert False


print(">>> What my code does:")
try:
    my_code()
except AssertionError:
    print("handle exception")

print()

print(">>> The context handling I expected:")
try:
    expected()
except AssertionError:
    print("handle exception")

这是我从下面的代码中得到的输出:

>>> What my code does:
CLOSE: Reader
handle exception
CLOSE: Reader releases resource

>>> The context handling I expected:
CLOSE: Reader releases resource
CLOSE: Reader
handle exception

似乎将Container包装在生成器表达式中会导致在异常处理完成后清理其__iter__方法中的with块，尽管它嵌套在引发异常时被清理的另一个with块中.

为什么将Iterable包装在生成器表达式中会改变其__iter__方法内的with块在异常处理期间被终结的方式？

编辑:

感谢@user2357112的回答，我看到省略绑定到生成器表达式的局部变量可以得到我所期望的上下文处理:

def my_code_without_local():
    with closing(Reader()) as reader:
        container = Container(reader)
        for thing in (x for x in container):
            assert False

这将产生以下输出:

CLOSE: Reader releases resource
CLOSE: Reader
handle exception

这种行为真的让我感到惊讶，因为我预计命名生成器表达式container_gen中的活动with块会像my_code中的活动with块一样被清理，而不是它会挂起，只有在本地名称container_gen超出范围时才会被清理.