Function generator

src/flask/helpers.py:114–136

()

        return update_wrapper(decorator, generator_or_function)  # type: ignore[arg-type]

    def generator() -> t.Iterator[t.AnyStr]:
        if (req_ctx := _cv_request.get(None)) is None:
            raise RuntimeError(
                "'stream_with_context' can only be used when a request"
                " context is active, such as in a view function."
            )

        app_ctx = _cv_app.get()
        # Setup code below will run the generator to this point, so that the
        # current contexts are recorded. The contexts must be pushed after,
        # otherwise their ContextVar will record the wrong event loop during
        # async view functions.
        yield None  # type: ignore[misc]

        # Push the app context first, so that the request context does not
        # automatically create and push a different app context.
        with app_ctx, req_ctx:
            try:
                yield from gen
            finally:
                # Clean up in case the user wrapped a WSGI iterator.
                if hasattr(gen, "close"):
                    gen.close()

    # Execute the generator to the sentinel value. This ensures the context is
    # preserved in the generator's state. Further iteration will push the