from __future__ import annotations

from collections.abc import Iterator

from contextlib import contextmanager

from typing import Final

from mypy.checker_shared import TypeCheckerSharedApi

# This is global mutable state. Don't add anything here unless there's a very

# good reason.

class TypeCheckerState:

# Wrap this in a class since it's faster that using a module-level attribute.

def __init__(self, type_checker: TypeCheckerSharedApi | None) -> None:

# Value varies by file being processed

self.type_checker = type_checker

@contextmanager

def set(self, value: TypeCheckerSharedApi) -> Iterator[None]:

saved = self.type_checker

self.type_checker = value

try:

yield

finally:

self.type_checker = saved

checker_state: Final = TypeCheckerState(type_checker=None)