Files
pytorch/torch/utils/_thunk.py
Yuanyuan Chen 3cda34ebde [2/N] Apply ruff UP035 check in torch files (#164054)
This is the result of applying the ruff `UP035` check.
`Callable` is imported from `collections.abc` instead of `typing`.
`TypeAlias` is also imported from `typing`.
This PR is the follow-up of #163947.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/164054
Approved by: https://github.com/ezyang, https://github.com/Skylion007
2025-09-29 03:35:32 +00:00

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652 B
Python

from collections.abc import Callable
from typing import Generic, Optional, TypeVar
R = TypeVar("R")
class Thunk(Generic[R]):
"""
A simple lazy evaluation implementation that lets you delay
execution of a function. It properly handles releasing the
function once it is forced.
"""
f: Optional[Callable[[], R]]
r: Optional[R]
__slots__ = ["f", "r"]
def __init__(self, f: Callable[[], R]):
self.f = f
self.r = None
def force(self) -> R:
if self.f is None:
return self.r # type: ignore[return-value]
self.r = self.f()
self.f = None
return self.r