Skip to content

lru-cache-with-maxsize-none (UP033)#

Derived from the pyupgrade linter.

Fix is always available.

What it does#

Checks for uses of functools.lru_cache that set maxsize=None.

Why is this bad?#

Since Python 3.9, functools.cache can be used as a drop-in replacement for functools.lru_cache(maxsize=None). When possible, prefer functools.cache as it is more readable and idiomatic.

Example#

import functools


@functools.lru_cache(maxsize=None)
def foo(): ...

Use instead:

import functools


@functools.cache
def foo(): ...

Options#

References#