[issue45588] cached_method similar to cached_property to cache with classes

[Marten Lienen]

Marten Lienen <marten.lienen at gmail.com> added the comment:

An implementation based on cached_property (that therefore also inherits its locking problem) that does not create a circular reference and copies attributes (docs etc.) from the decorated function would be as follows (based on the WeaklyBoundMethod from this PR).

def cached_method_inner(func, lru_args):
    lru_args.setdefault("maxsize", None)
    def binder(self):
        method = WeaklyBoundMethod(func.__get__(self))
        cache = lru_cache(**lru_args)
        cached = cache(method)
        update_wrapper(cached, func)
        return cached
    prop = cached_property(binder)
    update_wrapper(prop, func)
    return prop

def cached_method(func=None, /, **lru_args):
    if func is not None:
        return cached_method_inner(func, lru_args)
    else:
        def decorator(late_func):
            return cached_method_inner(late_func, lru_args)
        return decorator

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue45588>
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