view mercurial/thirdparty/attr/setters.pyi @ 51234:59183a19954e

rust-index: use interior mutability in head revs and caches

For upcoming changes in `hg-cpython` switching to the `hg-core` index in
ancestors iterators, we will need to avoid excessive mutability, restricting
the use of mutable references on `hg::index::Index` to methods that actually
logically mutate it, whereas the maintenance of caches such as `head_revs`
clearly does not. We illustrate that immediately by switching to immutable
borrows in the corresponding methods of `hg-cpython::MixedIndex`

from typing import Any, NewType, NoReturn, TypeVar, cast

from . import Attribute, _OnSetAttrType

_T = TypeVar("_T")

def frozen(
    instance: Any, attribute: Attribute[Any], new_value: Any
) -> NoReturn: ...
def pipe(*setters: _OnSetAttrType) -> _OnSetAttrType: ...
def validate(instance: Any, attribute: Attribute[_T], new_value: _T) -> _T: ...

# convert is allowed to return Any, because they can be chained using pipe.
def convert(
    instance: Any, attribute: Attribute[Any], new_value: Any
) -> Any: ...

_NoOpType = NewType("_NoOpType", object)
NO_OP: _NoOpType