Replace plain slice type hints with IndexSlice.

[randolf-scholz]

Trying to see what happens when we replace slice type hints with

IndexSlice: TypeAlias = slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None]

annotations.

[brianschubert]

This seems like a good improvement to me. I imagine this would be very nice for replacing mypy's hardcoded SupportsIndex/None checks for slice indices (python/mypy#2410).

It looks like the pytype errors may be due to pytype having its own builtins stubs, which don't define slice as being generic: https://github.com/google/pytype/blob/97d949161b27259af283fc1d271f8cf056ddf9b6/pytype/stubs/builtins/builtins.pytd#L972

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

streamlit (https://github.com/streamlit/streamlit)
- lib/tests/streamlit/elements/lib/column_config_utils_test.py:385:13: note:     def __getitem__(self, Union[SupportsIndex, slice[Any, Any, Any]], /) -> str
+ lib/tests/streamlit/elements/lib/column_config_utils_test.py:385:13: note:     def __getitem__(self, Union[SupportsIndex, slice[Optional[SupportsIndex], Optional[SupportsIndex], Optional[SupportsIndex]]], /) -> str
- lib/tests/streamlit/runtime/state/query_params_test.py:264:37: note:         def __getitem__(self, slice[Any, Any, Any], /) -> Tuple[Any, ...]
+ lib/tests/streamlit/runtime/state/query_params_test.py:264:37: note:         def __getitem__(self, slice[Optional[SupportsIndex], Optional[SupportsIndex], Optional[SupportsIndex]], /) -> Tuple[Any, ...]

prefect (https://github.com/PrefectHQ/prefect)
- src/prefect/cli/deploy.py:1144: note:     def __setitem__(self, slice[Any, Any, Any], Iterable[dict[Any, Any]], /) -> None
+ src/prefect/cli/deploy.py:1144: note:     def __setitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], Iterable[dict[Any, Any]], /) -> None
- src/prefect/cli/deploy.py:1170: note:     def __setitem__(self, slice[Any, Any, Any], Iterable[dict[Any, Any]], /) -> None
+ src/prefect/cli/deploy.py:1170: note:     def __setitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], Iterable[dict[Any, Any]], /) -> None
- src/prefect/cli/deploy.py:1178: note:     def __setitem__(self, slice[Any, Any, Any], Iterable[dict[Any, Any]], /) -> None
+ src/prefect/cli/deploy.py:1178: note:     def __setitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], Iterable[dict[Any, Any]], /) -> None
- src/prefect/cli/deploy.py:1195: note:     def __getitem__(self, slice[Any, Any, Any], /) -> list[dict[Any, Any]]
+ src/prefect/cli/deploy.py:1195: note:     def __getitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> list[dict[Any, Any]]

speedrun.com_global_scoreboard_webapp (https://github.com/Avasam/speedrun.com_global_scoreboard_webapp)
- backend/api/tournament_scheduler_api.py:327: note:     def __getitem__(self, slice[Any, Any, Any], /) -> list[Any]
+ backend/api/tournament_scheduler_api.py:327: note:     def __getitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> list[Any]
- backend/api/tournament_scheduler_api.py:331: note:     def __getitem__(self, slice[Any, Any, Any], /) -> list[Any]
+ backend/api/tournament_scheduler_api.py:331: note:     def __getitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> list[Any]
- backend/api/tournament_scheduler_api.py:335: note:     def __getitem__(self, slice[Any, Any, Any], /) -> list[Any]
+ backend/api/tournament_scheduler_api.py:335: note:     def __getitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> list[Any]

operator (https://github.com/canonical/operator)
- ops/framework.py:1304: note:          def __getitem__(self, slice[Any, Any, Any], /) -> MutableSequence[Any]
+ ops/framework.py:1304: note:          def __getitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> MutableSequence[Any]
- ops/framework.py:1304: note:          def __getitem__(self, slice[Any, Any, Any], /) -> Sequence[Any]
+ ops/framework.py:1304: note:          def __getitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> Sequence[Any]
- ops/framework.py:1307: note:          def __setitem__(self, slice[Any, Any, Any], Iterable[Any], /) -> None
+ ops/framework.py:1307: note:          def __setitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], Iterable[Any], /) -> None
- ops/framework.py:1311: note:          def __delitem__(self, slice[Any, Any, Any], /) -> None
+ ops/framework.py:1311: note:          def __delitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> None

discord.py (https://github.com/Rapptz/discord.py)
- discord/http.py:235: note:     def __setitem__(self, slice[Any, Any, Any], Iterable[Embed], /) -> None
+ discord/http.py:235: note:     def __setitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], Iterable[Embed], /) -> None

dd-trace-py (https://github.com/DataDog/dd-trace-py)
- ddtrace/settings/config.py:905: note:     def __getitem__(self, SupportsIndex | slice[Any, Any, Any], /) -> str
+ ddtrace/settings/config.py:905: note:     def __getitem__(self, SupportsIndex | slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> str

manticore (https://github.com/trailofbits/manticore)
- tests/wasm/json2mc.py:103: note:     def __getitem__(self, slice[Any, Any, Any], /) -> list[Any]
+ tests/wasm/json2mc.py:103: note:     def __getitem__(self, slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None], /) -> list[Any]

[srittau]

Closing in favor of #13008.

[randolf-scholz]

@srittau This PR is not in conflict with #13008, it is for making some annotations in the stubs more precise by replacing slice[Any, Any, Any] with more concrete types.

Thanks to #13008, one could now use slice[SupportsIndex | None] instead of an alias, since it will default to slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None].