GH1579 pandas 2.0

[loicdiridollou]

Takes care of 2.0 migration issues (left in #1579):

• Construction with datetime64 or timedelta64 dtype with unsupported resolution (check allowable resolutions for pd.Series())
• Removed Series.str.iter()

[cmp0xff]

Suggested change

	assert_type(s_str.str.__iter__(), Never)
	assert_type(iter(s_str.str), Never)

[loicdiridollou]

For some reason that resolves to Any and not Never, curious if you have insights

[cmp0xff]

Here is a minimal script:

from typing import Any, Generic, Never, TypeVar, reveal_type

class Series:
    @property
    def str(self) -> StringMethods[Any, Series]: ...

_T_EXPANDING = TypeVar("_T_EXPANDING")
_T_STR = TypeVar("_T_STR", bound=Series)

class StringMethods(Generic[_T_EXPANDING, _T_STR]):
    def __getitem__(self, key: int) -> _T_STR: ...
    def __iter__(self) -> Never: ...

def _0() -> None:
    reveal_type(StringMethods().__iter__())  # all 4 type checkers give Never

def _1() -> None:
    reveal_type(iter(Series().str))  # mypy: Any, pyright, pyrefly: Never, ty: Unknown

I think it's worth reporting, but I don't have time right now. @Dr-Irv do you have further insights? I think the real use case is the proposed new version.

[loicdiridollou]

Opened astral-sh/ty#3041 to get some insights on the ty case, based on their response that may give us a hint for why mypy has issues.

[Dr-Irv]

@loicdiridollou I think you can open up one with mypy as well and see what they have to say.

[loicdiridollou]

python/mypy#21027
The example that they reduced it to on the ty thread works with mypy though:

from typing import Never, Protocol, reveal_type

class ReturnsT[T](Protocol):
    def get(self) -> T: ...

class ReturnsNever:
    def get(self) -> Never:
        raise RuntimeError

def through_protocol[T](x: ReturnsT[T]) -> T:
    return x.get()

reveal_type(through_protocol(ReturnsNever()))

with https://mypy-play.net/ but ty still struggles.