numpy 1.21 generates issue with importing xarray

[TiemoMathijssen]

After installing numpy v1.21, I have a problem importing xarray 0.18.2 in python3.7.9. This problem does not occur using numpy v1.20.3.

Steps to reproduce:

Numpy and xarray libraries are installed using pip3 install

Error message:

Python 3.7.9 (default, Apr 30 2021, 20:11:56)
[GCC 7.3.1 20180712 (Red Hat 7.3.1-12)] on linux
Type "help", "copyright", "credits" or "license" for more information.

import xarray
Traceback (most recent call last):
File "", line 1, in
File "/home/rainbow/.local/lib/python3.7/site-packages/xarray/init.py", line 3, in
from . import testing, tutorial, ufuncs
File "/home/rainbow/.local/lib/python3.7/site-packages/xarray/testing.py", line 8, in
from xarray.core import duck_array_ops, formatting, utils
File "/home/rainbow/.local/lib/python3.7/site-packages/xarray/core/duck_array_ops.py", line 16, in
from . import dask_array_compat, dask_array_ops, dtypes, npcompat, nputils
File "/home/rainbow/.local/lib/python3.7/site-packages/xarray/core/npcompat.py", line 81, in
from numpy.typing import ArrayLike, DTypeLike
File "/home/rainbow/.local/lib/python3.7/site-packages/numpy/typing/init.py", line 315, in
from ._shape import _Shape, _ShapeLike
File "/home/rainbow/.local/lib/python3.7/site-packages/numpy/typing/_shape.py", line 15, in
_ShapeLike = Union[SupportsIndex, Sequence[SupportsIndex]]
File "/usr/lib64/python3.7/typing.py", line 254, in inner
return func(*args, **kwds)
File "/usr/lib64/python3.7/typing.py", line 634, in getitem
params = tuple(_type_check(p, msg) for p in params)
File "/usr/lib64/python3.7/typing.py", line 634, in
params = tuple(_type_check(p, msg) for p in params)
File "/usr/lib64/python3.7/typing.py", line 142, in _type_check
raise TypeError(f"{msg} Got {arg!r:.100}.")
TypeError: Parameters to generic types must be types. Got NotImplemented.

[BvB93]

Hi @TiemoMathijssen,
A fix for the issue is currently up at #19311 and should be in the next release.

In the meantime there two possible ways of remedying the situation:

• Upgrade to python >=3.8.
• Install typing-extensions.

[BvB93]

Not sure why this wasn't automatically closed by merging the linked PR.
In any case, closed by #19311.