remove nep18 compatibility code (#5064)

Author: keewis

xarray/core/npcompat.py

@@ -84,21 +84,6 @@ def moveaxis(a, source, destination):
     DTypeLike = Union[np.dtype, str]  # type: ignore
 
 
-# from dask/array/utils.py
-def _is_nep18_active():
-    class A:
-        def __array_function__(self, *args, **kwargs):
-            return True
-
-    try:
-        return np.concatenate([A()])
-    except ValueError:
-        return False
-
-
-IS_NEP18_ACTIVE = _is_nep18_active()
-
-
 if LooseVersion(np.__version__) >= "1.20.0":
     sliding_window_view = np.lib.stride_tricks.sliding_window_view
 else:

xarray/core/variable.py

@@ -32,7 +32,6 @@
     VectorizedIndexer,
     as_indexable,
 )
-from .npcompat import IS_NEP18_ACTIVE
 from .options import _get_keep_attrs
 from .pycompat import (
     cupy_array_type,
@@ -242,16 +241,7 @@ def as_compatible_data(data, fastpath=False):
 
     if not isinstance(data, np.ndarray):
         if hasattr(data, "__array_function__"):
-            if IS_NEP18_ACTIVE:
-                return data
-            else:
-                raise TypeError(
-                    "Got an NumPy-like array type providing the "
-                    "__array_function__ protocol but NEP18 is not enabled. "
-                    "Check that numpy >= v1.16 and that the environment "
-                    'variable "NUMPY_EXPERIMENTAL_ARRAY_FUNCTION" is set to '
-                    '"1"'
-                )
+            return data
 
     # validate whether the data is valid data types.
     data = np.asarray(data)

xarray/tests/test_dataset.py

@@ -28,7 +28,6 @@
 from xarray.coding.cftimeindex import CFTimeIndex
 from xarray.core import dtypes, indexing, utils
 from xarray.core.common import duck_array_ops, full_like
-from xarray.core.npcompat import IS_NEP18_ACTIVE
 from xarray.core.pycompat import integer_types
 from xarray.core.utils import is_scalar
 
@@ -320,7 +319,6 @@ def test_unicode_data(self):
         actual = str(data)
         assert expected == actual
 
-    @pytest.mark.skipif(not IS_NEP18_ACTIVE, reason="requires __array_function__")
     def test_repr_nep18(self):
         class Array:
             def __init__(self):

xarray/tests/test_formatting.py

@@ -7,7 +7,6 @@
 
 import xarray as xr
 from xarray.core import formatting
-from xarray.core.npcompat import IS_NEP18_ACTIVE
 
 from . import raises_regex
 
@@ -395,7 +394,6 @@ def test_array_repr(self):
         assert actual == expected
 
 
-@pytest.mark.skipif(not IS_NEP18_ACTIVE, reason="requires __array_function__")
 def test_inline_variable_array_repr_custom_repr():
     class CustomArray:
         def __init__(self, value, attr):

xarray/tests/test_sparse.py

@@ -8,19 +8,13 @@
 import xarray as xr
 import xarray.ufuncs as xu
 from xarray import DataArray, Variable
-from xarray.core.npcompat import IS_NEP18_ACTIVE
 from xarray.core.pycompat import sparse_array_type
 
 from . import assert_equal, assert_identical, requires_dask
 
 param = pytest.param
 xfail = pytest.mark.xfail
 
-if not IS_NEP18_ACTIVE:
-    pytest.skip(
-        "NUMPY_EXPERIMENTAL_ARRAY_FUNCTION is not enabled", allow_module_level=True
-    )
-
 sparse = pytest.importorskip("sparse")
 
 

xarray/tests/test_testing.py

@@ -4,7 +4,6 @@
 import pytest
 
 import xarray as xr
-from xarray.core.npcompat import IS_NEP18_ACTIVE
 
 from . import has_dask
 
@@ -99,10 +98,6 @@ def test_assert_duckarray_equal_failing(duckarray, obj1, obj2):
         pytest.param(
             np.array,
             id="numpy",
-            marks=pytest.mark.skipif(
-                not IS_NEP18_ACTIVE,
-                reason="NUMPY_EXPERIMENTAL_ARRAY_FUNCTION is not enabled",
-            ),
         ),
         pytest.param(
             dask_from_array,

xarray/tests/test_units.py

@@ -7,7 +7,6 @@
 
 import xarray as xr
 from xarray.core import dtypes
-from xarray.core.npcompat import IS_NEP18_ACTIVE
 
 from . import assert_allclose, assert_duckarray_allclose, assert_equal, assert_identical
 from .test_variable import _PAD_XR_NP_ARGS
@@ -23,9 +22,6 @@
 
 
 pytestmark = [
-    pytest.mark.skipif(
-        not IS_NEP18_ACTIVE, reason="NUMPY_EXPERIMENTAL_ARRAY_FUNCTION is not enabled"
-    ),
     pytest.mark.filterwarnings("error::pint.UnitStrippedWarning"),
 ]