BUG: Subtraction fails with matching index of different name and type

[Bjoern-Rapp]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd

s1 = pd.Series(
    [23, 22, 21], index=pd.Index(["a", "b", "c"], name="index a"), dtype=pd.Int64Dtype()
)
s2 = pd.Series(
    [21, 22, 23],
    index=pd.Index(["a", "b", "c"], name="index b", dtype=pd.StringDtype()),
    dtype=pd.Int64Dtype(),
)

s1 - s2

Issue Description

This example with two series with a nullable integer data type and a index with different names and of differing data types, on with a nullable string datatype and object datatype fails with and error from pandas._libs.algos.ensure_platform_int()

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[170], line 10
      1 s1 = pd.Series(
      2     [23, 22, 21], index=pd.Index(["a", "b", "c"], name="index a"), dtype=pd.Int64Dtype()
      3 )
      4 s2 = pd.Series(
      5     [21, 22, 23],
      6     index=pd.Index(["a", "b", "c"], name="index b", dtype=pd.StringDtype()),
      7     dtype=pd.Int64Dtype(),
      8 )
---> 10 s1 - s2

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/ops/common.py:76, in _unpack_zerodim_and_defer.<locals>.new_method(self, other)
     72             return NotImplemented
     74 other = item_from_zerodim(other)
---> 76 return method(self, other)

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/arraylike.py:194, in OpsMixin.__sub__(self, other)
    192 @unpack_zerodim_and_defer("__sub__")
    193 def __sub__(self, other):
--> 194     return self._arith_method(other, operator.sub)

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/series.py:5814, in Series._arith_method(self, other, op)
   5813 def _arith_method(self, other, op):
-> 5814     self, other = self._align_for_op(other)
   5815     return base.IndexOpsMixin._arith_method(self, other, op)

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/series.py:5844, in Series._align_for_op(self, right, align_asobject)
   5841             left = left.astype(object)
   5842             right = right.astype(object)
-> 5844         left, right = left.align(right, copy=False)
   5846 return left, right

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/generic.py:10095, in NDFrame.align(self, other, join, axis, level, copy, fill_value, method, limit, fill_axis, broadcast_axis)
  10082     left, _right, join_index = self._align_frame(
  10083         other,
  10084         join=join,
   (...)
  10091         fill_axis=fill_axis,
  10092     )
  10094 elif isinstance(other, ABCSeries):
> 10095     left, _right, join_index = self._align_series(
  10096         other,
  10097         join=join,
  10098         axis=axis,
  10099         level=level,
  10100         copy=copy,
  10101         fill_value=fill_value,
  10102         method=method,
  10103         limit=limit,
  10104         fill_axis=fill_axis,
  10105     )
  10106 else:  # pragma: no cover
  10107     raise TypeError(f"unsupported type: {type(other)}")

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/generic.py:10224, in NDFrame._align_series(self, other, join, axis, level, copy, fill_value, method, limit, fill_axis)
  10221         new_mgr = self._mgr.reindex_indexer(join_index, lidx, axis=1, copy=copy)
  10222         left = self._constructor_from_mgr(new_mgr, axes=new_mgr.axes)
> 10224     right = other._reindex_indexer(join_index, ridx, copy)
  10226 else:
  10227     # one has > 1 ndim
  10228     fdata = self._mgr

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/series.py:4779, in Series._reindex_indexer(self, new_index, indexer, copy)
   4776         return self.copy(deep=copy)
   4777     return self
-> 4779 new_values = algorithms.take_nd(
   4780     self._values, indexer, allow_fill=True, fill_value=None
   4781 )
   4782 return self._constructor(new_values, index=new_index, copy=False)

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/array_algos/take.py:115, in take_nd(arr, indexer, axis, fill_value, allow_fill)
    110         arr = cast("NDArrayBackedExtensionArray", arr)
    111         return arr.take(
    112             indexer, fill_value=fill_value, allow_fill=allow_fill, axis=axis
    113         )
--> 115     return arr.take(indexer, fill_value=fill_value, allow_fill=allow_fill)
    117 arr = np.asarray(arr)
    118 return _take_nd_ndarray(arr, indexer, axis, fill_value, allow_fill)

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/arrays/masked.py:905, in BaseMaskedArray.take(self, indexer, allow_fill, fill_value, axis)
    894 def take(
    895     self,
    896     indexer,
   (...)
    902     # we always fill with 1 internally
    903     # to avoid upcasting
    904     data_fill_value = self._internal_fill_value if isna(fill_value) else fill_value
--> 905     result = take(
    906         self._data,
    907         indexer,
    908         fill_value=data_fill_value,
    909         allow_fill=allow_fill,
    910         axis=axis,
    911     )
    913     mask = take(
    914         self._mask, indexer, fill_value=True, allow_fill=allow_fill, axis=axis
    915     )
    917     # if we are filling
    918     # we only fill where the indexer is null
    919     # not existing missing values
    920     # TODO(jreback) what if we have a non-na float as a fill value?

File ~/beftett/.venv/lib/python3.10/site-packages/pandas/core/algorithms.py:1309, in take(arr, indices, axis, allow_fill, fill_value)
   1306 if not is_array_like(arr):
   1307     arr = np.asarray(arr)
-> 1309 indices = ensure_platform_int(indices)
   1311 if allow_fill:
   1312     # Pandas style, -1 means NA
   1313     validate_indices(indices, arr.shape[axis])

File pandas/_libs/algos_common_helper.pxi:22, in pandas._libs.algos.ensure_platform_int()

TypeError: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'

If any of these three conditions is removed, the subtraction succeeds.

Expected Behavior

The subtraction should succeed.

Installed Versions

commit: 2a953cf
python: 3.10.9.final.0
python-bits : 64
OS : Linux
OS-release : 5.15.133+
Version : #1 SMP Sat Dec 30 11:18:04 UTC 2023
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : en_US.UTF-8
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8
pandas : 2.1.3
numpy : 1.24.4
pytz : 2023.3.post1
dateutil : 2.8.2
setuptools : 69.0.3
pip : 23.2.1
Cython : None
pytest : 7.4.4
hypothesis : 6.91.0
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : 5.0.0
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.2
IPython : 8.19.0
pandas_datareader : None
bs4 : 4.12.2
bottleneck : None
dataframe-api-compat: None
fastparquet : None
fsspec : 2023.12.2
gcsfs : 2023.12.2post1
matplotlib : 3.8.2
numba : 0.57.1
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 13.0.0
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : 1.11.4
sqlalchemy : 2.0.24
tables : None
tabulate : None
xarray : 2023.8.0
xlrd : None
zstandard : None
tzdata : 2023.4
qtpy : None
pyqt5 : None

[rhshadrach]

Thanks for the report. Might be related to #45564 - cc @phofl.

pandas/pandas/core/series.py

Lines 4637 to 4646 in 9530851

	# Note: new_index is None iff indexer is None
	# if not None, indexer is np.intp
	if indexer is None and (
	new_index is None or new_index.names == self.index.names
	):
	return self.copy(deep=False)
	new_values = algorithms.take_nd(
	self._values, indexer, allow_fill=True, fill_value=None
	)

Prior to this PR, we would not call take_nd when indexer is None. Now we might be passing indexer=None to take_nd. For NumPy arrays, we end up in _take_nd_array which has the lines:

pandas/pandas/core/array_algos/take.py

Lines 127 to 129 in 9530851

	if indexer is None:
	indexer = np.arange(arr.shape[axis], dtype=np.intp)
	dtype, fill_value = arr.dtype, arr.dtype.type()

but no such logic exists for EAs. Perhaps it should?

[Adasjo]

take

[CasperKristiansson]

take

[VictorOsterman]

take

[Tobiky]

take