[Python]pa.FixedShapeTensorArray.to_numpy_ndarray fails on sliced arrays

[mariosasko]

Describe the bug, including details regarding any error messages, version, and platform.

MRE:

import pyarrow as pa
import numpy as np
np_arr = np.random.randn(100, 3, 4)
pa_arr = pa.FixedShapeTensorArray.from_numpy_ndarray(np_arr)
pa_arr[:2].to_numpy_ndarray()

The error stems from the following line:

arrow/python/pyarrow/array.pxi

Line 3156 in cd6e2a4

np_flat = np.asarray(self.storage.values)

(.values ignores the slicing offset)

Component(s)

Python

[AlenkaF]

Thank you for reporting the issue!
You are correct. It seems .storage holds the correct sliced part of the array and .storage.values does not:

(Pdb) len(pa_arr.storage.values)
1200
(Pdb) len(pa_arr.storage)
100

So this looks like a bug in pyarrow.FixedSizeListArray.values:

>>> import pyarrow as pa
>>> arr = pa.array([[1, 2, 3], [], None, [4]], type=pa.list_(pa.int32()))
>>> arr.values
<pyarrow.lib.Int32Array object at 0x128665f60>
[
  1,
  2,
  3,
  4
]
>>> arr[:2].values
<pyarrow.lib.Int32Array object at 0x1286661a0>
[
  1,
  2,
  3,
  4
]

I think this issue #35360 has the same underlying problem.