[ARROW-15050] [Python] pyarrow.scalar doesn't accept nested pyarrow values

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Python
• Labels: python-conversion
• External issue URL: https://github.com/apache/arrow/issues/18987

Language

Python

• Assignee: Unassigned
• Reporter: Vlad Firoiu
• Created: 09/Dec/21 21:13
• Updated: 11/Jan/23 08:44

Description

Easiest explained in code:

import pyarrow as pa

t1 = pa.struct([('x', pa.int64())])
t2 = pa.struct([('y', t1)])

t1_py = {'x', 0}
t1_pa = pa.scalar(t1_py, type=t1)

t2_py = {'y': {'x': 0}}
t2_pa = pa.scalar(t2_py, type=t2)  # works

t2_mixed = {'y': t1_pa}
t2_pa_mix = pa.scalar(t2_mixed, type=t2)  # fails
assert t2_pa_mix == t2_pa

Is there some other way to construct the pyarrow struct value corresponding to t2_pa given t1_pa directly, without going through python first (i.e. constructing t1_py)?