[C++] Cast fixed size list to compatible fixed size list type (other values type, other field name)

[asfimport]

Casting a FixedSizeListArray to a compatible type but only a different field name isn't implemented:

>>> my_type = pa.list_(pa.field("element", pa.int64()), 2)
>>> arr = pa.FixedSizeListArray.from_arrays(pa.array([1, 2, 3, 4, 5, 6]), 2)
>>> arr.type
FixedSizeListType(fixed_size_list<item: int64>[2])
>>> my_type
FixedSizeListType(fixed_size_list<element: int64>[2])

>>> arr.cast(my_type)
...
ArrowNotImplementedError: Unsupported cast from fixed_size_list<item: int64>[2] to fixed_size_list using function cast_fixed_size_list

While the similar operation with a variable sized list actually works:

>>> my_type = pa.list_(pa.field("element", pa.int64()))
>>> arr = pa.array([[1, 2], [3, 4]], pa.list_(pa.int64()))
>>> arr.type
ListType(list<item: int64>)
>>> arr.cast(my_type).type
ListType(list<element: int64>)

Reporter: Joris Van den Bossche / @jorisvandenbossche
Assignee: Kshiteej K / @kshitij12345

PRs and other links:

• GitHub Pull Request #14181

_{Note: This issue was originally created as ARROW-15479. Please see the migration documentation for further details.}

[asfimport]

Joris Van den Bossche / @jorisvandenbossche:
Also simply casting to a different but compatible type (but same field names) doesn't work:

>>> arr = pa.FixedSizeListArray.from_arrays(pa.array([1, 2, 3, 4, 5, 6]), 2)
>>> arr.type
FixedSizeListType(fixed_size_list<item: int64>[2])
>> arr.cast(pa.list_(pa.float64(), 2))
...
ArrowNotImplementedError: Unsupported cast from fixed_size_list<item: int64>[2] to fixed_size_list using function cast_fixed_size_list

And again this works for variable sized list.

[asfimport]

David Li / @lidavidm:
Issue resolved by pull request 14181
#14181