[ARROW-17839] [Python] Cannot create RecordBatch with nested struct containing extension type

• Type: Bug
• Status: Open
• Priority: Blocker
• Resolution: Unresolved
• Affects Version/s: 9.0.0
• Component/s: Python
• Environment: macOS 12.5.1 on an Apple M1 Ultra.
• External issue URL: https://github.com/apache/arrow/issues/33059
• Assignee: Unassigned
• Reporter: Matthias Vallentin
• Created: 25/Sep/22 09:30
• Updated: 11/Jan/23 11:56

Description

I'm running into the following issue:

pyarrow.lib.ArrowNotImplementedError: Unsupported cast to extension<vast.address<AddressType>> from fixed_size_binary[16]

Use case: I want to create a record batch that contains this type:

pa.struct([("address", AddressType()), ("length", pa.uint8())])

Here, AddressType is an extension type that models an IP address (pa.binary(16)).

Please find attached a self-contained example that illustrates the issue.