[ARROW-2128] [Python] Cannot serialize array of empty lists

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.8.0
• Fix Version/s: 0.9.0
• Component/s: Python
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/18098
• Assignee: Uwe Korn
• Reporter: Uwe Korn
• Created: 11/Feb/18 17:03
• Updated: 11/Jan/23 07:19
• Resolved: 12/Feb/18 05:39

Description

This currently failing:

data = pd.Series([[], [], []])
arr = pa.array(data)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
array.pxi:181: in pyarrow.lib.array
???
array.pxi:26: in pyarrow.lib._sequence_to_array
???
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

> ???
E pyarrow.lib.ArrowTypeError: Unable to determine data type

The code in SeqVisitor::GetType suggests that we don't want to support thus but I would have expected that the above should result in List<Null>.

Issue Links

• links to: GitHub Pull Request #1587