[SPARK-44005] Improve error messages for regular Python UDTFs that return non-tuple values

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.5.0
• Fix Version/s: 3.5.0, 4.0.0
• Component/s: PySpark
• Assignee: Allison Wang
• Reporter: Allison Wang
• Created: 08/Jun/23 05:47
• Updated: 08/Aug/23 03:10
• Resolved: 08/Aug/23 03:10

Description

Currently, if you have a UDTF like this:

class TestUDTF:
    def eval(self, a: int):
        yield a 

and run the UDTF, it will fail with a confusing error message like

Unexpected tuple 1 with StructType 

Note this works when arrow is enabled. We should improve error messages for regular UDTFs.