[FLINK-18836] Python UDTF doesn't work well when the return type isn't generator

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.11.0
• Fix Version/s: 1.11.3, 1.12.0
• Component/s: API / Python
• Labels: pull-request-available
• Assignee: Huang Xingbo
• Reporter: Dian Fu
• Created: 06/Aug/20 05:30
• Updated: 20/Oct/20 06:36
• Resolved: 20/Oct/20 02:27

Description

For the following Python UDTF which return type is not a generator:

# test specify the input_types
@udtf(input_types=[DataTypes.BIGINT()],
           result_types=[DataTypes.BIGINT(), DataTypes.BIGINT(), DataTypes.BIGINT()])
def split(x):
    return Row(10, 10, 10)

When used in a job, the operator containing the UDTF will not emit data to the downstream operator and there is also no exception thrown. The job just finished without any result.

We should properly handle this case: either support this use case or throw a proper exception if we don't want to support this case.

Issue Links

• links to: GitHub Pull Request #13608
• links to: GitHub Pull Request #13695