[
https://issues.apache.org/jira/browse/FLINK-25513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17469027#comment-17469027
]
Dian Fu commented on FLINK-25513:
---------------------------------
[~atptour2017] Thanks for reporting this issue. Would you like to take it?
> CoFlatMapFunction requires both two flat_maps to yield something
> ----------------------------------------------------------------
>
> Key: FLINK-25513
> URL: https://issues.apache.org/jira/browse/FLINK-25513
> Project: Flink
> Issue Type: Bug
> Components: API / Python
> Affects Versions: 1.13.3
> Reporter: chendan
> Priority: Major
>
> When I used CoFlatMapFunction is pyflink, I found out that I must put yield
> something in both flat_map1 and flat_map2. Otherwise, it will raise an
> exception: TypeError: 'NoneType' object is not iterable.
> In pyflink source code: datastream.py, the process_element2 of
> KeyedCoMapCoProcessFunction class in ConnectedStreams class has only one
> sentence:
> {color:#cc7832}yield
> {color}{color:#94558d}self{color}._underlying.map2(value). if the flat_map2
> has not yield something it will result in exception. So it should judge
> whether the {color:#94558d}self{color}._underlying.map2(value) is None or not
> firstly.
--
This message was sent by Atlassian Jira
(v8.20.1#820001)
