OutputTimeFn maybe should be allowed to move elements back in time
- Dominant language
- Java
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Description
EG in this flink failure
https://builds.apache.org/job/beam_PostCommit_Java_RunnableOnService_Flink/org.apache.beam$beam-runners-flink_2.10/1749/testReport/junit/org.apache.beam.sdk.transforms.windowing/WindowTest/testNoWindowFnDoesNotReassignWindows/
Caused by: java.lang.IllegalStateException: OutputTimeFn moved element from 1970-01-01T00:00:00.015Z to earlier time 1970-01-01T00:00:00.009Z for window [1970-01-01T00:00:00.005Z..1970-01-01T00:00:00.010Z)
Imported from Jira [BEAM-1553](https://issues.apache.org/jira/browse/BEAM-1553). Original Jira may contain additional context.
Reported by: tgroh.
Contributor guide
Research direction
Start with the linked Flink failure, specifically WindowTest/testNoWindowFnDoesNotReassignWindows, and inspect the OutputTimeFn behavior that raises the IllegalStateException. Determine whether moving an element to an earlier output time is intended and define the expected windowing semantics and regression coverage before making a change.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java
- Domain
- stream-processing
- Issue type
- Bug
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100