[Failing Test]: Flink 1.20 portable DataSet ValidatesRunner tests hang #40645

What happened?

A few Flink 1.20 portable DataSet tests never finish. The job stays RUNNING until waitUntilFinish hits the 20 min timeout.

This is already happening on master. #40632 skips them for DataSet only so workflow can get through, but we still need a real fix because 1.20 is LTS

The ones we’ve seen:

• CombineTest$WindowingTests.testWindowedCombineGloballyAsSingletonView
• FlattenTest.testFlattenPCollections
• MapViewTest.testMapSideInput
• ParDoTest$MultipleInputsAndOutputTests.testSameSideInputReadTwice
• ParDoTest$TimerTests.testEventTimeTimerBounded
• SplittableDoFnTest.testWindowedSideInputBounded
• ViewTest.testEmptyListSideInput

https://github.com/apache/beam/actions/runs/38961839107/job/117178555850

Issue Failure

Failure: Test is continually failing

Issue Priority

Priority: 1 (unhealthy code / failing or flaky postcommit so we cannot be sure the product is healthy)

Issue Components

• Component: Python SDK
• Component: Java SDK
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• Component: Google Cloud Dataflow Runner