Fix PreCommit Java PVR Prism Loopback workflow

[shunping]

The PreCommit Java PVR Prism Loopback workflow failed recently due to the following error in test testMetadataPropagationParameter.

[2026-05-10T22:15:34.499261252Z]  ERROR  job failed
G job  : 
    key : job-001
    name: metadatapropagationtest0testmetadatapropagationparameter-runner-0510221530-8b8b2767
E error: 
    0: bundle inst006 stage-006 failed:org.apache.beam.sdk.coders.CoderException: java.io.EOFException: reached end of stream after reading 0 bytes; 8 bytes expected
	at org.apache.beam.sdk.coders.InstantCoder.decode(InstantCoder.java:68)
	at org.apache.beam.sdk.values.ValueInSingleWindow$Coder.decode(ValueInSingleWindow.java:166)
	at org.apache.beam.sdk.values.ValueInSingleWindow$Coder.decode(ValueInSingleWindow.java:101)
	at org.apache.beam.sdk.coders.LengthPrefixCoder.decode(LengthPrefixCoder.java:64)
	at org.apache.beam.sdk.coders.IterableLikeCoder.decode(IterableLikeCoder.java:134)
	at org.apache.beam.sdk.coders.IterableLikeCoder.decode(IterableLikeCoder.java:58)
	at org.apache.beam.sdk.coders.Coder.decode(Coder.java:164)
	at org.apache.beam.sdk.values.WindowedValues$FullWindowedValueCoder.decode(WindowedValues.java:1079)
	at org.apache.beam.sdk.values.WindowedValues$FullWindowedValueCoder.decode(WindowedValues.java:1059)
	at org.apache.beam.sdk.values.WindowedValues$FullWindowedValueCoder.decode(WindowedValues.java:985)
	at org.apache.beam.sdk.fn.data.BeamFnDataInboundObserver.multiplexElements(BeamFnDataInboundObserver.java:232)
	at org.apache.beam.sdk.fn.data.BeamFnDataInboundObserver.awaitCompletion(BeamFnDataInboundObserver.java:186)
	at org.apache.beam.fn.harness.control.ProcessBundleHandler.processBundle(ProcessBundleHandler.java:551)
	at org.apache.beam.fn.harness.control.BeamFnControlClient.delegateOnInstructionRequestType(BeamFnControlClient.java:150)
	at org.apache.beam.fn.harness.control.BeamFnControlClient$InboundObserver.lambda$onNext$0(BeamFnControlClient.java:115)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at org.apache.beam.sdk.util.UnboundedScheduledExecutorService$ScheduledFutureTask.run(UnboundedScheduledExecutorService.java:164)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.io.EOFException: reached end of stream after reading 0 bytes; 8 bytes expected
	at org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.io.ByteStreams.readFully(ByteStreams.java:802)
	at org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.io.ByteStreams.readFully(ByteStreams.java:784)
	at org.apache.beam.sdk.coders.BitConverters.readBigEndianLong(BitConverters.java:32)
	at org.apache.beam.sdk.coders.InstantCoder.decode(InstantCoder.java:64)
	... 20 more

According to the comment for testMetadataPropagationAcrossGBK, portable runners like Prism do not yet support metadata propagation across GroupByKey, enabling metadata encoding causes an EOFException coder mismatch:

beam/sdks/java/core/src/test/java/org/apache/beam/sdk/transforms/MetadataPropagationTest.java

Lines 107 to 110 in a8e7ffa

	* Tests metadata propagation across GroupByKey. Note: This test works only with DirectRunner and
	* runners that support metadata propagation (e.g. via a flag to enable metadata encoding in
	* coders). It fails on portable runners like Prism because they do not have implementation for
	* metadata propagation, leading to coder mismatches.

In testMetadataPropagationParameter, even though there is no explicit GroupByKey step, PAssert.that().containsInAnyOrder() internally introduces a GroupByKey. Therefore, we see the said error in this test as well.

Removing ValidatesRunner aligns this test with the other GBK-dependent tests in MetadataPropagationTest.

fixes #36686

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a compatibility issue in the MetadataPropagationTest suite. Because PAssert internally triggers a GroupByKey operation, it causes coder mismatch errors on portable runners that do not yet support metadata propagation across such operations. Removing the ValidatesRunner category ensures that the test suite remains stable during PreCommit workflows.

Highlights

• Test Category Update: Removed the ValidatesRunner category from the testMetadataPropagationParameter test to prevent failures on portable runners like Prism.
• Compatibility Alignment: Aligned the test with other GBK-dependent tests in the suite to ensure consistent behavior across different runner environments.

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[shunping]

r: @stankiewicz @Amar3tto

[gemini-code-assist]

Code Review

This pull request updates MetadataPropagationTest.java by adding descriptive Javadoc to the testMetadataPropagationParameter method and narrowing its test category from ValidatesRunner to NeedsRunner. The review feedback suggests refining the documentation to specify that the test requires metadata propagation support across GroupByKey operations due to the internal behavior of PAssert, and recommends adding a tracking issue for future runner support.

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