Enforce deterministic field order in Schema generated from KafkaIO classes.

[baeminbo]

To prevent potential serialization issues, this change adds the @SchemaFieldNumber annotation to KafkaIO classes that use DefaultSchema. This guarantees a deterministic field order, which is not ensured when schemas are generated with AutoValueSchema, JavaBeanSchema, or JavaFieldSchema.

related to: #30276, b/443606305#comment29

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[gemini-code-assist]

Summary of Changes

Hello @baeminbo, 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 enhances the robustness of Apache Beam's KafkaIO component by ensuring that schemas generated for its internal classes maintain a deterministic field order. By explicitly defining the field numbering through annotations, the change mitigates potential serialization inconsistencies and improves the reliability of data processing with KafkaIO. Additionally, new tests have been added to validate these schema generations.

Highlights

• Deterministic Schema Field Order: Introduced @SchemaFieldNumber annotations to various KafkaIO-related classes (ErrorHandling, KafkaIO.KafkaHeader, KafkaIO.ByteArrayKafkaRecord, KafkaReadSchemaTransformConfiguration, KafkaSourceDescriptor, KafkaWriteSchemaTransformConfiguration) to ensure a consistent field order when schemas are generated using DefaultSchema. This addresses potential serialization issues that can arise from non-deterministic field ordering in AutoValueSchema, JavaBeanSchema, or JavaFieldSchema.
• Schema Verification Tests: Added new unit tests (testByteArrayKafkaRecordSchema, testKafkaSourceDescriptorSchema, testKafkaHeaderSchema, testKafkaReadSchemaTransformConfigurationSchema, testKafkaWriteSchemaTransformConfigurationSchema) to explicitly verify the correctness and deterministic nature of the generated schemas for the affected KafkaIO classes.

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[github-actions]

Checks are failing. Will not request review until checks are succeeding. If you'd like to override that behavior, comment assign set of reviewers

[baeminbo]

Run Java PreCommit

[github-actions]

Assigning reviewers:

R: @ahmedabu98 for label java.
R: @fozzie15 for label kafka.

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[github-actions]

Reminder, please take a look at this pr: @ahmedabu98@fozzie15

[github-actions]

Assigning new set of reviewers because Pr has gone too long without review. If you would like to opt out of this review, comment assign to next reviewer:

R: @Abacn for label java.
R: @johnjcasey for label kafka.

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[Abacn]

@tomstepp@johnjcasey could take a look?

[tomstepp]

LGTM in general. Assuming pipelines are update compatible across this change? @baeminbo

[baeminbo]

LGTM in general. Assuming pipelines are update compatible across this change? @baeminbo

Yes, right. Currently, this issue can randomly corrupt the states persisted in storage with SchemaCoder at job update, thus the replacement job will encounter unrecoverable problems in deserializing the states from the original job.

[tomstepp]

To clarify, it sounds like this does fix updates where the original pipeline includes this change. But I was not sure if it works with original pipeline on an SDK version before this change upgrading to newer SDK version with this change. Would the original order be incompatible with the new enforced order?

[tomstepp]

@johnjcasey or @an2x would you have any additional feedback?

[reuvenlax]

LGTM

[Abacn]

This breaks PythonUdingJavaSQL tests:
https://github.com/apache/beam/actions/workflows/beam_PostCommit_XVR_PythonUsingJavaSQL_Dataflow.yml?query=event%3Aschedule

test_streaming_taxifare_prediction_yaml (apache_beam.yaml.examples.testing.examples_test.MLTest) failed
test_map_to_fields_with_java_deps_yaml (apache_beam.yaml.examples.testing.examples_test.ElementWiseTest) failed

#30593#30517#31418

ValueError: Error applying transform "WriteKafka" at line 131: java.lang.UnsupportedOperationException: Unknown urn: beam:schematransform:org.apache.beam:yaml:map_to_fields-java:v1
at org.apache.beam.sdk.expansion.service.ExpansionService.expand(ExpansionService.java:648)
at org.apache.beam.sdk.expansion.service.ExpansionService.expand(ExpansionService.java:758)
at org.apache.beam.model.expansion.v1.ExpansionServiceGrpc$MethodHandlers.invoke(ExpansionServiceGrpc.java:306)

[chamikaramj]

Seems like this also broke Managed I/O for Kafka (Google internal test)

Failed to upgrade using the expansion service manager: INTERNAL: Expansion request failed: java.lang.IllegalStateException: Expected field number 3 for field + redistributeNumKeys instead got 2"

Can we revert ?

[reuvenlax]

Do we know the Managed Kafka test expects specific field numbers? These classes already had unstable field numbers that were liable to change - this PR fixed that.

…

On Mon, Oct 13, 2025 at 10:18 AM Chamikara Jayalath < ***@***.***> wrote: *chamikaramj* left a comment (apache/beam#36295) <#36295 (comment)> Seems like this also broke Managed I/O for Kafka (Google internal test) Failed to upgrade using the expansion service manager: INTERNAL: Expansion request failed: java.lang.IllegalStateException: Expected field number 3 for field + redistributeNumKeys instead got 2" Can we revert ? — Reply to this email directly, view it on GitHub <#36295 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFAYJVJICPBLS72E5DH5LPT3XPNFDAVCNFSM6AAAAACHSAZFNGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTGOJYGQYTAMZUG4> . You are receiving this because you modified the open/close state.Message ID: ***@***.***>

[chamikaramj]

Managed I/O uses a Beam construction Row (shema-aware transform) generated from old Beam versions to upgrade Kafka to newer Beam versions. So my suspicion is that that Row is now incompatible with the new Beam Kafka I/O version so we cannot upgrade. That test has been very stable historically in my experience (over last 10 Beam versions).

May be we can add a guard against old Beam versions using the updateCompatibilityBeamVersion option [1] ? (which is always set for Managed I/O)

beam/sdks/java/core/src/main/java/org/apache/beam/sdk/options/StreamingOptions.java

Line 45 in 1c6f779

StringgetUpdateCompatibilityVersion();

[chamikaramj]

Full stack-trace:

INFO 2025-10-13T15:36:48.915770337Z E1013 15:36:48.792550 14 managed_transforms_worker_main.cc:272] Failed to upgrade using the expansion service manager: INTERNAL: Expansion request failed: java.lang.IllegalStateException: Expected field number 3 for field + redistributeNumKeys instead got 2
INFO 2025-10-13T15:36:48.915774910Z at org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkState(Preconditions.java:512)
INFO 2025-10-13T15:36:48.915782126Z at org.apache.beam.sdk.schemas.AutoValueSchema.validateFieldNumbers(AutoValueSchema.java:80)
INFO 2025-10-13T15:36:48.915786418Z at org.apache.beam.sdk.schemas.AutoValueSchema.access$000(AutoValueSchema.java:38)
INFO 2025-10-13T15:36:48.915790340Z at org.apache.beam.sdk.schemas.AutoValueSchema$AbstractGetterTypeSupplier.get(AutoValueSchema.java:68)
INFO 2025-10-13T15:36:48.915795972Z at org.apache.beam.sdk.schemas.utils.StaticSchemaInference.schemaFromClass(StaticSchemaInference.java:107)
INFO 2025-10-13T15:36:48.915802211Z at org.apache.beam.sdk.schemas.utils.StaticSchemaInference.schemaFromClass(StaticSchemaInference.java:89)
INFO 2025-10-13T15:36:48.915806181Z at org.apache.beam.sdk.schemas.utils.JavaBeanUtils.schemaFromJavaBeanClass(JavaBeanUtils.java:79)
INFO 2025-10-13T15:36:48.915810433Z at org.apache.beam.sdk.schemas.AutoValueSchema.schemaFor(AutoValueSchema.java:146)
INFO 2025-10-13T15:36:48.915815235Z at org.apache.beam.sdk.schemas.annotations.DefaultSchema$DefaultSchemaProvider.schemaFor(DefaultSchema.java:148)
INFO 2025-10-13T15:36:48.915837462Z at org.apache.beam.sdk.schemas.SchemaRegistry.lambda$getSchema$0(SchemaRegistry.java:245)
INFO 2025-10-13T15:36:48.915842880Z at org.apache.beam.sdk.schemas.SchemaRegistry.getProviderResult(SchemaRegistry.java:331)
INFO 2025-10-13T15:36:48.915847526Z at org.apache.beam.sdk.schemas.SchemaRegistry.getSchema(SchemaRegistry.java:245)
INFO 2025-10-13T15:36:48.915853469Z at org.apache.beam.sdk.schemas.SchemaRegistry.getSchema(SchemaRegistry.java:233)
INFO 2025-10-13T15:36:48.915857238Z at org.apache.beam.sdk.schemas.transforms.TypedSchemaTransformProvider.configurationSchema(TypedSchemaTransformProvider.java:96)
INFO 2025-10-13T15:36:48.915860690Z at org.apache.beam.sdk.managed.ManagedSchemaTransformProvider$ManagedSchemaTransform.<init>(ManagedSchemaTransformProvider.java:163)
INFO 2025-10-13T15:36:48.915865414Z at org.apache.beam.sdk.managed.ManagedSchemaTransformProvider.from(ManagedSchemaTransformProvider.java:152)
INFO 2025-10-13T15:36:48.915869461Z at org.apache.beam.sdk.managed.ManagedSchemaTransformProvider.from(ManagedSchemaTransformProvider.java:57)
INFO 2025-10-13T15:36:48.915873575Z at org.apache.beam.sdk.schemas.transforms.TypedSchemaTransformProvider.from(TypedSchemaTransformProvider.java:111)
INFO 2025-10-13T15:36:48.915878155Z at org.apache.beam.sdk.expansion.service.ExpansionServiceSchemaTransformProvider.getTransform(ExpansionServiceSchemaTransformProvider.java:137)
INFO 2025-10-13T15:36:48.915882745Z at org.apache.beam.sdk.expansion.service.ExpansionService$TransformProviderForPayloadTranslator.getTransform(ExpansionService.java:263)
INFO 2025-10-13T15:36:48.915888115Z at org.apache.beam.sdk.expansion.service.TransformProvider.apply(TransformProvider.java:121)
INFO 2025-10-13T15:36:48.915891688Z at org.apache.beam.sdk.expansion.service.ExpansionService.expand(ExpansionService.java:657)
INFO 2025-10-13T15:36:48.915896062Z at org.apache.beam.sdk.expansion.service.ExpansionService.expand(ExpansionService.java:758)
INFO 2025-10-13T15:36:48.915914630Z at org.apache.beam.model.expansion.v1.ExpansionServiceGrpc$MethodHandlers.invoke(ExpansionServiceGrpc.java:306)
INFO 2025-10-13T15:36:48.915951892Z at org.apache.beam.vendor.grpc.v1p69p0.io.grpc.stub.ServerCalls$UnaryServerCallHandler$UnaryServerCallListener.onHalfClose(ServerCalls.java:182)
INFO 2025-10-13T15:36:48.915960032Z at org.apache.beam.vendor.grpc.v1p69p0.io.grpc.internal.ServerCallImpl$ServerStreamListenerImpl.halfClosed(ServerCallImpl.java:356)
INFO 2025-10-13T15:36:48.915964459Z at org.apache.beam.vendor.grpc.v1p69p0.io.grpc.internal.ServerImpl$JumpToApplicationThreadServerStreamListener$1HalfClosed.runInContext(ServerImpl.java:861)
INFO 2025-10-13T15:36:48.915968683Z at org.apache.beam.vendor.grpc.v1p69p0.io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
INFO 2025-10-13T15:36:48.915972398Z at org.apache.beam.vendor.grpc.v1p69p0.io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
INFO 2025-10-13T15:36:48.915976930Z at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
INFO 2025-10-13T15:36:48.915998564Z at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
INFO 2025-10-13T15:36:48.916002886Z at java.base/java.lang.Thread.run(Thread.java:829)

[chamikaramj]

BTW we also sort fields when performing the schema-transform expansion:

beam/sdks/java/io/kafka/src/main/java/org/apache/beam/sdk/io/kafka/KafkaReadSchemaTransformProvider.java

Line 155 in 1c6f779

.sorted()

cc: @ahmedabu98

[chamikaramj]

Created a release blocker #36496 for tracking.

[baeminbo]

The broken PythonUdingJavaSQL tests were fixed by #36489, which sets SchemaFieldNumber for the fields in KafkaReadSchemaTransformConfiguration missed in this PR.