PR Stack (Queue Instrumentation)

• feat(core): [Queue Instrumentation 1] Add enableQueueTracing option and messaging span data conventions #5250
• feat(samples): [Queue Instrumentation 2] Add Kafka to Spring Boot 3 sample app #5253
• feat(spring-jakarta): [Queue Instrumentation 3] Add Kafka producer instrumentation #5254
• feat(spring-jakarta): [Queue Instrumentation 4] Add Kafka consumer instrumentation #5255
• feat(spring-boot-jakarta): [Queue Instrumentation 5] Add Kafka queue auto-configuration #5259
• test(samples): [Queue Instrumentation 6] Add Kafka queue system tests #5260
• feat(samples): [Queue Instrumentation 7] Add Kafka to Spring Boot 3 OTel sample apps #5265
• fix(spring-boot-jakarta): [Queue Instrumentation 8] Disable Sentry Kafka spans when OTel is active #5274
• fix(spring-jakarta): [Queue Instrumentation 9] Clean up stale ThreadLocal context in Kafka consumer interceptor #5279
• fix(spring-jakarta): [Queue Instrumentation 10] Fork root scopes and skip when OTel is active in Kafka consumer #5280
• fix(spring-jakarta): [Queue Instrumentation 11] Guard entire span lifecycle in Kafka producer interceptor #5281
• fix(spring-jakarta): [Queue Instrumentation 12] Add Kafka retry count attribute #5282
• fix(spring-jakarta): [Queue Instrumentation 13] Align enqueue time with Python #5283
• ref(kafka): [Queue Instrumentation 14] Extract sentry-kafka module #5288
• feat(samples): [Queue Instrumentation 15] Add opt-in Kafka console e2e coverage #5289
• fix(test): [Queue Instrumentation 16] Enable Kafka profile in system runner #5291
• feat(kafka): [Queue Instrumentation 17] Add manual consumer tracing helper #5312
• ref(samples): [Queue Instrumentation 18] Move Kafka sources into queues.kafka package #5313
• ref(samples): [Queue Instrumentation 19] Drop Kafka auto-config exclude from Spring Boot samples #5314
• ref(kafka): [Queue Instrumentation 20] Log Kafka instrumentation failures #5315
• fix(kafka): [Queue Instrumentation 21] Preserve third-party baggage on Kafka producer records #5316
• test(spring-boot-jakarta): [Queue Instrumentation 22] Cover spring-kafka class-absence gate #5318

📜 Description

SentryKafkaProducerInterceptor.injectHeaders(...) previously removed and overwrote the outgoing baggage header on every record, discarding any third-party baggage entries already present on the ProducerRecord (e.g. set by another vendor's instrumentation or by the application itself).

injectHeaders(...) now reads the existing baggage header values off the record and passes them to TracingUtils.trace(scopes, existingBaggageHeaders, span). The downstream BaggageHeader.fromBaggageAndOutgoingHeader(...) parses those values, keeps the non-sentry-* entries, and appends them to Sentry's outgoing baggage — so upstream third-party baggage survives while Sentry still owns its own keys.

💡 Motivation and Context

Consistent with how sentry-okhttp, sentry-ktor-client, and the Spring HTTP interceptors already preserve third-party baggage by forwarding existing baggage header values into TracingUtils.traceIfAllowed(...). The raw Kafka producer integration should behave the same so customers don't lose vendor- or app-authored baggage entries when the Sentry producer interceptor writes its header.

💚 How did you test it?

• Added regression test preserves pre-existing third-party baggage header entries in SentryKafkaProducerInterceptorTest that pre-sets baggage: othervendor=someValue,another=thing on the record, runs onSend, and verifies the resulting outgoing baggage header contains both third-party entries and Sentry entries.
• ./gradlew :sentry-kafka:test --tests='io.sentry.kafka.SentryKafkaProducerInterceptorTest' — all 6 tests pass.
• ./gradlew spotlessApply apiDump — clean.

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

None.

⚠️ Merge this PR using a merge commit (not squash). Only the collection branch is squash-merged into main.

#skip-changelog