[sentry-junior]

📜 Description

Removes the traceSampling option for 9.0:

• SentryOptions.isTraceSampling() / setTraceSampling(boolean) and the backing field
• Android manifest key io.sentry.traces.trace-sampling (ManifestMetadataReader.TRACE_SAMPLING)
• The isTraceSampling() gates in SentryTracer and OtelSpanWrapper (traceContext() / toBaggageHeader()), TracingUtils.traceIfAllowed, and SentryApolloInterceptor
• Tests that only covered the option being disabled, plus isTraceSampling = true setup lines that matched the default

After this change:

• traceContext() and toBaggageHeader() return a value whenever the transaction has baggage.
• tracePropagationTargets is the only setting that controls outgoing sentry-trace/baggage headers.

💡 Motivation and Context

traceSampling has defaulted to true since 6.5.0-beta.2 (#2255). The getter is @ApiStatus.Experimental, the setter is @Deprecated in favor of tracePropagationTargets, and both Javadocs say "will be removed without notice". Even so, it still worked as a hidden switch for trace propagation in core, OpenTelemetry, Apollo and Android. Removing it leaves one supported way to control propagation.

Behavior change for anyone who set it to false:

• Outgoing HTTP: they can get the same result with an empty tracePropagationTargets. Apollo is the exception, because it calls TracingUtils.trace directly and has no URL to match against.
• Envelopes: there is no replacement for dropping the envelope trace header. Transactions with baggage always attach it now.

💚 How did you test it?

Ran locally on JDK 21:

• :sentry:test: TracingUtilsTest, SentryTracerTest, SpanTest, SentryClientTest
• :sentry-opentelemetry:sentry-opentelemetry-core:test
• :sentry-openfeign:test
• SentrySpanRest*CustomizerTest in sentry-spring-boot, sentry-spring-boot-jakarta and sentry-spring-boot-4
• :sentry-apollo:compileKotlin
• :sentry:apiDump, plus spotlessApply on the changed JVM modules

No Android SDK was available in the sandbox, so sentry-android-core (ManifestMetadataReader and its test) was not built locally. That change only deletes lines plus the now-unused ApiStatus import. CI should cover it.

📝 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.
• Public API changes reviewed by another Mobile SDK team member or implemented according to the develop docs spec.

🔮 Next steps

• Decide whether 9.0 needs a replacement switch for dropping the envelope trace header. I don't think it does, but I'd like a reviewer to confirm.
• Check whether hybrid SDKs (RN, Flutter, Unity, etc.) set traceSampling / io.sentry.traces.trace-sampling.
• Update the docs and the 9.0 migration guide where the option is mentioned.

via alexander.dinauer.

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View Junior Session [Sentry]

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.63.0 (1)	release

⚙️ sentry-android Build Distribution Settings

[romtsn]

LGTM! I agree we don't need a replacement switch for the trace header.

And one thing re. Apollo: theoretically, we could add Apollo span origins to ignoredSpanOrigins to stop creating headers, but it will also stop creating spans. Not sure if we should do it, but if we do, we need to add it to the migration guide.

[adinauer]

@romtsn we recently merged a community PR to add an extra flag for the integration, that allows opting out of the headers separately. I'll expand the changelog entry and migration guide.