feat(android): [Session based Traces for Mobile 1B] Add session trace lifecycle

[adinauer]

PR Stack (Session based Traces for Mobile)

• feat(core): Session based Traces for Mobile #5383
• feat(android): [Session based Traces for Mobile 1B] Add session trace lifecycle #5398
• fix(core): [Session based Traces for Mobile 2] Keep transaction baggage mutable #5402

---

📜 Description

Adds opt-in Android session trace lifecycle support and simplifies the trace model by keeping session lifecycle behavior at the option/transaction level instead of storing lifecycle state on PropagationContext.

This PR:

• adds enableSessionTraceLifecycle configuration and Android wiring
• starts a new propagation context when Android starts a new session
• remaps eligible root transactions onto the current session trace
• preserves non-trace span/transaction context state while replacing only the trace id and clearing the parent span id
• keeps continued traces with a parent span out of session trace remapping
• removes the temporary propagation context lifecycle mode and forceNewTrace transaction flag

💡 Motivation and Context

Session-based traces on mobile need independently started root transactions to join the ambient app-session trace. Keeping this behavior behind an SDK option and deriving the opt-out from parentSpanId avoids per-context lifecycle state while preserving bounded/continued distributed traces.

This is the new first PR in the Session based Traces for Mobile stack: 1B.

💚 How did you test it?

• ./gradlew :sentry:compileJava :sentry:compileTestKotlin :sentry-opentelemetry:sentry-opentelemetry-core:compileJava
• ./gradlew :sentry:test --tests 'io.sentry.ScopesTest' --tests 'io.sentry.ScopeTest' --tests 'io.sentry.util.TracingUtilsTest' :sentry-opentelemetry:sentry-opentelemetry-core:test
• ./gradlew :sentry:test --tests 'io.sentry.ScopesTest.when session trace lifecycle is enabled, root transaction uses current propagation context' --tests 'io.sentry.ScopesTest.forceNewTrace does not override continued trace with parent span' spotlessApply apiDump
• ./gradlew :sentry:compileJava :sentry:compileTestKotlin
• ./gradlew :sentry:test --tests 'io.sentry.TransactionContextTest'
• ./gradlew :sentry:compileJava :sentry:compileTestKotlin :sentry:test --tests 'io.sentry.ScopesTest.continued trace with parent span is not remapped to session trace' --tests 'io.sentry.TransactionContextTest'
• ./gradlew spotlessApply apiDump

📝 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

Continue the Session based Traces for Mobile stack.

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

[github-actions]

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against 341ba6b

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.41.0 (1)	release

⚙️ sentry-android Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	316.96 ms	354.37 ms	37.41 ms
Size	0 B	0 B	0 B

Previous results on branch: ref/remove-propagation-context-mode

Startup times

Revision	Plain	With Sentry	Diff
f15a0c5	321.71 ms	365.46 ms	43.75 ms
c183fb7	368.02 ms	436.96 ms	68.94 ms

App size

Revision	Plain	With Sentry	Diff
f15a0c5	0 B	0 B	0 B
c183fb7	0 B	0 B	0 B