feat(android): Report app start reason on standalone app start transaction by buenaflor · Pull Request #5552 · getsentry/sentry-java · GitHub

📜 Description

Reports why the OS started the process on the standalone app start transaction, using ApplicationStartInfo.getReason() (Android 15 / API 35+).

Adds AppStartMetrics.getAppStartReason(), which maps the already-cached ApplicationStartInfo reason to a stable lowercase string (launcher, launcher_recents, start_activity, broadcast, service, content_provider, job, alarm, push, backup, boot_complete, other). Returns null on API < 35, when no start info was resolved, or for an unmapped value.
Attaches it as app.vitals.start.reason trace data on the standalone app.start transaction in both paths: foreground/activity (onActivityCreated) and headless/non-activity (onHeadlessAppStart).
Also registers a StandaloneAppStart marker in the SDK metadata integrations when the feature is enabled (internal only, no changelog) so we can tell from events that standalone app start tracing was active.

Only standalone app start transactions are affected; this rides the existing enableStandaloneAppStartTracing opt-in and adds no new option.

💡 Motivation and Context

Builds on standalone app start tracing (#5342). The reason is a high-value dimension for standalone starts: it distinguishes a real user launch (launcher / start_activity) from headless starts (broadcast, service, content_provider, job, …) — exactly the disambiguation the headless app start path was built for. The reason (why the process started) is orthogonal to cold/warm (getStartType()), so both are reported.

ApplicationStartInfo is already cached in AppStartMetrics from the standalone work, so this only reads one additional field (getReason()) off the same object — no extra system calls.

💚 How did you test it?

Unit tests in sentry-android-core:

AppStartMetricsTestApi35: reason → string mapping (API 35), null when no start info, null for an unmapped reason value.
ActivityLifecycleIntegrationTest: app.vitals.start.reason present on the foreground standalone transaction (API 35), absent when unavailable, and present on the headless standalone transaction.

Note: the headless-vs-foreground detection in PerformanceAndroidEventProcessor keys off the absence of app.vitals.start.screen; the new distinct app.vitals.start.reason key does not affect it (existing tests still pass).

📝 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

Confirm with the product/spec side whether the reason should also be exposed as a queryable tag (in addition to span data), and lock in the exact string values dashboards/alerts will rely on.

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

Generated by 🚫 dangerJS against 2af9a1c

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.44.1 (1)	release

⚙️ sentry-android Build Distribution Settings

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	372.30 ms	460.98 ms	88.68 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
a416a65	316.52 ms	359.67 ms	43.15 ms
22ff2c7	306.60 ms	336.65 ms	30.05 ms
d15471f	310.26 ms	377.04 ms	66.78 ms
b750b96	408.98 ms	480.32 ms	71.34 ms
14ff5ee	419.75 ms	495.73 ms	75.98 ms
eb95ded	317.51 ms	369.08 ms	51.57 ms
c8125f3	383.82 ms	441.66 ms	57.84 ms
17a0955	372.53 ms	446.70 ms	74.17 ms
9d2f4e3	311.75 ms	357.80 ms	46.05 ms
ed33deb	343.30 ms	362.41 ms	19.10 ms

App size

Revision	Plain	With Sentry	Diff
a416a65	1.58 MiB	2.12 MiB	555.26 KiB
22ff2c7	0 B	0 B	0 B
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
b750b96	1.58 MiB	2.10 MiB	533.19 KiB
14ff5ee	1.58 MiB	2.10 MiB	535.08 KiB
eb95ded	0 B	0 B	0 B
c8125f3	1.58 MiB	2.10 MiB	532.32 KiB
17a0955	1.58 MiB	2.10 MiB	533.20 KiB
9d2f4e3	0 B	0 B	0 B
ed33deb	1.58 MiB	2.13 MiB	559.52 KiB

Previous results on branch: feat/android-app-start-reason

Startup times

Revision	Plain	With Sentry	Diff
3280187	343.87 ms	460.46 ms	116.59 ms
1b43bc2	317.36 ms	346.88 ms	29.52 ms

App size

Revision	Plain	With Sentry	Diff
3280187	0 B	0 B	0 B
1b43bc2	0 B	0 B	0 B

Pull request overview

Adds Android 15+ (API 35) enrichment to standalone app start tracing by attaching a stable, low-cardinality process start “reason” derived from ApplicationStartInfo.getReason() as trace data on the standalone app.start transaction.

Changes:

Add AppStartMetrics.getAppStartReason() to map ApplicationStartInfo start reasons to stable lowercase strings (or null when unavailable/unmapped).
Attach app.start.reason to the standalone app.start transaction for both foreground (onActivityCreated) and headless (onHeadlessAppStart) standalone paths.
Add/extend unit tests to cover mapping behavior and verify trace data presence/absence on standalone transactions.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
sentry-android-core/src/main/java/io/sentry/android/core/performance/AppStartMetrics.java	Adds getAppStartReason() mapping logic and a test-only setter for cached ApplicationStartInfo.
sentry-android-core/src/main/java/io/sentry/android/core/ActivityLifecycleIntegration.java	Writes app.start.reason trace data onto standalone app.start transactions in both foreground and headless flows.
sentry-android-core/src/test/java/io/sentry/android/core/performance/AppStartMetricsTestApi35.kt	Adds API 35 tests for reason→string mapping and null cases.
sentry-android-core/src/test/java/io/sentry/android/core/ActivityLifecycleIntegrationTest.kt	Adds tests asserting app.start.reason is present/absent on standalone transactions (foreground and headless).
sentry-android-core/api/sentry-android-core.api	Updates API dump for the new AppStartMetrics methods.
CHANGELOG.md	Documents the new app.start.reason data on API 35+ for standalone app start transactions.

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…ction Read ApplicationStartInfo.getReason() (API 35+) and attach it as app.start.reason trace data on the standalone app.start transaction in both the foreground and headless paths. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Advertise that standalone app start tracing is active by adding a StandaloneAppStart marker to the SDK metadata integrations when the feature is enabled. Internal SDK metadata only. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Looks great! I feel a bit mixed about the added ActivityLifecycleIntegrationTest.kt since we're just setting the value and then getting it.

dope!

I feel a bit mixed about the added ActivityLifecycleIntegrationTest.kt since we're just setting the value and then getting it.

Ah yeah, the mapping itself is covered in AppStartMetricsTestApi35, so these activity integration tests are really just checking the wiring that the reason ends up on the standalone app.start transaction under the right key, for both the foreground and headless paths

Address review feedback to mention that customers can search and group by the app.vitals.start.reason attribute. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

buenaflor force-pushed the feat/android-app-start-reason branch from d39e93a to 73d05fc Compare June 16, 2026 16:51

buenaflor marked this pull request as ready for review June 16, 2026 17:07

Copilot AI review requested due to automatic review settings June 16, 2026 17:07

buenaflor requested review from 0xadam-brown, adinauer, markushi, romtsn and runningcode as code owners June 16, 2026 17:07

Copilot started reviewing on behalf of buenaflor June 16, 2026 17:08 View session

Copilot AI reviewed Jun 16, 2026

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buenaflor force-pushed the feat/android-app-start-reason branch from 73d05fc to 2823497 Compare June 16, 2026 17:54

buenaflor force-pushed the feat/android-app-start-reason branch from 990e4c6 to 0b0dd48 Compare June 16, 2026 18:17

buenaflor commented Jun 16, 2026

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Comment thread sentry-android-core/src/main/java/io/sentry/android/core/ActivityLifecycleIntegration.java

runningcode approved these changes Jun 17, 2026

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romtsn reviewed Jun 17, 2026

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Comment thread CHANGELOG.md Outdated

romtsn approved these changes Jun 17, 2026

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docs(changelog): Note app.start.reason is searchable in Trace Explorer

2af9a1c

Address review feedback to mention that customers can search and group by the app.vitals.start.reason attribute. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

buenaflor merged commit 0c118e9 into main Jun 22, 2026
68 of 69 checks passed

buenaflor deleted the feat/android-app-start-reason branch June 22, 2026 09:02

feat(android): Report app start reason on standalone app start transaction by buenaflor · Pull Request #5552 · getsentry/sentry-java · GitHub

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feat(android): Report app start reason on standalone app start transaction - #5552

feat(android): Report app start reason on standalone app start transaction#5552
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feat(android): Report app start reason on standalone app start transaction by buenaflor · Pull Request #5552 · getsentry/sentry-java · GitHub

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feat(android): Report app start reason on standalone app start transaction - #5552

feat(android): Report app start reason on standalone app start transaction#5552buenaflor merged 3 commits intomaingetsentry/sentry-java:mainfrom feat/android-app-start-reasongetsentry/sentry-java:feat/android-app-start-reasonCopy head branch name to clipboard

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📜 Description

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

🔮 Next steps

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📲 Install Builds

Android

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Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

Previous results on branch: feat/android-app-start-reason

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