feat(tracing): Add standalone app start transaction by antonis · Pull Request #6359 · getsentry/sentry-react-native

antonis · 2026-06-26T11:13:33Z

📢 Type of change

Bugfix
New feature
Enhancement
Refactoring

📜 Description

Adds an experimental, opt-in flag _experiments.enableStandaloneAppStartTracing that sends app start as a dedicated app.start transaction instead of attaching app start data to the first navigation (ui.load) transaction.

💡 Motivation and Context

Closes #5839.

💚 How did you test it?

Unit tests in appStart.test.ts migrated to the V2 encoding (op app.start, vitals attributes, no legacy span/measurement); breakdown-span, frame-data, and appLoaded() standalone tests updated accordingly.
New trace-connection test: the app.start transaction shares trace_id with the navigation transaction.
New defaultAppStart.test.ts: verifies the flag wires standalone on/off/default.
Added hermetic snapshot tests that byte-lock the full event for both flows. The default (non-opt-in) snapshot was generated against the pre-change SDK and matches unchanged after the change — proving the default path is byte-identical; the standalone snapshot guards the Span V2 encoding.
Added a regression test for the standalone age-check fix (slow device: app start timestamp older than MAX_APP_START_AGE_MS is still sent), with the non-standalone path still asserting the age check applies.
Added regression tests for the duplicate-transaction fixes: (a) deferred auto-capture fires, then appLoaded() arrives, and (b) appLoaded() races an in-flight deferred capture → in both cases only one app.start transaction is sent; verified each fails before the fix (2 transactions) and passes after.
Full suite green. Build, API report, lint, and circular-dep checks all pass.

📝 Checklist

I added tests to verify 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.
All tests passing
No breaking changes

🔮 Next steps

linear-code · 2026-06-26T11:13:43Z

RN-541

github-actions · 2026-06-26T11:13:53Z

Semver Impact of This PR

⚪ None (no version bump detected)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

feat(tracing): Add standalone app start transaction by antonis in #6359

chore(deps): update Cocoa SDK to v9.19.1 by github-actions in #6389
chore: Add PR template checkbox for cross sdk review on public API changes by antonis in #6386
fix(e2e): Remove dead OSSRH snapshots repo from RN 0.71 Gradle plugin by antonis in #6387
chore(deps): update JavaScript SDK to v10.63.0 by github-actions in #6388
chore(e2e): Update Expo sample to SDK 57 by antonis in #6385
chore: Auto-request mobile team review on public API changes by antonis in #6383
fix(replay): Forward Session Replay network detail options to native SDKs by antonis in #6373
fix(ci): Pin Android E2E emulator to build 15679343 (37.1.5.0) by antonis in #6378
feat(core): Expose top-level Sentry.setAttribute / setAttributes by antonis in #6354
docs: Add AI Use section to CONTRIBUTING.md by christophaigner in #6374
feat(replay): Default networkCaptureBodies to true by alwx in #6372
chore(deps): bump getsentry/craft from 2.26.10 to 2.26.13 by dependabot in #6368
chore(deps): bump getsentry/github-workflows/danger from 17cc15eb58ea3687cd8f2714a4192dcee4aa09ef to 4013fc6e1aeb1be1f9d3b4d232624f0ec1afa613 by dependabot in #6366
chore(deps): bump getsentry/github-workflows/validate-pr from 71588ddf95134f804e82c5970a8098588e2eaecd to 4013fc6e1aeb1be1f9d3b4d232624f0ec1afa613 by dependabot in #6364
chore(deps): bump getsentry/craft/.github/workflows/changelog-preview.yml from 2.26.10 to 2.26.13 by dependabot in #6367
feat(core): Wire TurboModulePerfLogger on iOS and Android by alwx in #6307
chore(deps): bump actions/cache from 4 to 6 by dependabot in #6365
chore(deps): update CLI to v3.6.0 by github-actions in #6362
chore(deps): bump faraday from 1.10.5 to 1.10.6 in /samples/react-native by dependabot in #6363
chore(deps): update JavaScript SDK to v10.62.0 by github-actions in #6361
Expo Router ErrorBoundary auto wrapped by alwx in #6347
chore(ci): Move sample app iOS build jobs to GitHub Actions runners by itaybre in #6356
docs: Add missing 8.14.1 to changelog and SDK versions table by antonis in #6360

Plus 3 more

_{🤖 This preview updates automatically when you update the PR.}

github-actions · 2026-06-26T11:14:11Z

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

Generated by 🚫 dangerJS against 94e5885

cursor

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit d5b4af2. Configure here.}

The MAX_APP_START_AGE_MS bounds check compared the native app start time against `event.start_timestamp`, which for a standalone transaction still holds the span creation time at that point (it is corrected to the native app start time later). On slow devices that gap can exceed the threshold and discard a valid app start. The age check only makes sense for the non-standalone path (where app start is attached to a later navigation transaction), so skip it for standalone; the duration check still filters genuinely bogus app starts. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

In standalone mode the deferred auto-capture (`setTimeout(0)`) is meant to be cancelled by a later `appLoaded()` call. But once the deferred send has fired, `cancelDeferredStandaloneCapture()` is a no-op and `_appLoaded()` reset the flushed flag and sent a second `app.start` transaction for the same app run (the common case, since apps signal readiness in a later macrotask). Track whether a standalone transaction has already been sent and skip re-sending; reset the flag on `runApplication` so a new app run can send again. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

…ture `captureStandaloneAppStart` awaits native work before it marks the transaction as sent, so a late `appLoaded()` racing an in-flight deferred capture could pass the sent-guard and emit a second `app.start` transaction. Add an in-flight flag set synchronously at entry (no await before it, so the check-and-set is atomic in JS) and cleared in a `finally`, alongside the existing already-sent guard. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

cursor

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit cafa472. Configure here.}

Add experimental `_experiments.enableStandaloneAppStartTracing` to send app start as a dedicated `app.start` transaction (Span V2) instead of attaching app start data to the first navigation (`ui.load`) transaction. The standalone transaction uses op `app.start`, name `App Start`, and carries the vitals as attributes on the root span (`app.vitals.start.value`, `app.vitals.start.type`). This decouples app start from the navigation transaction lifecycle, so it is no longer lost when no qualifying navigation transaction is sent. The legacy (non-standalone) path is unchanged and remains the default. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Add hermetic snapshot tests that byte-lock the full event for both the default (non-standalone) and opt-in standalone cold app start flows. The default snapshot was generated against the pre-change SDK and matches unchanged after the standalone changes, proving the non-opt-in path is unaffected. The standalone snapshot guards the Span V2 encoding (op `app.start`, `app.vitals.start.*`, no legacy per-type span/measurement). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

The MAX_APP_START_AGE_MS bounds check compared the native app start time against `event.start_timestamp`, which for a standalone transaction still holds the span creation time at that point (it is corrected to the native app start time later). On slow devices that gap can exceed the threshold and discard a valid app start. The age check only makes sense for the non-standalone path (where app start is attached to a later navigation transaction), so skip it for standalone; the duration check still filters genuinely bogus app starts. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

In standalone mode the deferred auto-capture (`setTimeout(0)`) is meant to be cancelled by a later `appLoaded()` call. But once the deferred send has fired, `cancelDeferredStandaloneCapture()` is a no-op and `_appLoaded()` reset the flushed flag and sent a second `app.start` transaction for the same app run (the common case, since apps signal readiness in a later macrotask). Track whether a standalone transaction has already been sent and skip re-sending; reset the flag on `runApplication` so a new app run can send again. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

…ture `captureStandaloneAppStart` awaits native work before it marks the transaction as sent, so a late `appLoaded()` racing an in-flight deferred capture could pass the sent-guard and emit a second `app.start` transaction. Add an in-flight flag set synchronously at entry (no await before it, so the check-and-set is atomic in JS) and cleared in a `finally`, alongside the existing already-sent guard. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

- Trim the synthetic breakdown-parent to the fields the span helpers actually read (op/origin/span_id/trace_id/start_timestamp/data); drop the inert ones. - Gate the carrier-transaction end-timestamp clamp to non-standalone, since the standalone path sets its end timestamp explicitly. No behavior change — the default and standalone event snapshots are unchanged. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

sentry · 2026-06-26T13:42:08Z

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
Sentry RN	io.sentry.reactnative.sample	8.16.0 (94)	Release

⚙️ sentry-react-native Build Distribution Settings

github-actions · 2026-06-26T13:51:13Z

iOS (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	3850.15 ms	1216.50 ms	-2633.65 ms
Size	4.98 MiB	6.51 MiB	1.53 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`a50b33d`+dirty	1197.74 ms	1197.17 ms	-0.57 ms
`0d9949d`+dirty	1211.38 ms	1219.67 ms	8.29 ms
`5ee78d6`+dirty	3847.52 ms	1224.27 ms	-2623.25 ms
`100ce80`+dirty	3842.93 ms	1229.52 ms	-2613.41 ms
`6176a94`+dirty	3836.50 ms	1217.64 ms	-2618.86 ms
`bc0d8cf`+dirty	3830.33 ms	1220.52 ms	-2609.81 ms
`5fe1c6c`+dirty	1220.79 ms	1217.63 ms	-3.16 ms
`37a2091`+dirty	3821.77 ms	1212.34 ms	-2609.43 ms
`4e0ba9c`+dirty	3839.22 ms	1221.06 ms	-2618.16 ms
`5a23c47`+dirty	3855.46 ms	1221.95 ms	-2633.50 ms

App size

Revision	Plain	With Sentry	Diff
`a50b33d`+dirty	3.38 MiB	4.73 MiB	1.35 MiB
`0d9949d`+dirty	3.38 MiB	4.76 MiB	1.38 MiB
`5ee78d6`+dirty	5.15 MiB	6.69 MiB	1.53 MiB
`100ce80`+dirty	5.15 MiB	6.67 MiB	1.51 MiB
`6176a94`+dirty	5.15 MiB	6.68 MiB	1.53 MiB
`bc0d8cf`+dirty	5.15 MiB	6.67 MiB	1.51 MiB
`5fe1c6c`+dirty	3.38 MiB	4.77 MiB	1.39 MiB
`37a2091`+dirty	5.15 MiB	6.70 MiB	1.54 MiB
`4e0ba9c`+dirty	5.15 MiB	6.67 MiB	1.51 MiB
`5a23c47`+dirty	4.98 MiB	6.46 MiB	1.49 MiB

Previous results on branch: antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation

Startup times

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	3832.21 ms	1216.71 ms	-2615.50 ms

App size

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	4.98 MiB	6.51 MiB	1.53 MiB

github-actions · 2026-06-26T13:58:54Z

Android (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	440.78 ms	446.15 ms	5.36 ms
Size	49.74 MiB	55.09 MiB	5.34 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`a858ac3`+dirty	426.50 ms	484.82 ms	58.32 ms
`4e0ba9c`+dirty	452.84 ms	473.36 ms	20.52 ms
`0a147b2`+dirty	464.71 ms	538.81 ms	74.09 ms
`9474ead`+dirty	411.45 ms	446.80 ms	35.35 ms
`7887847`+dirty	416.61 ms	462.04 ms	45.43 ms
`5a21b51`+dirty	471.42 ms	524.22 ms	52.80 ms
`4966363`+dirty	400.04 ms	431.08 ms	31.04 ms
`1a2e7e0`+dirty	416.61 ms	445.46 ms	28.85 ms
`f170ec3`+dirty	428.71 ms	452.18 ms	23.47 ms
`a50b33d`+dirty	500.81 ms	532.11 ms	31.30 ms

App size

Revision	Plain	With Sentry	Diff
`a858ac3`+dirty	49.74 MiB	55.08 MiB	5.34 MiB
`4e0ba9c`+dirty	48.30 MiB	53.49 MiB	5.19 MiB
`0a147b2`+dirty	49.74 MiB	55.08 MiB	5.34 MiB
`9474ead`+dirty	48.30 MiB	53.61 MiB	5.30 MiB
`7887847`+dirty	49.74 MiB	54.81 MiB	5.07 MiB
`5a21b51`+dirty	48.30 MiB	53.49 MiB	5.19 MiB
`4966363`+dirty	48.30 MiB	53.54 MiB	5.24 MiB
`1a2e7e0`+dirty	49.74 MiB	54.82 MiB	5.07 MiB
`f170ec3`+dirty	48.30 MiB	53.57 MiB	5.26 MiB
`a50b33d`+dirty	43.75 MiB	48.08 MiB	4.33 MiB

Previous results on branch: antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation

Startup times

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	465.54 ms	549.85 ms	84.31 ms

App size

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	49.74 MiB	54.85 MiB	5.11 MiB

github-actions · 2026-06-26T14:33:53Z

iOS (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	3845.11 ms	1229.57 ms	-2615.54 ms
Size	4.98 MiB	6.51 MiB	1.53 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`267d3ed`+dirty	3860.14 ms	1223.39 ms	-2636.76 ms
`a5d243c`+dirty	3827.92 ms	1220.10 ms	-2607.81 ms
`5c1e987`+dirty	1208.43 ms	1220.72 ms	12.29 ms
`b9bebee`+dirty	3858.02 ms	1231.92 ms	-2626.11 ms
`853723c`+dirty	3849.33 ms	1221.07 ms	-2628.26 ms
`c151573`+dirty	3835.64 ms	1216.10 ms	-2619.53 ms
`1a2e7e0`+dirty	3852.95 ms	1233.78 ms	-2619.18 ms
`7d6fd3a`+dirty	1210.89 ms	1217.63 ms	6.74 ms
`a3265b6`+dirty	3844.26 ms	1235.60 ms	-2608.66 ms
`df5d108`+dirty	1207.34 ms	1210.50 ms	3.16 ms

App size

Revision	Plain	With Sentry	Diff
`267d3ed`+dirty	5.15 MiB	6.69 MiB	1.54 MiB
`a5d243c`+dirty	5.15 MiB	6.68 MiB	1.53 MiB
`5c1e987`+dirty	3.38 MiB	4.73 MiB	1.35 MiB
`b9bebee`+dirty	5.15 MiB	6.68 MiB	1.53 MiB
`853723c`+dirty	5.15 MiB	6.69 MiB	1.53 MiB
`c151573`+dirty	5.15 MiB	6.68 MiB	1.53 MiB
`1a2e7e0`+dirty	4.98 MiB	6.46 MiB	1.49 MiB
`7d6fd3a`+dirty	3.38 MiB	4.77 MiB	1.39 MiB
`a3265b6`+dirty	5.15 MiB	6.68 MiB	1.53 MiB
`df5d108`+dirty	3.38 MiB	4.73 MiB	1.35 MiB

Previous results on branch: antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation

Startup times

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	3838.67 ms	1213.69 ms	-2624.98 ms

App size

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	4.98 MiB	6.50 MiB	1.52 MiB

github-actions · 2026-06-26T14:48:07Z

Android (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	407.36 ms	441.70 ms	34.34 ms
Size	49.74 MiB	55.08 MiB	5.34 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`3d377b5`+dirty	425.38 ms	440.67 ms	15.30 ms
`a3265b6`+dirty	410.96 ms	444.76 ms	33.80 ms
`20fbd51`+dirty	594.38 ms	655.35 ms	60.97 ms
`5ee78d6`+dirty	411.18 ms	437.83 ms	26.65 ms
`7a89652`+dirty	405.00 ms	437.04 ms	32.04 ms
`09a902f`+dirty	423.02 ms	472.18 ms	49.16 ms
`68ae91b`+dirty	515.04 ms	578.08 ms	63.04 ms
`0d9949d`+dirty	414.88 ms	428.68 ms	13.81 ms
`4b87b12`+dirty	356.23 ms	399.86 ms	43.63 ms
`71abba0`+dirty	411.04 ms	453.67 ms	42.63 ms

App size

Revision	Plain	With Sentry	Diff
`3d377b5`+dirty	43.94 MiB	49.00 MiB	5.06 MiB
`a3265b6`+dirty	48.30 MiB	53.58 MiB	5.28 MiB
`20fbd51`+dirty	49.74 MiB	54.81 MiB	5.07 MiB
`5ee78d6`+dirty	48.30 MiB	53.58 MiB	5.28 MiB
`7a89652`+dirty	48.30 MiB	53.60 MiB	5.30 MiB
`09a902f`+dirty	49.74 MiB	54.81 MiB	5.07 MiB
`68ae91b`+dirty	49.74 MiB	54.79 MiB	5.05 MiB
`0d9949d`+dirty	43.94 MiB	48.99 MiB	5.05 MiB
`4b87b12`+dirty	43.94 MiB	49.00 MiB	5.06 MiB
`71abba0`+dirty	48.30 MiB	53.49 MiB	5.19 MiB

Previous results on branch: antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation

Startup times

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	418.21 ms	464.18 ms	45.97 ms

App size

Revision	Plain	With Sentry	Diff
`bc395fb`+dirty	49.74 MiB	54.85 MiB	5.11 MiB

Replace the `standaloneAppStartSent` + `standaloneCaptureInProgress` pair (and the try/finally) with a single `standaloneAppStartCaptured` flag, set synchronously at the start of `captureStandaloneAppStart` before any await. Being set atomically makes it both the once-per-run guard and the in-flight guard, so a late or racing trigger for the same run bails cleanly. It is reset on runApplication so the next app run captures again. Also remove the now-vestigial `resetAppStartDataFlushed()`: appLoaded() overrides the end timestamp by cancelling the deferred send before it fires; once the deferred has fired the transaction is already sent, so re-sending would duplicate. The reset call only tried (and failed) to enable that duplicate send. Cross-run dedup continues to rely on the native `has_fetched` flag. Addresses review findings on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

…-start-data-from-navigation

antonis · 2026-06-29T08:09:19Z

@sentry review

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 1e78698. Configure here.}

…-start-data-from-navigation

…eattracing-decouple-app-start-data-from-navigation

lucas-zimerman

LGTM!

…-start-data-from-navigation

…6369) * feat(tracing): Add standalone app start transaction (RN-541) Add experimental `_experiments.enableStandaloneAppStartTracing` to send app start as a dedicated `app.start` transaction (Span V2) instead of attaching app start data to the first navigation (`ui.load`) transaction. The standalone transaction uses op `app.start`, name `App Start`, and carries the vitals as attributes on the root span (`app.vitals.start.value`, `app.vitals.start.type`). This decouples app start from the navigation transaction lifecycle, so it is no longer lost when no qualifying navigation transaction is sent. The legacy (non-standalone) path is unchanged and remains the default. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * docs: Link PR in changelog entry Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * test(tracing): Lock app start event shape with snapshots Add hermetic snapshot tests that byte-lock the full event for both the default (non-standalone) and opt-in standalone cold app start flows. The default snapshot was generated against the pre-change SDK and matches unchanged after the standalone changes, proving the non-opt-in path is unaffected. The standalone snapshot guards the Span V2 encoding (op `app.start`, `app.vitals.start.*`, no legacy per-type span/measurement). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * fix(tracing): Skip app start age check for standalone transactions The MAX_APP_START_AGE_MS bounds check compared the native app start time against `event.start_timestamp`, which for a standalone transaction still holds the span creation time at that point (it is corrected to the native app start time later). On slow devices that gap can exceed the threshold and discard a valid app start. The age check only makes sense for the non-standalone path (where app start is attached to a later navigation transaction), so skip it for standalone; the duration check still filters genuinely bogus app starts. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * fix(tracing): Prevent duplicate standalone app start transactions In standalone mode the deferred auto-capture (`setTimeout(0)`) is meant to be cancelled by a later `appLoaded()` call. But once the deferred send has fired, `cancelDeferredStandaloneCapture()` is a no-op and `_appLoaded()` reset the flushed flag and sent a second `app.start` transaction for the same app run (the common case, since apps signal readiness in a later macrotask). Track whether a standalone transaction has already been sent and skip re-sending; reset the flag on `runApplication` so a new app run can send again. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * fix(tracing): Guard against racing in-flight standalone app start capture `captureStandaloneAppStart` awaits native work before it marks the transaction as sent, so a late `appLoaded()` racing an in-flight deferred capture could pass the sent-guard and emit a second `app.start` transaction. Add an in-flight flag set synchronously at entry (no await before it, so the check-and-set is atomic in JS) and cleared in a `finally`, alongside the existing already-sent guard. Surfaced by automated review on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * refactor(tracing): Tidy standalone app start implementation - Trim the synthetic breakdown-parent to the fields the span helpers actually read (op/origin/span_id/trace_id/start_timestamp/data); drop the inert ones. - Gate the carrier-transaction end-timestamp clamp to non-standalone, since the standalone path sets its end timestamp explicitly. No behavior change — the default and standalone event snapshots are unchanged. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * refactor(tracing): Simplify standalone app start dedup to a single guard Replace the `standaloneAppStartSent` + `standaloneCaptureInProgress` pair (and the try/finally) with a single `standaloneAppStartCaptured` flag, set synchronously at the start of `captureStandaloneAppStart` before any await. Being set atomically makes it both the once-per-run guard and the in-flight guard, so a late or racing trigger for the same run bails cleanly. It is reset on runApplication so the next app run captures again. Also remove the now-vestigial `resetAppStartDataFlushed()`: appLoaded() overrides the end timestamp by cancelling the deferred send before it fires; once the deferred has fired the transaction is already sent, so re-sending would duplicate. The reset call only tried (and failed) to enable that duplicate send. Cross-run dedup continues to rely on the native `has_fetched` flag. Addresses review findings on #6359. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * feat(tracing): Emit app.vitals.start.screen on standalone app start (RN-691) Set the `app.vitals.start.screen` attribute on the standalone `app.start` transaction from the current route tracked by the tracing integration. Unlike the non-standalone `ui.load` transaction (named after the screen, which Relay backfills from), the standalone transaction is named `App Start`, so the screen is set explicitly. Omitted when no route has been registered yet at capture time. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> * docs: Add changelog entry for app.vitals.start.screen Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

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Comment thread packages/core/src/js/tracing/integrations/appStart.ts

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antonis and others added 7 commits June 26, 2026 15:19

docs: Link PR in changelog entry

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Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

antonis force-pushed the antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation branch from cafa472 to 3ddd44c Compare June 26, 2026 13:26

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feat(tracing): Emit app.vitals.start.screen on standalone app start #6369

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antonis requested a review from lucas-zimerman June 30, 2026 12:40

yonitou mentioned this pull request Jun 30, 2026

Android: app_start_cold is inflated when the process is background-spawned (FCM) before the user opens the app #6382

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antonis merged commit 40c9884 into main Jul 2, 2026
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antonis deleted the antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation branch July 2, 2026 08:45

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feat(tracing): Add extend app start API for standalone app start #6392

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publish: getsentry/sentry-react-native@8.17.0 getsentry/publish#8775

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feat(tracing): Decouple app start data from navigation transaction lifecycle #5839

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📢 Type of change

📜 Description

💡 Motivation and Context

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📝 Checklist

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iOS (legacy) Performance metrics 🚀

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Android (legacy) Performance metrics 🚀

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Previous results on branch: antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation

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App size

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iOS (new) Performance metrics 🚀

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Previous results on branch: antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation

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App size

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Android (new) Performance metrics 🚀

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Previous results on branch: antonislilis/rn-541-feattracing-decouple-app-start-data-from-navigation

Startup times

App size

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