fix(tracing): Keep launch-screen TTID/TTFD anchored to navigation on delayed first navigation - #6626
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Semver Impact of This PR⚪ None (no version bump detected) 📋 Changelog PreviewThis is how your changes will appear in the changelog.
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…delayed first navigation For non-standalone app start tracking, attaching app start to the first navigation transaction re-anchored its start_timestamp to process init, which made auto time_to_initial_display/time_to_full_display absorb the uninstrumented gap before a delayed first navigation (splash / auth / loading). The later 30s TTID/TTFD cap then right-censored this into a large plateau. When the gap between app start end and the first navigation start exceeds 5s, report the app_start_cold/app_start_warm measurement but leave the screen TTID/TTFD anchored to the navigation start, so they measure the actual screen render. Genuine cold-start displays (first navigation follows app start promptly) keep the existing app-start-anchored behavior unchanged. Fixes #6618 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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iOS (legacy) Performance metrics 🚀
|
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| ecf47a2+dirty | 3835.20 ms | 1222.43 ms | -2612.77 ms |
| 3817909+dirty | 1183.90 ms | 1187.50 ms | 3.60 ms |
| 5ee78d6+dirty | 3847.52 ms | 1224.27 ms | -2623.25 ms |
| 890d145+dirty | 1223.59 ms | 1231.37 ms | 7.78 ms |
| e763471+dirty | 3841.16 ms | 1218.06 ms | -2623.09 ms |
| 3d31fcf+dirty | 3838.09 ms | 1223.46 ms | -2614.63 ms |
| 9210ae6+dirty | 3815.93 ms | 1214.14 ms | -2601.79 ms |
| 26843eb+dirty | 3861.60 ms | 1238.77 ms | -2622.82 ms |
| 7a89652+dirty | 3861.46 ms | 1229.61 ms | -2631.85 ms |
| 9ad4522+dirty | 3850.40 ms | 1222.40 ms | -2628.00 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| ecf47a2+dirty | 4.98 MiB | 6.46 MiB | 1.49 MiB |
| 3817909+dirty | 3.38 MiB | 4.73 MiB | 1.35 MiB |
| 5ee78d6+dirty | 5.15 MiB | 6.69 MiB | 1.53 MiB |
| 890d145+dirty | 3.38 MiB | 4.77 MiB | 1.38 MiB |
| e763471+dirty | 4.98 MiB | 6.51 MiB | 1.53 MiB |
| 3d31fcf+dirty | 4.98 MiB | 6.56 MiB | 1.58 MiB |
| 9210ae6+dirty | 5.15 MiB | 6.68 MiB | 1.53 MiB |
| 26843eb+dirty | 4.98 MiB | 6.53 MiB | 1.55 MiB |
| 7a89652+dirty | 5.15 MiB | 6.70 MiB | 1.55 MiB |
| 9ad4522+dirty | 4.98 MiB | 6.56 MiB | 1.58 MiB |
Previous results on branch: fix/launch-screen-ttid-delayed-navigation
Startup times
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 3830.98 ms | 1209.45 ms | -2621.53 ms |
| aa36375+dirty | 3840.60 ms | 1223.73 ms | -2616.87 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 5.08 MiB | 6.80 MiB | 1.72 MiB |
| aa36375+dirty | 5.08 MiB | 6.72 MiB | 1.64 MiB |
Contributor
Android (new) Performance metrics 🚀
|
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 15d4514+dirty | 413.63 ms | 449.62 ms | 35.99 ms |
| 26843eb+dirty | 442.02 ms | 506.29 ms | 64.27 ms |
| ca9d079+dirty | 460.67 ms | 512.54 ms | 51.87 ms |
| f9c1ed4+dirty | 520.57 ms | 594.84 ms | 74.27 ms |
| a0d8cf8+dirty | 533.71 ms | 564.25 ms | 30.54 ms |
| 20fbd51+dirty | 594.38 ms | 655.35 ms | 60.97 ms |
| 0b0f006+dirty | 446.31 ms | 458.31 ms | 12.00 ms |
| 1d3572b+dirty | 444.48 ms | 478.42 ms | 33.94 ms |
| 4953e94+dirty | 398.80 ms | 431.81 ms | 33.01 ms |
| 4e0b819+dirty | 599.31 ms | 654.31 ms | 55.00 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 15d4514+dirty | 48.30 MiB | 53.60 MiB | 5.30 MiB |
| 26843eb+dirty | 49.74 MiB | 55.26 MiB | 5.52 MiB |
| ca9d079+dirty | 48.30 MiB | 53.58 MiB | 5.28 MiB |
| f9c1ed4+dirty | 49.74 MiB | 54.86 MiB | 5.12 MiB |
| a0d8cf8+dirty | 48.30 MiB | 53.49 MiB | 5.19 MiB |
| 20fbd51+dirty | 49.74 MiB | 54.81 MiB | 5.07 MiB |
| 0b0f006+dirty | 49.74 MiB | 55.66 MiB | 5.91 MiB |
| 1d3572b+dirty | 49.74 MiB | 55.38 MiB | 5.63 MiB |
| 4953e94+dirty | 43.94 MiB | 48.94 MiB | 5.00 MiB |
| 4e0b819+dirty | 49.74 MiB | 54.81 MiB | 5.07 MiB |
Previous results on branch: fix/launch-screen-ttid-delayed-navigation
Startup times
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 654.79 ms | 700.42 ms | 45.63 ms |
| aa36375+dirty | 422.38 ms | 446.45 ms | 24.07 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 49.74 MiB | 55.66 MiB | 5.91 MiB |
| aa36375+dirty | 49.74 MiB | 55.45 MiB | 5.71 MiB |
Contributor
iOS (new) Performance metrics 🚀
|
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 3b6e9f9+dirty | 3822.77 ms | 1208.00 ms | -2614.77 ms |
| 5a23c47+dirty | 3843.54 ms | 1226.05 ms | -2617.50 ms |
| 100ce80+dirty | 3843.57 ms | 1226.46 ms | -2617.12 ms |
| 0bd8916+dirty | 3816.17 ms | 1215.05 ms | -2601.12 ms |
| a0d8cf8+dirty | 3826.15 ms | 1213.12 ms | -2613.03 ms |
| 0a9e622+dirty | 3825.35 ms | 1219.04 ms | -2606.31 ms |
| 21a1e70+dirty | 3826.22 ms | 1217.74 ms | -2608.47 ms |
| 9ad4522+dirty | 3862.28 ms | 1226.27 ms | -2636.01 ms |
| 88735e9+dirty | 3837.80 ms | 1216.39 ms | -2621.41 ms |
| d0e3b3e+dirty | 3846.64 ms | 1226.27 ms | -2620.38 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 3b6e9f9+dirty | 5.15 MiB | 6.68 MiB | 1.53 MiB |
| 5a23c47+dirty | 4.98 MiB | 6.46 MiB | 1.49 MiB |
| 100ce80+dirty | 5.15 MiB | 6.67 MiB | 1.51 MiB |
| 0bd8916+dirty | 5.15 MiB | 6.69 MiB | 1.53 MiB |
| a0d8cf8+dirty | 5.15 MiB | 6.67 MiB | 1.51 MiB |
| 0a9e622+dirty | 4.98 MiB | 6.51 MiB | 1.53 MiB |
| 21a1e70+dirty | 4.98 MiB | 6.46 MiB | 1.49 MiB |
| 9ad4522+dirty | 4.98 MiB | 6.56 MiB | 1.58 MiB |
| 88735e9+dirty | 4.98 MiB | 6.46 MiB | 1.49 MiB |
| d0e3b3e+dirty | 4.98 MiB | 6.51 MiB | 1.53 MiB |
Previous results on branch: fix/launch-screen-ttid-delayed-navigation
Startup times
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 3840.21 ms | 1220.13 ms | -2620.09 ms |
| aa36375+dirty | 3848.71 ms | 1213.00 ms | -2635.71 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 5.08 MiB | 6.80 MiB | 1.72 MiB |
| aa36375+dirty | 5.08 MiB | 6.72 MiB | 1.64 MiB |
Contributor
Android (legacy) Performance metrics 🚀
|
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| f9c1ed4+dirty | 431.00 ms | 466.22 ms | 35.22 ms |
| c2e182c+dirty | 471.64 ms | 553.59 ms | 81.95 ms |
| 41d6254+dirty | 424.45 ms | 474.34 ms | 49.89 ms |
| af33f3b+dirty | 434.90 ms | 506.14 ms | 71.24 ms |
| 882f8ae+dirty | 399.98 ms | 427.06 ms | 27.08 ms |
| 0b5120f+dirty | 503.22 ms | 538.60 ms | 35.38 ms |
| 774257e+dirty | 407.09 ms | 447.46 ms | 40.37 ms |
| bf168a4+dirty | 418.21 ms | 489.74 ms | 71.53 ms |
| 5569641+dirty | 406.43 ms | 428.51 ms | 22.08 ms |
| c151573+dirty | 530.34 ms | 559.43 ms | 29.09 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| f9c1ed4+dirty | 49.74 MiB | 54.86 MiB | 5.12 MiB |
| c2e182c+dirty | 49.74 MiB | 54.85 MiB | 5.11 MiB |
| 41d6254+dirty | 48.30 MiB | 53.60 MiB | 5.30 MiB |
| af33f3b+dirty | 49.74 MiB | 55.09 MiB | 5.35 MiB |
| 882f8ae+dirty | 48.30 MiB | 53.60 MiB | 5.29 MiB |
| 0b5120f+dirty | 48.30 MiB | 53.58 MiB | 5.28 MiB |
| 774257e+dirty | 48.30 MiB | 53.58 MiB | 5.28 MiB |
| bf168a4+dirty | 49.74 MiB | 55.09 MiB | 5.35 MiB |
| 5569641+dirty | 48.30 MiB | 53.48 MiB | 5.18 MiB |
| c151573+dirty | 48.30 MiB | 53.54 MiB | 5.24 MiB |
Previous results on branch: fix/launch-screen-ttid-delayed-navigation
Startup times
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 477.43 ms | 508.29 ms | 30.86 ms |
| aa36375+dirty | 415.10 ms | 429.02 ms | 13.92 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 23b101e+dirty | 49.74 MiB | 55.66 MiB | 5.91 MiB |
| aa36375+dirty | 49.74 MiB | 55.45 MiB | 5.71 MiB |
antonis
marked this pull request as ready for review
August 27, 2026 14:29
Co-authored-by: LucasZF <lucas-zimerman1@hotmail.com>
antonis
enabled auto-merge (squash)
September 2, 2026 06:46
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📢 Type of change
📜 Description
On non-standalone app start tracking, attaching app start to the first navigation transaction rewrites its
start_timestampto process init and re-anchors the TTID/TTFD spans to it;timeToDisplay(which runs after) then derivestime_to_initial_display/time_to_full_displayfrom that rewritten start.On a delayed first navigation — a splash / auth / loading screen held for several seconds — this makes TTID/TTFD span the uninstrumented app-ready → navigation gap instead of the screen render, inflating them by an order of magnitude (e.g. ~0.9s → ~23s in #6618; the 30s cap from #6210 flattens the overflow into a plateau).
This adds a gap check: when
first navigation start − app start end > 5s, the SDK still reports theapp_start_cold/app_start_warmmeasurement but leavesstart_timestamp(and therefore TTID/TTFD) at the navigation start, so they measure the real render. Prompt cold-start displays (gap ≤ 5s) are unchanged. Scoped to non-standalone, non-__DEV__, and runs after the existing age/duration guards.The
5scutoff is a heuristic; a root-cause fix would use a native initial-display signal instead of elapsed time (see Next steps).💡 Motivation and Context
React Native decouples JS navigation from native app start, so the first
navigationtransaction can fire arbitrarily late. The TTID/TTFD spec anchors first-screen TTID to app start with no gap guard, because on native the first Activity is the app start — they can't be seconds apart. On RN they can, producing a gap the spec never contemplated.Fixes #6618
💚 How did you test it?
appStart.test.ts: delayed nav keepsstart_timestampat the navigation start and adds noCold Start/Warm Startspan while still reportingapp_start_cold/warm; prompt nav (< 5s) keeps the existing app-start-anchored behavior; dev build skips the branch.appStart.test.ts(94 passing, incl. snapshots) andtimeToDisplayIntegration.test.tspass;yarn build, TS/JS lint, circular-dep check, andapi-report:checkall clean (no public API change).📝 Checklist
sendDefaultPIIis enabled.🔮 Next steps