fix(flutter): Add app start screen attribute#3893
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Attach the initial screen name to streaming cold and warm app start spans without propagating it to breakdown spans. Co-Authored-By: Codex <[email protected]>
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Semver Impact of This PR🟢 Patch (bug fixes) 📋 Changelog PreviewThis is how your changes will appear in the changelog. Features
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #3893 +/- ##
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+ Coverage 87.35% 87.48% +0.12%
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Files 338 338
Lines 12286 12305 +19
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+ Hits 10733 10765 +32
+ Misses 1553 1540 -13
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Harness. |
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iOS Performance metrics 🚀
|
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 73dca78 | 1246.65 ms | 1265.42 ms | 18.76 ms |
| 3f47ea3 | 1263.90 ms | 1263.87 ms | -0.02 ms |
| d379a16 | 1239.65 ms | 1237.52 ms | -2.13 ms |
| 667e3c4 | 1254.70 ms | 1268.23 ms | 13.52 ms |
| 114239b | 1225.74 ms | 1230.17 ms | 4.43 ms |
| a10aff4 | 1241.67 ms | 1255.02 ms | 13.35 ms |
| 9993fa9 | 1255.60 ms | 1254.31 ms | -1.29 ms |
| dc53d48 | 1252.06 ms | 1255.61 ms | 3.55 ms |
| c1e775e | 1263.08 ms | 1275.32 ms | 12.24 ms |
| 38a22c2 | 1257.60 ms | 1259.71 ms | 2.12 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 73dca78 | 7.86 MiB | 9.44 MiB | 1.58 MiB |
| 3f47ea3 | 5.53 MiB | 5.96 MiB | 444.81 KiB |
| d379a16 | 5.83 MiB | 6.28 MiB | 459.63 KiB |
| 667e3c4 | 5.83 MiB | 6.28 MiB | 459.83 KiB |
| 114239b | 5.53 MiB | 5.96 MiB | 444.85 KiB |
| a10aff4 | 5.53 MiB | 6.00 MiB | 486.71 KiB |
| 9993fa9 | 5.83 MiB | 6.28 MiB | 459.39 KiB |
| dc53d48 | 5.65 MiB | 6.09 MiB | 446.96 KiB |
| c1e775e | 20.70 MiB | 22.46 MiB | 1.75 MiB |
| 38a22c2 | 5.73 MiB | 6.17 MiB | 453.62 KiB |
Previous results on branch: feat/span-streaming-app-vitals-start-screen
Startup times
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 441dff1 | 1245.45 ms | 1249.36 ms | 3.91 ms |
| 213ebea | 1262.19 ms | 1268.52 ms | 6.33 ms |
| ca88602 | 1243.00 ms | 1242.43 ms | -0.57 ms |
| 9bbd705 | 1254.45 ms | 1254.43 ms | -0.02 ms |
| 549f935 | 1256.57 ms | 1253.84 ms | -2.72 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 441dff1 | 5.83 MiB | 6.28 MiB | 460.59 KiB |
| 213ebea | 5.83 MiB | 6.28 MiB | 460.58 KiB |
| ca88602 | 5.83 MiB | 6.28 MiB | 460.58 KiB |
| 9bbd705 | 5.83 MiB | 6.28 MiB | 460.67 KiB |
| 549f935 | 5.83 MiB | 6.28 MiB | 460.59 KiB |
Contributor
Android Performance metrics 🚀
|
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| fd88186 | 422.07 ms | 469.10 ms | 47.03 ms |
| d5a1225 | 377.37 ms | 366.56 ms | -10.81 ms |
| 1980dca | 354.77 ms | 346.96 ms | -7.82 ms |
| d0371bb | 426.85 ms | 437.14 ms | 10.29 ms |
| bfabaf2 | 408.04 ms | 444.38 ms | 36.34 ms |
| 7b21e8b | 467.74 ms | 466.24 ms | -1.50 ms |
| 2f63d89 | 415.95 ms | 424.21 ms | 8.26 ms |
| 0265ce5 | 406.39 ms | 418.48 ms | 12.09 ms |
| 7cfee3b | 498.78 ms | 516.98 ms | 18.20 ms |
| 6f47800 | 451.04 ms | 509.64 ms | 58.60 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| fd88186 | 13.93 MiB | 15.00 MiB | 1.06 MiB |
| d5a1225 | 14.31 MiB | 15.49 MiB | 1.19 MiB |
| 1980dca | 14.55 MiB | 15.87 MiB | 1.31 MiB |
| d0371bb | 14.31 MiB | 15.62 MiB | 1.31 MiB |
| bfabaf2 | 13.93 MiB | 15.06 MiB | 1.13 MiB |
| 7b21e8b | 13.93 MiB | 15.00 MiB | 1.06 MiB |
| 2f63d89 | 14.09 MiB | 15.28 MiB | 1.19 MiB |
| 0265ce5 | 14.09 MiB | 15.28 MiB | 1.19 MiB |
| 7cfee3b | 6.54 MiB | 7.70 MiB | 1.17 MiB |
| 6f47800 | 6.54 MiB | 7.69 MiB | 1.15 MiB |
Previous results on branch: feat/span-streaming-app-vitals-start-screen
Startup times
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 441dff1 | 347.68 ms | 358.04 ms | 10.36 ms |
| ca88602 | 358.16 ms | 367.40 ms | 9.24 ms |
| 213ebea | 392.60 ms | 395.90 ms | 3.30 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 441dff1 | 14.55 MiB | 15.87 MiB | 1.31 MiB |
| ca88602 | 14.55 MiB | 15.87 MiB | 1.31 MiB |
| 213ebea | 14.55 MiB | 15.87 MiB | 1.31 MiB |
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Pull request overview
This PR adds a new app-start vitals dimension (app.vitals.start.screen) to the streaming app-start parent spans (app.start.cold / app.start.warm), using the initial route/root span name, while keeping the attribute off breakdown phase spans and native child spans.
Changes:
- Add
SemanticAttributesConstants.appVitalsStartScreen. - Attach
app.vitals.start.screento the streaming app-start parent span inNativeAppStartHandlerV2. - Add Flutter integration tests covering cold/warm behavior and non-propagation to breakdown spans.
Axis Review (Standards / Spec / Correctness)
- Standards: Minor test consistency issue: new tests use raw string keys instead of
SemanticAttributesConstants.*like the rest of the file. - Spec: The implementation matches the stated behavior (attribute added to the parent app-start span only). The tests currently assert non-propagation to breakdown spans, but they do not assert non-propagation to native child spans (also called out in the PR description).
- Correctness: The production change is low-risk and correctly avoids mutating the shared
attributesmap (children keep the old map, parent gets a new one).
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| packages/flutter/lib/src/integrations/native_app_start_handler_v2.dart | Adds app.vitals.start.screen to the streaming app-start parent span attributes. |
| packages/dart/lib/src/constants.dart | Introduces a new semantic attribute constant for the screen dimension. |
| packages/flutter/test/integrations/native_app_start_handler_v2_test.dart | Adds regression tests for cold/warm spans and verifies the attribute is absent on breakdown phase spans. |
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Verify app.vitals.start.screen remains scoped to the parent span and is not propagated to native child spans. Co-Authored-By: Codex <[email protected]>
Match Flutter-bundled dart_style so analyze CI passes. Co-Authored-By: Cursor Grok 4.5 <[email protected]> Co-authored-by: Cursor <[email protected]>
lucas-zimerman
approved these changes
Jul 16, 2026
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Left a non-blocking question, LGTM!
![sentry[bot]](https://avatars.githubusercontent.com/in/12637?s=60&v=4){kind=small}
Preserve the first observed route on the prepared app-start trace so custom launch routes populate the screen dimension. Keep root and unknown routes mapped to root /. Co-Authored-By: Codex <[email protected]>
This was referenced Jul 21, 2026
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📜 Description
Add
app.vitals.start.screento streamingapp.start.coldandapp.start.warmparent spans using the initial display span name. Keep the attribute off app-start breakdown and native child spans.💡 Motivation and Context
Streaming app-start spans already report duration and start type, but omit the initial screen dimension required for mobile-vitals analysis.
💚 How did you test it?
📝 Checklist
🔮 Next steps
None.