fix(android): Drop inflated app start for background-spawned processes on API 35+ - #5841
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…s on API 35+ When the OS spawns the process for background work (FCM push, job, service, broadcast, etc.) and the user opens the app later, the app start stayed anchored at background process creation, inflating the reported cold start by the whole idle gap. On API 35+ we now use ApplicationStartInfo.getReason() to detect background process starts and mark them as not launched in foreground, so the first created activity re-classifies them as a warm start anchored at activity creation.
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Performance metrics 🚀
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| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 6b019b7 | 343.31 ms | 417.23 ms | 73.91 ms |
| d15471f | 342.08 ms | 415.44 ms | 73.35 ms |
| 8687935 | 332.52 ms | 362.23 ms | 29.71 ms |
| 5b1a06b | 352.27 ms | 413.70 ms | 61.43 ms |
| 91bb874 | 314.47 ms | 440.00 ms | 125.53 ms |
| 0ee65e9 | 321.06 ms | 361.24 ms | 40.18 ms |
| e63ad34 | 323.67 ms | 390.33 ms | 66.67 ms |
| 33a08cc | 267.08 ms | 340.45 ms | 73.37 ms |
| 27d7cf8 | 397.90 ms | 498.65 ms | 100.75 ms |
| ee747ae | 405.43 ms | 485.70 ms | 80.28 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 6b019b7 | 0 B | 0 B | 0 B |
| d15471f | 1.58 MiB | 2.13 MiB | 559.54 KiB |
| 8687935 | 1.58 MiB | 2.19 MiB | 619.17 KiB |
| 5b1a06b | 0 B | 0 B | 0 B |
| 91bb874 | 1.58 MiB | 2.13 MiB | 559.07 KiB |
| 0ee65e9 | 0 B | 0 B | 0 B |
| e63ad34 | 0 B | 0 B | 0 B |
| 33a08cc | 1.58 MiB | 2.12 MiB | 555.28 KiB |
| 27d7cf8 | 1.58 MiB | 2.12 MiB | 549.42 KiB |
| ee747ae | 1.58 MiB | 2.10 MiB | 530.95 KiB |
Previous results on branch: alwx/fix/appstart-background-spawn
Startup times
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 09b6604 | 315.24 ms | 354.90 ms | 39.66 ms |
| b09f940 | 314.02 ms | 363.24 ms | 49.22 ms |
| 9c32fdf | 318.18 ms | 352.44 ms | 34.26 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 09b6604 | 0 B | 0 B | 0 B |
| b09f940 | 0 B | 0 B | 0 B |
| 9c32fdf | 0 B | 0 B | 0 B |
alwx
marked this pull request as ready for review
July 28, 2026 08:01
alwx
requested review from
0xadam-brown,
adinauer,
markushi,
romtsn and
runningcode
as code owners
July 28, 2026 08:01
![sentry[bot]](https://avatars.githubusercontent.com/in/12637?s=60&v=4){kind=small}
markushi
approved these changes
Jul 30, 2026
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📜 Description
On API 35+, use
ApplicationStartInfo.getReason()to detect processes the OS spawned for background work (FCM push, job, service, broadcast, alarm, backup, boot_complete, content_provider) and mark them as not launched in foreground. The first created activity then re-classifies the launch as a warm start re-anchored at activity creation, instead of reporting the whole background idle gap as an inflated cold start.Reported by a user of RN SDK: getsentry/sentry-react-native#6382
💡 Motivation and Context
When a process is spawned in the background (e.g. by an FCM push) and the user opens the app seconds later,
appLaunchedInForegroundwas only evaluated lazily and the app start span stayed anchored at background process creation. On API 35+ the main-looper idle check that would otherwise mark the launch as headless is skipped once the start type is resolved fromApplicationStartInfo, so the inflated cold start (idle gap up to ~1 min) leaked through intoapp_start_cold.Fixes getsentry/sentry-react-native#6382
Fixes #4693
💚 How did you test it?
adb shell am broadcast -a io.sentry.samples.android.TEST_BROADCAST -p io.sentry.samples.android.debug)📝 Checklist
sendDefaultPIIis enabled.🔮 Next steps
Follow-up: API < 35 has no reliable process start reason, so a narrow race in the main-looper idle check remains there; not addressed here.