fix(android-fragment): support detach/attach navigation in fragment tracing

[romtsn]

Summary

Fixes a silent data quality issue where detach/attach tab navigation (and similar patterns) left ui.load spans open until the 30-second activity transaction deadline, producing badly inflated performance data.

Root cause

SentryFragmentLifecycleCallbacks started spans in onFragmentCreated and stopped them in onFragmentStarted (a concession to ViewPager2 which locks background fragments to STARTED). For detach/attach navigation — manual tab switching (transaction.detach(current).attach(next).commit()), ViewPager v1 with FragmentPagerAdapter, and custom navigation frameworks that preserve fragment state — onFragmentCreated is never called for off-screen fragments. Spans would hang silently until the deadline.

Fix

Three targeted changes, all leveraging the fact that startTracing / stopTracing are already idempotent:

Hook	Change	Why
onFragmentViewCreated	+startTracing	Enables narrower viewCreated → resumed span for detach/attach paths. No-op if onFragmentCreated already started a span.
onFragmentResumed	+stopTracing	Ends the span on the detach/attach path where onFragmentStarted may not fire. No-op for the normal path where onFragmentStarted already closed the span.
onFragmentViewDestroyed	+stopTracing	Failsafe: closes any span for a fragment whose view is destroyed before reaching STARTED or RESUMED.

The normal lifecycle path (onFragmentCreated → onFragmentViewCreated → onFragmentStarted → onFragmentResumed) is completely unaffected — still produces exactly one ui.load span, closed at onFragmentStarted.

What's new for customers

Apps using detach/attach navigation will now see correct, narrower ui.load spans (viewCreated → resumed) instead of timeout-inflated spans. The Bol.com workaround described in the issue context is no longer needed.

Tests

Five new unit tests covering:

• Detach/attach path: onFragmentViewCreated starts a span when tracing enabled
• Normal path: onFragmentViewCreated is a no-op when span already running
• Detach/attach path: onFragmentResumed stops the span
• Normal path: onFragmentResumed does not double-finish after onFragmentStarted
• Failsafe: onFragmentViewDestroyed stops a span that never reached STARTED/RESUMED

Not verified

./gradlew spotlessApply apiDump could not run (no JDK in sandbox) — CI will apply formatting and regenerate .api files if needed.

[github-actions]

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## Unreleased

### Fixes

- support detach/attach navigation in fragment tracing ([#5660](https://github.com/getsentry/sentry-java/pull/5660))

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[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.46.0 (1)	release

⚙️ sentry-android Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	324.00 ms	379.38 ms	55.38 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
4e3e79d	312.02 ms	376.24 ms	64.22 ms
22ff2c7	306.60 ms	336.65 ms	30.05 ms
694d587	305.45 ms	378.38 ms	72.94 ms
b8bd880	314.56 ms	336.50 ms	21.94 ms
a416a65	295.53 ms	373.74 ms	78.21 ms
d15471f	379.40 ms	470.76 ms	91.36 ms
05aa61d	326.06 ms	385.46 ms	59.40 ms
fc5ccaf	279.11 ms	353.34 ms	74.23 ms
6b019b7	319.84 ms	333.15 ms	13.31 ms
6405ec5	310.88 ms	354.56 ms	43.69 ms

App size

Revision	Plain	With Sentry	Diff
4e3e79d	0 B	0 B	0 B
22ff2c7	0 B	0 B	0 B
694d587	1.58 MiB	2.19 MiB	620.06 KiB
b8bd880	1.58 MiB	2.29 MiB	722.92 KiB
a416a65	1.58 MiB	2.12 MiB	555.26 KiB
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
05aa61d	0 B	0 B	0 B
fc5ccaf	1.58 MiB	2.13 MiB	557.54 KiB
6b019b7	0 B	0 B	0 B
6405ec5	1.58 MiB	2.12 MiB	552.23 KiB