perf(android): Avoid exception-driven control flow in getResourceId#5631
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perf(android): Avoid exception-driven control flow in getResourceId#5631runningcode wants to merge 2 commits into
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Always a win! One optional nit if you want it 💯
| * @param view - the view whose id is being retrieved | ||
| * @return human-readable view id, or {@code null} if it cannot be resolved | ||
| */ | ||
| public static @Nullable String resolveResourceId(final @NotNull View view) { |
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l: Thoughts about getResourceIdOrNull() to parallel getResourceId()?
Up to you, of course...
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good idea. will add!
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on second though I also removed the other method that throws since it is unused, internal and not part of our public api. gonna ask for a re-review
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Performance metrics 🚀
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| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 4e3e79d | 369.55 ms | 418.39 ms | 48.83 ms |
| 22ff2c7 | 306.60 ms | 336.65 ms | 30.05 ms |
| 092f017 | 353.13 ms | 433.84 ms | 80.71 ms |
| 0eaac1e | 322.53 ms | 389.31 ms | 66.78 ms |
| d15471f | 322.58 ms | 396.08 ms | 73.50 ms |
| fc5ccaf | 322.49 ms | 405.25 ms | 82.76 ms |
| e2dce0b | 315.85 ms | 369.20 ms | 53.35 ms |
| 22f4345 | 314.79 ms | 375.02 ms | 60.23 ms |
| 9770665 | 315.64 ms | 378.00 ms | 62.36 ms |
| 7314dbe | 437.83 ms | 505.64 ms | 67.81 ms |
App size
| Revision | Plain | With Sentry | Diff |
|---|---|---|---|
| 4e3e79d | 0 B | 0 B | 0 B |
| 22ff2c7 | 0 B | 0 B | 0 B |
| 092f017 | 0 B | 0 B | 0 B |
| 0eaac1e | 1.58 MiB | 2.19 MiB | 619.17 KiB |
| d15471f | 1.58 MiB | 2.13 MiB | 559.54 KiB |
| fc5ccaf | 1.58 MiB | 2.13 MiB | 557.54 KiB |
| e2dce0b | 0 B | 0 B | 0 B |
| 22f4345 | 1.58 MiB | 2.29 MiB | 719.83 KiB |
| 9770665 | 0 B | 0 B | 0 B |
| 7314dbe | 1.58 MiB | 2.10 MiB | 533.45 KiB |
ViewUtils.getResourceId threw Resources.NotFoundException for views with no id or a generated id, and callers caught and discarded it. During a view-hierarchy snapshot and on every gesture this ran per view, so in Compose-heavy apps where most views have generated ids the SDK constructed an exception (and a native stack trace fill) per view on the main thread. Add a non-throwing resolveResourceId that returns null for unresolved ids and route the hot callers through it. The public getResourceId remains as a throwing wrapper for backward compatibility. Behavior (emitted identifiers and fallbacks) is unchanged. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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| * @throws Resources.NotFoundException in case the view id was not found | ||
| * @return human-readable view id, or {@code null} if it cannot be resolved | ||
| */ | ||
| public static String getResourceId(final @NotNull View view) throws Resources.NotFoundException { |
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this old method signature was removed so it is a breaking change but not part of the public api
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Resolves JAVA-586
📜 Description
ViewUtils.getResourceIdused exception-driven control flow: it threwResources.NotFoundExceptionfor views withView.NO_IDor a generated id, and every caller caught and discarded it. This ran per view during view-hierarchy snapshots and gesture target resolution, so in Compose-heavy apps — where most views have generated ids — the SDK constructed an exception (and a nativefillInStackTracestack walk) for nearly every view, on the main thread.This adds a non-throwing
ViewUtils.resolveResourceId(View)that returnsnullfor unresolved ids, and routes the hot callers (ViewHierarchyEventProcessor.viewToNode,AndroidViewGestureTargetLocator.createUiElement,getResourceIdWithFallback) through it. The publicgetResourceId(...) throws Resources.NotFoundExceptionstays as a thin wrapper for backward compatibility. Emitted identifiers and fallbacks are unchanged.💡 Motivation and Context
Found while analyzing a customer-provided Perfetto trace: in a single view-hierarchy snapshot, 24 of 72
getResourceIdcalls threwResources.NotFoundExceptionon the main thread — pure overhead with no functional result.💚 How did you test it?
Unit tests in
ViewUtilsTestcover the newresolveResourceId(generated id,NO_ID, resource-not-found, and success) plus the existinggetResourceId/fallback behavior;ViewHierarchyEventProcessorTestandAndroidViewGestureTargetLocatorTestpass unchanged.On-device A/B on a Pixel 3 (Android 12) via ART method tracing, analyzed in Perfetto
trace_processor, over 2048 calls onNO_IDviews:getResourceId)resolveResourceId)Resources$NotFoundException.<init>Throwable.fillInStackTraceExactly one exception (+ native stack fill) per unresolved view is removed; ~60% fewer executed methods and ~4.7× cheaper per unresolved view (the absolute ns is inflated by tracing; the call counts and ratio are the reliable signal).
📝 Checklist
sendDefaultPIIis enabled.🔮 Next steps
Follow-ups identified in the same trace but intentionally out of scope here: per-touch
LinkedList→ArrayDequeinViewUtils.findTarget, and background JSON serialization cost.