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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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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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.