Add start crash reproducer for #3773

[mrousavy]

Summary

• adds an event-driven simple-camera repro loop for Race-condition crash in HybridCameraSession.start() — attach-side sibling of #3730 (iPhone 11, iOS 18.7.7, v5.0.4) #3773
• adds a high-level <Camera> Harness test that repeatedly replaces outputs/constraints and immediately restarts from lifecycle callbacks
• documents current crash-stack analysis, local device observations, and evidence boundaries in START_CRASH_FINDINGS.md

Current findings

The issue stack proves AVCaptureSession.startRunning() overlaps AVFoundation/CoreMedia's private configuration-commit notification path on FigCaptureSessionNotificationQueue. VisionCamera serializes configure() and start() on its own queue, so the current root-cause candidate is that commitConfiguration() returns before AVFoundation has fully drained its private "make configuration live" work, and the next queued startRunning() can race output attachment.

I have not reproduced the exact assertion locally yet. The iPhone SE 3rd gen completed roughly 480 cycles without crashing; the iPhone 15 Pro was later locked and denied further launches. The Harness test is intended to make CI the next real-device signal.

Verification

• bun run build
• bunx tsc --noEmit --project apps/simple-camera/tsconfig.json
• git diff --check
• bun --cwd apps/simple-camera react-native bundle --platform ios --dev true --entry-file index.js --bundle-output /tmp/simple-camera-start-crash.bundle --assets-dest /tmp/simple-camera-start-crash-assets --reset-cache

Biome reported only pre-existing unused-variable warnings in CameraScreen.tsx; the new Harness file had no Biome diagnostics.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
react-native-vision-camera-docs	Ready	Preview, Comment	Jun 5, 2026 6:03pm