🐛 Android: rerendering <Camera> without a previously set onPreviewStarted throws "PreviewView.onPreviewStarted: Value is null, expected an Object" #4208

Prerequisites

• I have read and followed every applicable step in the Nitro Modules Troubleshooting guide.
• I have read the VisionCamera Troubleshooting guide.
• I have searched existing issues and found nothing matching.
• I am on the latest version of react-native-vision-camera, or have a specific reason I cannot upgrade.

Reproduction

margelo/nitro#1671 (fix in Nitro). Existing harness test in visioncamera.camera-view.harness.tsx, 'reconfigures when the Camera device position prop changes'

Steps to reproduce

1. Build the example app and run the camera-view tests on an Android phone: bun run test:harness:android -- --testPathPatterns=camera-view
2. Watch the test named "reconfigures when the Camera device position prop changes". It fails.
3. Or in app: show , then show it again as with onPreviewStarted left out. It throws instead of switching camera.

What did you expect to happen?

Dropping an optional callback prop on a rerender is allowed and the view just stops calling it.

What actually happened?

The rerender drops onPreviewStarted, React Native passes it as null, and Nitro's ReactProp::fromRawValue calls asObject() on it before JSIConverter<std::optional> can treat it as absent. The throw from cloneNodeWithNewProps is caught by the ErrorBoundary and the rerender never completes.

Fix in Nitro: margelo/nitro PR #1671. With it the test passes on the A14.

Affected platforms

Android (device)

Device(s) affected

Samsung Galaxy A14 (SM-A145F), Android 15, security patch 2026-05-05

VisionCamera version

5.2.3 (main at 91bae1f)

React Native version

0.85.3

React Native architecture

New Architecture (Fabric / bridgeless)

Features being used

• Preview
• Photo capture
• Video capture
• Frame Processors (worklets)
• Skia Frame Processors
• Code/Barcode Scanner
• Location metadata
• Multi-cam
• Depth data
• HDR / custom dynamic range
• Custom format / FPS / resolution

Relevant logs / stack trace

[Error: Exception in HostFunction: PreviewView.onPreviewStarted: Value is null, expected an Object
Rerender timeout: Element did not update within 1000ms

Additional context

No response

Submission

• The reproduction I linked is either (preferred) a PR against this repo that adds a failing harness test following the harness-tests README, or (fallback) a public repo that reproduces the bug on a fresh clone. I understand the issue will be closed without one.
• I pasted logs as text (not screenshots).
• I wrote this report in my own words. I did not paste AI-generated descriptions of the bug.