Sentry 8.8.0 ios crash on startup

[gkartalis]

What React Native libraries do you use?

RN New Architecture

Are you using sentry.io or on-premise?

sentry.io (SaS)

Are you using any other error monitoring solution alongside Sentry?

No

Other Error Monitoring Solution Name

No response

@sentry/react-native SDK Version

8.8.0

How does your development environment look like?

System:
  OS: macOS 26.3.1
  CPU: (12) arm64 Apple M2 Pro
  Memory: 111.80 MB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 24.6.0
    path: ~/.local/share/mise/installs/node/24.6.0/bin/node
  Yarn:
    version: 4.10.3
    path: ~/.local/share/mise/installs/yarn/4.10.3/bin/yarn
  npm:
    version: 11.5.1
    path: ~/.local/share/mise/installs/node/24.6.0/bin/npm
  Watchman:
    version: 2026.01.12.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /Users/georgioskartalis/.local/share/mise/installs/ruby/3.1.7/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 25.2
      - iOS 26.2
      - macOS 26.2
      - tvOS 26.2
      - visionOS 26.2
      - watchOS 26.2
  Android SDK:
    API Levels:
      - "30"
      - "31"
      - "34"
      - "35"
      - "36"
    Build Tools:
      - 33.0.1
      - 34.0.0
      - 35.0.0
      - 36.0.0
      - 36.1.0
    System Images:
      - android-30 | Google APIs ARM 64 v8a
      - android-34 | Google Play ARM 64 v8a
      - android-35 | Google Play ARM 64 v8a
      - android-35 | Pre-Release 16 KB Page Size Google Play ARM 64 v8a
      - android-35 | Google Play Tablet ARM 64 v8a
      - android-36.1 | Pre-Release 16 KB Page Size Google Play ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2025.2 AI-252.28238.7.2523.14688667
  Xcode:
    version: 26.2/17C52
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.11
    path: /Users/georgioskartalis/.local/share/mise/installs/java/zulu-17.50.19.0/bin/javac
  Ruby:
    version: 3.1.7
    path: /Users/georgioskartalis/.local/share/mise/installs/ruby/3.1.7/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 20.0.0
    wanted: 20.0.0
  react:
    installed: 19.1.0
    wanted: 19.1.0
  react-native:
    installed: 0.81.5
    wanted: patch:react-native@npm%3A0.81.5#~/.yarn/patches/react-native-npm-0.81.5-d8232ef145.patch
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Sentry.init()

sentry.options.json:

{
  "dsn": "sentryDSN"
}

Sentry.init({
    dsn: sentryDSN,
    release: eigenSentryReleaseName(),
    dist: eigenSentryDist(),
    enableTombstone: true,
    enableAutoSessionTracking: true,
    enableWatchdogTerminationTracking: false,
    attachStacktrace: true,
    tracesSampleRate: props.debug ? 1.0 : 0.05,
    profilesSampleRate: props.debug ? 1.0 : 0.05,
    debug: props.debug,
    integrations: [navigationInstrumentation],
    ...props,
  })

https://github.com/artsy/eigen/blob/f45e104a159a69b7e179adb2255c8537e5c18315/src/app/system/errorReporting/setupSentry.ts#L62-L75

Steps to Reproduce

We migrated to version 8.8.0 like so

artsy/eigen#13505

but it is resulting in crashes on startup only on iOS, android works as expected

Expected Result

We expected the app to run normally on iOS, we also expected sentry.init to override the release created on Sentry with the custom name as stated in the docs.

Actual Result

iOS crashes on launch with error -> https://artsynet.sentry.io/issues/7434131499/events/68ffc8c0ea674b378f6ec1a92fd700d0/

It ends up creating two Sentry releases per environment. My assumption is that one comes from the native initialization and the other from the JS Sentry setup. This also introduces another problem: for native crashes, the dSYMs aren’t uploaded to the correct release—specifically, the native one.

[linear-code]

RN-596

[antonis]

Thank you for reporting 🙇 We are looking into this.

[antonis]

The crash is in Hermes unstable_initializeOnJsThread with no Sentry frames in the stack. However, RNSentrySDK.start() installs mach exception/signal handlers before Hermes starts, which could interfere with signals Hermes uses internally during initialization.

To diagnose:

1. Temporarily remove RNSentrySDK.start() from AppDelegate and check if the app still crashes on launch. If it does, this is a Hermes/RN issue unrelated to Sentry. If it doesn't, Sentry's early init is triggering it.
2. If removing it fixes the crash, try re-adding it with the crash handler disabled to confirm:

RNSentrySDK.start { options in
      options.enableCrashHandler = false
}

We expected the app to run normally on iOS, we also expected sentry.init to override the release created on Sentry with the custom name as stated in the docs.

This is expected when native init auto-detects the release but JS uses a custom format. Pre-JS crashes get the native release, post-JS events get the JS release. This is indeed a documentation gap. Sorry for this.

To fix this, add matching release and dist values to your sentry.options.json:

  {                                                         
    "dsn": "...",
    "release": "ios-<version>-<buildNumber>",
    "dist": "<buildNumber>"
  }

We're also working on SENTRY_RELEASE/SENTRY_DIST env var support in the build scripts to make this easier.