The useEffect at line 69 lists userOnReady as a dependency, so it re-fires—calling the user's onReady callback again—every time the parent re-renders with a new inline function reference, which is the common case.

Also found at:

• packages/core/test/NavigationContainer.missing.test.tsx:42-48
• samples/react-native-macos/src/App.tsx:172

In NavigationContainer.tsx the fallback useEffect (lines 71-75) lists userOnReady as a dependency and has no guard. When @react-navigation/native is not installed and the parent passes an inline onReady={() => …}, every parent re-render produces a new function reference, causing the effect to re-fire and invoke userOnReady repeatedly instead of once on mount. Consider capturing the callback in a ref and gating with a hasFired ref so it runs at most once, mirroring the real NavigationContainer.onReady semantics. Impact is limited because this only affects the missing-dependency fallback path, but it can surprise consumers who rely on onReady firing a single time.

Also found at:

• packages/core/src/js/NavigationContainer.tsx:69-73

The implementation's module-level _warnedNoClient and _warnedNoIntegration flags are set to true during the warning tests (lines 110–131) and are never reset between tests, so any future test in this file that re-enters those code paths won't see the expected warnings. Consider calling jest.resetModules() and re-importing in beforeEach, or exporting a reset helper for tests.