Android: Hybrid Views receive no base ViewProps on React Native >= 0.86

[ronickg]

What happened?

ViewComponentDescriptor::cloneProps overrides React Native's implementation and
does not call initializeDynamicProps. Up to RN 0.85 that was harmless, because
Props::Props called it for you via Props::initialize. RN 0.86 removed that, so
nothing fills Props::rawProps for a Hybrid View any more — and on Android that
map is exactly what gets serialized to Java and applied by
ViewManager.updateProperties.

The effect: a Hybrid View silently receives no backgroundColor, border*,
transform, opacity, testID or accessibility props on Android. iOS is
unaffected, because RCTViewComponentView reads the typed C++ fields directly.

Nothing warns, because React Native never sees a prop to report as unsupported.

Left is a plain RN View, right is TestView, same style object, on RN 0.87.1
with no feature flags and an otherwise unmodified example app:

opacity is the prop to watch: TestView paints its own surface, which masks
whether backgroundColor arrived, but nothing native can override a view's alpha.

Why it happens. Props::rawProps has exactly one writer per RN version:

	writers of Props::rawProps
RN 0.85.3	Props::initialize (from the constructor) + ConcreteComponentDescriptor::cloneProps
RN 0.87.1	ConcreteComponentDescriptor::cloneProps only

(ShadowNode::propsForClonedShadowNode also touches it, but it is gated on
!rawProps.empty() — it merges, it cannot create.)

Android then does, in SurfaceMountingManager.kt:

viewState.currentProps = ReactStylesDiffMap(props)
viewManager.updateProperties(view, viewState.currentProps)

An empty rawProps means an empty ReactStylesDiffMap, so every @ReactProp
setter on BaseViewManager is skipped.

One corroborating detail: nitrogen generates a per-view filterObjectKeys and
threads it through ViewProps → BaseViewProps → YogaStylableProps → Props, where
React Native's only consumer of it is rawProps.toDynamic(filterObjectKeys) inside
initializeDynamicProps. Without that call it is dead code.

Suggested fix (this is what #1655 does):

auto newProps = TShadowNode::Props(context, /* & */ rawProps, props);
#ifdef RN_SERIALIZABLE_STATE
  TShadowNode::initializeDynamicProps(newProps, rawProps, props);
#endif
return newProps;

It does add a rawProps.toDynamic() per props clone, which may be part of what the
override was avoiding — if you'd prefer something narrower (serializing only base
ViewProps keys), happy to rework it.

Why the harness never caught this. It couldn't: on the pinned 0.85.3 the
constructor still fills the map, so the bug has no observable effect. With
enableExclusivePropsUpdateAndroid on — the path 0.86+ takes unconditionally — it
does, and not subtly. queryByTestId resolves against the native view tree and
testID is itself a base view prop, so most of the file can't find the view it
just rendered:

full nitro.views.harness, Pixel 9 API 36 emulator, flag on

  without the fix ....  8 failed,  2 passed
  with it ............  10 passed

Six of those eight are existing tests.

Reproductions, both off b06f548 and buildable as-is:

branch	what it is
bump/rn-0.87	RN 0.87.1 + the two boxes above on the example's View tab. No fix, no flags. Build it, open the View tab — that is the screenshot.
#1655	the fix, the flag that lets the harness exercise it, and tests

Reproduceable Code

const box = {
width: 120,
height: 120,
backgroundColor: '#00C000',
transform: [{ rotate: '10deg' }],
opacity: 0.4,
} as const

// Same style object on both. On Android the Nitro view ignores all of it.

Relevant log output

ViewComponentDescriptor::cloneProps instrumented to print newProps->rawProps.size()

example on RN 0.85.3, flag off (today's default) ........ 5
example on RN 0.85.3, enableExclusivePropsUpdateAndroid . 0 (13,405 consecutive clones)
example on RN 0.87.1, unpatched ......................... 0 (6,508 consecutive clones)
our own app on RN 0.87.1, patched ....................... 102

Nothing is logged by React Native in the broken case - an empty rawProps means

an empty ReactStylesDiffMap, so there is no unsupported prop for it to warn about.

Device

Pixel 9 API 36 emulator (Android 16, arm64). Not tested on physical hardware; the iOS claim above is from reading RCTViewComponentView, not a measurement.

Nitro Modules Version

0.37.1, and main (b06f548)

Nitrogen Version

0.37.1

Can you reproduce this issue in the Nitro Example app here?

Yes, I can reproduce the same issue in the Example app here

Additional information

• I am using Expo
• I am using nitrogen
• I have read and followed the Troubleshooting Guide.
• I created a reproduction PR to reproduce this issue here in the nitro repo. (See Contributing for more information)
• I searched for similar issues in this repository and found none.