fix(ios): blank RiveView after Fabric recreates the component view (react-freeze) — props skipped by consumed isDirty flags

scripts/nitrogen-postprocess.ts

@@ -10,6 +10,10 @@ const COMPONENT_FILE = join(
   ROOT,
   'nitrogen/generated/shared/c++/views/HybridRiveViewComponent.cpp'
 );
+const IOS_COMPONENT_FILE = join(
+  ROOT,
+  'nitrogen/generated/ios/c++/views/HybridRiveViewComponent.mm'
+);
 
 function makeHybridRiveViewManagerOpen() {
   if (!existsSync(MANAGER_FILE)) {
@@ -44,6 +48,10 @@ function acceptNullForOptionalProps() {
   }
 
   const content = readFileSync(COMPONENT_FILE, 'utf-8');
+  if (content.includes('value.isNull()')) {
+    console.log('HybridRiveViewComponent.cpp already accepts null props');
+    return;
+  }
   const pattern =
     /^( *)return (CachedProp<std::optional<.+>>)::fromRawValue\(\*runtime, value, (sourceProps\.\w+)\);$/gm;
   const updated = content.replace(
@@ -53,13 +61,9 @@ function acceptNullForOptionalProps() {
   );
 
   if (content === updated) {
-    if (content.includes('value.isNull()')) {
-      console.log('HybridRiveViewComponent.cpp already accepts null props');
-    } else {
-      console.warn(
-        'No optional CachedProp parse sites found in HybridRiveViewComponent.cpp — nitrogen output may have changed shape'
-      );
-    }
+    console.warn(
+      'No optional CachedProp parse sites found in HybridRiveViewComponent.cpp — nitrogen output may have changed shape'
+    );
     return;
   }
 
@@ -69,5 +73,74 @@ function acceptNullForOptionalProps() {
   );
 }
 
+// Fabric can recreate the iOS component view from an unchanged ShadowNode
+// (e.g. react-freeze / Suspense re-inserting a previously hidden screen), but
+// the cached props' isDirty flags were already consumed by the previous view
+// instance (they live on the shared Props object and are mutated on first
+// apply), so updateProps would apply nothing and the fresh view would stay
+// unconfigured: no file, no artboard, and a hybridRef that never fires.
+// Force-apply every prop on a view instance's first updateProps.
+// Fixed upstream in nitro 0.37 (props are diffed against oldProps instead of
+// mutating shared isDirty state) — remove on the next nitro upgrade:
+// https://github.com/mrousavy/nitro/pull/1506
+const IVAR_BLOCK = `  // Fabric can recreate this component view from an unchanged ShadowNode
+  // (e.g. react-freeze / Suspense re-inserting a previously hidden screen).
+  // The cached props' isDirty flags were already consumed by the previous
+  // view instance (they live on the shared Props object and are mutated on
+  // first apply), so updateProps would apply nothing and the fresh
+  // HybridRiveView would stay unconfigured: no file, no artboard, and a
+  // hybridRef that never fires (JS keeps a ref to the dead old hybrid).
+  // Force-apply every prop on this instance's first updateProps.
+  BOOL _didApplyInitialProps;
+`;
+
+const FORCE_BLOCK = `
+  // Force-apply all props the first time this view instance updates (see
+  // _didApplyInitialProps above).
+  BOOL force = !_didApplyInitialProps;
+  _didApplyInitialProps = YES;
+`;
+
+function forceApplyPropsOnFirstUpdate() {
+  if (!existsSync(IOS_COMPONENT_FILE)) {
+    console.warn('HybridRiveViewComponent.mm not found, skipping');
+    return;
+  }
+
+  const content = readFileSync(IOS_COMPONENT_FILE, 'utf-8');
+  if (content.includes('_didApplyInitialProps')) {
+    console.log(
+      'HybridRiveViewComponent.mm already force-applies initial props'
+    );
+    return;
+  }
+
+  const ivarAnchor =
+    '  std::shared_ptr<HybridRiveViewSpecSwift> _hybridView;\n';
+  const updateAnchor = '\n  // 2. Update each prop individually\n';
+  const dirtyPattern = /if \(newViewProps\.(\w+)\.isDirty\)/g;
+  if (
+    !content.includes(ivarAnchor) ||
+    !content.includes(updateAnchor) ||
+    !dirtyPattern.test(content)
+  ) {
+    console.warn(
+      'Anchors for the force-apply patch not found in HybridRiveViewComponent.mm — nitrogen output may have changed shape'
+    );
+    return;
+  }
+
+  const updated = content
+    .replace(ivarAnchor, `${ivarAnchor}${IVAR_BLOCK}`)
+    .replace(updateAnchor, `${FORCE_BLOCK}${updateAnchor}`)
+    .replace(dirtyPattern, 'if (force || newViewProps.$1.isDirty)');
+
+  writeFileSync(IOS_COMPONENT_FILE, updated);
+  console.log(
+    'Patched HybridRiveViewComponent.mm to force-apply props on first update'
+  );
+}
+
 makeHybridRiveViewManagerOpen();
 acceptNullForOptionalProps();
+forceApplyPropsOnFirstUpdate();