LegendList + Relay integration bug repro

.babelrc

@@ -0,0 +1,4 @@
+{
+  "presets": ["module:@react-native/babel-preset"],
+  "plugins": ["relay"]
+}

.gitignore

@@ -4,3 +4,4 @@ example/android
 example/ios
 legendapp-list.tgz
 tsconfig.tsbuildinfo
+__generated__/*.graphql.ts

__tests__/__mocks__/react-native.ts

@@ -1,4 +1,5 @@
 // Minimal React Native stub for Bun test environment
+import * as React from "react";
 
 type AnyFunction = (...args: any[]) => any;
 
@@ -12,6 +13,28 @@ export type LayoutChangeEvent = any;
 export type NativeScrollEvent = any;
 export type NativeSyntheticEvent<T> = { nativeEvent: T };
 
+const createMockComponent = (displayName: string, options?: { triggerLayout?: boolean }) => {
+    const Component = React.forwardRef<any, any>((props, _ref) => {
+        React.useEffect(() => {
+            if (options?.triggerLayout && typeof props.onLayout === "function") {
+                props.onLayout({
+                    nativeEvent: {
+                        layout: {
+                            height: props.__mockHeight ?? 600,
+                            width: props.__mockWidth ?? 375,
+                            x: 0,
+                            y: 0,
+                        },
+                    },
+                });
+            }
+        }, []);
+        return React.createElement(React.Fragment, null, props.children);
+    });
+    Component.displayName = displayName;
+    return Component;
+};
+
 export const Platform = {
     OS: "ios",
     select<T>(spec: { ios?: T; android?: T; web?: T; default?: T }): T {
@@ -64,6 +87,8 @@ export const Animated = {
         return { start: (cb?: AnyFunction) => cb?.() };
     },
     Value: AnimatedValue,
+    View: createMockComponent("Animated.View", { triggerLayout: true }),
+    ScrollView: createMockComponent("Animated.ScrollView", { triggerLayout: true }),
 };
 
 // Provide a global requestAnimationFrame fallback for tests that expect it
@@ -72,11 +97,35 @@ if (typeof globalThis.requestAnimationFrame !== "function") {
     globalThis.requestAnimationFrame = (cb: AnyFunction) => setTimeout(cb, 0);
 }
 
+// FlatList mock that renders items
+export const FlatList = React.forwardRef<any, any>((props, _ref) => {
+    const { data, renderItem, keyExtractor } = props;
+
+    if (!data || !renderItem) {
+        return null;
+    }
+
+    return React.createElement(
+        React.Fragment,
+        null,
+        data.map((item: any, index: number) => {
+            const key = keyExtractor ? keyExtractor(item, index) : String(index);
+            return React.createElement(
+                React.Fragment,
+                { key },
+                renderItem({ item, index })
+            );
+        })
+    );
+});
+FlatList.displayName = "FlatList";
+
 // Very light component stubs
-export const View = (() => null) as unknown as AnyFunction;
-export const Text = (() => null) as unknown as AnyFunction;
-export const RefreshControl = ((_props: any) => null) as unknown as AnyFunction;
-export const ScrollView = (() => null) as unknown as AnyFunction;
+export const View = createMockComponent("View", { triggerLayout: true }) as unknown as AnyFunction;
+export const Text = createMockComponent("Text") as unknown as AnyFunction;
+export const RefreshControl = createMockComponent("RefreshControl") as unknown as AnyFunction;
+export const ScrollView = createMockComponent("ScrollView", { triggerLayout: true }) as unknown as AnyFunction;
 
 export type View = any; // for type-only imports
 export type ScrollView = any; // for type-only imports
+export type FlatList = any; // for type-only imports

babel.config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  presets: ['module:@react-native/babel-preset'],
+  plugins: ['relay'],
+};

biome.json

@@ -21,7 +21,7 @@
     },
     "files": {
         "ignoreUnknown": false,
-        "includes": ["**/*.ts", "**/*.tsx"]
+        "includes": ["**/*.ts", "**/*.tsx", "!**/*.generated.ts"]
     },
     "formatter": {
         "enabled": true,

bunfig.toml

@@ -2,4 +2,4 @@
 saveTextLockfile = true
 
 [test]
-preload = ["./__tests__/setup.ts"]
+preload = ["./__tests__/setup.ts"]