Move AssetRegistry implementation into main package

Summary:
**Problem**

The separate `react-native/assets-registry` package isn’t working for the ecosystem.

`registry.js` holds asset state in a module-scoped variable, which makes the package a stateful singleton: exactly one instance must exist per JS runtime, or registration and lookup diverge.

We provide no guarantee that this singleton requirement holds:

- The install layout — how the package manager dedupes packages in `node_modules` — decides how many copies exist, and `react-native`'s exact-version pin means third-party ranges never dedupe against it.

Effects:

- **Consumers silently break**: `expo-asset` and `expo-image` can land on a second copy: assets register in one, resolve as `undefined` from the other. Expo neutralizes this with a shim in `expo/cli` that redirects every registry import to a single virtual module — bare React Native + Metro has no such protection.
- **This blocks 1.0**: The ecosystem can't move from exact-version lockstep to semver ranges until stateful packages like the asset registry are safe to duplicate. Today, relaxing the pin would turn a latent footgun into a common one.

**To solve this**, move towards (but not quite yet) deleting `react-native/assets-registry`, in favour of a replacement `AssetRegistry` API offered directly by `react-native`.

**This diff**

- Adds new `AssetRegistry` API, along with the `PackagerAsset` and `AssetDestPathResolver` root type exports in `react-native`.
- Updates `react-native/assets-registry` to source from this relocated implementation — fixing the duplicate install layout bug (where apps/frameworks enforce a single copy of `react-native`).

**Impact**

- **✅ Fixed**: Imports from either `react-native` or `react-native/assets-registry` in RN 0.87+ will be durable to duplicate package installs — Expo can remove their virtual module shim.

Changelog:
- [General][Fixed] - **assets-registry**: `react-native/assets-registry` now shares state across duplicate installs, sourcing from a relocated implementation in the `react-native` package
- [General][Added] - Add `AssetRegistry` API (replaces `react-native/assets-registry/registry`)

Differential Revision: D108750302

Author: huntie

packages/assets-registry/README.md

@@ -10,6 +10,9 @@ Most apps never import this directly — assets are handled through `<Image>`.
 
 ### `@react-native/assets-registry/registry`
 
+> [!Note]
+> Aliases to [`AssetRegistry`](https://reactnative.dev/docs/assetregistry) (since 0.87). Prefer importing directly from the `'react-native'` package in libraries.
+
 | Export | Signature | Notes |
 |---|---|---|
 | `registerAsset` | `(asset: PackagerAsset) => number` | Stores the asset; returns a numeric ID |

packages/assets-registry/package.json

@@ -27,5 +27,8 @@
     "!**/__fixtures__/**",
     "!**/__mocks__/**",
     "!**/__tests__/**"
-  ]
+  ],
+  "peerDependencies": {
+    "react-native": "*"
+  }
 }

packages/assets-registry/src/registry.js

@@ -4,43 +4,19 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @flow strict
+ * @flow strict-local
  * @format
  */
 
 'use strict';
 
-/*::
-export type AssetDestPathResolver = 'android' | 'generic';
+import {AssetRegistry} from 'react-native';
 
-export type PackagerAsset = {
-  readonly __packager_asset: boolean,
-  readonly fileSystemLocation: string,
-  readonly httpServerLocation: string,
-  readonly width: ?number,
-  readonly height: ?number,
-  readonly scales: Array<number>,
-  readonly hash: string,
-  readonly name: string,
-  readonly type: string,
-  readonly resolver?: AssetDestPathResolver,
-  ...
-};
+/*::
+export type {AssetDestPathResolver, PackagerAsset} from 'react-native';
 */
 
-const assets /*: Array<PackagerAsset> */ = [];
-
-function registerAsset(asset /*: PackagerAsset */) /*: number */ {
-  // `push` returns new array length, so the first asset will
-  // get id 1 (not 0) to make the value truthy
-  return assets.push(asset);
-}
-
-function getAssetByID(assetId /*: number */) /*: PackagerAsset */ {
-  return assets[assetId - 1];
-}
-
 module.exports = {
-  registerAsset,
-  getAssetByID,
+  registerAsset: AssetRegistry.registerAsset,
+  getAssetByID: AssetRegistry.getAssetByID,
 };

packages/react-native/Libraries/Image/AssetSourceResolver.js

@@ -10,31 +10,10 @@
 
 'use strict';
 
-export type ResolvedAssetSource = {
-  readonly __packager_asset: boolean,
-  readonly width: ?number,
-  readonly height: ?number,
-  readonly uri: string,
-  readonly scale: number,
-};
-
-// From @react-native/assets-registry
-type AssetDestPathResolver = 'android' | 'generic';
-
-// From @react-native/assets-registry
-type PackagerAsset = Readonly<{
-  __packager_asset: boolean,
-  fileSystemLocation: string,
-  httpServerLocation: string,
-  width: ?number,
-  height: ?number,
-  scales: Array<number>,
-  hash: string,
-  name: string,
-  type: string,
-  resolver?: AssetDestPathResolver,
-  ...
-}>;
+import type {
+  AssetDestPathResolver,
+  PackagerAsset,
+} from '../../src/private/assets/AssetRegistry';
 
 const PixelRatio = require('../Utilities/PixelRatio').default;
 const Platform = require('../Utilities/Platform').default;
@@ -46,6 +25,14 @@ const {
 } = require('@react-native/assets-registry/path-support');
 const invariant = require('invariant');
 
+export type ResolvedAssetSource = {
+  readonly __packager_asset: boolean,
+  readonly width: ?number,
+  readonly height: ?number,
+  readonly uri: string,
+  readonly scale: number,
+};
+
 /**
  * Returns a path like 'assets/AwesomeModule/icon@2x.png'
  */

packages/react-native/Libraries/Image/RelativeImageStub.js

@@ -13,7 +13,7 @@
 // This is a stub for flow to make it understand require('./icon.png')
 // See metro/src/Bundler/index.js
 
-const AssetRegistry = require('@react-native/assets-registry/registry');
+const {AssetRegistry} = require('../../src/private/assets/AssetRegistry');
 
 const RelativeImageStub = AssetRegistry.registerAsset({
   __packager_asset: true,

packages/react-native/Libraries/Image/__tests__/resolveAssetSource-test.js

@@ -8,7 +8,7 @@
  * @format
  */
 
-import type {PackagerAsset} from '../../../../assets-registry/registry';
+import type {PackagerAsset} from '../../../src/private/assets/AssetRegistry';
 import type {ResolvedAssetSource} from '../AssetSourceResolver';
 
 describe('resolveAssetSource', () => {
@@ -20,7 +20,8 @@ describe('resolveAssetSource', () => {
   beforeEach(() => {
     jest.resetModules();
 
-    AssetRegistry = require('@react-native/assets-registry/registry');
+    AssetRegistry =
+      require('../../../src/private/assets/AssetRegistry').AssetRegistry;
     resolveAssetSource = require('../resolveAssetSource').default;
     NativeSourceCode =
       require('../../NativeModules/specs/NativeSourceCode').default;

packages/react-native/Libraries/Image/resolveAssetSource.js

@@ -16,10 +16,10 @@ import type {ImageSource} from './ImageSource';
 
 import SourceCode from '../NativeModules/specs/NativeSourceCode';
 
+const {AssetRegistry} = require('../../src/private/assets/AssetRegistry');
 const AssetSourceResolver: AssetSourceResolverT =
   require('./AssetSourceResolver').default;
 const {pickScale} = require('./AssetUtils');
-const AssetRegistry = require('@react-native/assets-registry/registry');
 
 type CustomSourceTransformer = (
   resolver: AssetSourceResolver,

packages/react-native/ReactNativeApi.d.ts

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<e62248f4d4932263a592c35ebf383e1a>>
+ * @generated SignedSource<<a2099475ab89899f0854f5f13f5d1af7>>
  *
  * This file was generated by scripts/js-api/build-types/index.js.
  */
@@ -151,6 +151,10 @@ declare const AnimatedScrollView_default: AnimatedComponentType<
 >
 declare const AppState: typeof AppState_default
 declare const AppState_default: AppStateImpl
+declare const AssetRegistry: {
+  getAssetByID(assetId: number): PackagerAsset
+  registerAsset(asset: PackagerAsset): number
+}
 declare const attachNativeEvent: typeof $$AnimatedImplementation.attachNativeEvent
 declare const BackHandler: typeof BackHandler_default
 declare const BackHandler_default: TBackHandler
@@ -1628,6 +1632,8 @@ declare interface ArrayLike_2<T> extends Iterable<T> {
   [indexer: number]: T
   readonly length: number
 }
+declare type AssetDestPathResolver = "android" | "generic"
+declare type AssetRegistry = typeof AssetRegistry
 declare type attachNativeEvent = typeof attachNativeEvent
 declare function attachNativeEventImpl(
   viewRef: any,
@@ -3469,6 +3475,17 @@ declare type OptionalVirtualizedSectionListProps<
 declare type OrientationChangeEvent = {
   readonly orientation: "landscape" | "portrait"
 }
+declare type PackagerAsset = {
+  readonly fileSystemLocation: string
+  readonly hash: string
+  readonly height: number | undefined
+  readonly httpServerLocation: string
+  readonly name: string
+  readonly resolver?: AssetDestPathResolver
+  readonly scales: Array<number>
+  readonly type: string
+  readonly width: number | undefined
+}
 declare type PanResponder = typeof PanResponder
 declare type PanResponderCallbacks = {
   readonly onMoveShouldSetPanResponder?: ActiveCallback
@@ -5915,6 +5932,8 @@ export {
   AppStateEvent, // 80f034c3
   AppStateStatus, // 447e5ef2
   Appearance, // 83e9641a
+  AssetDestPathResolver, // 59047424
+  AssetRegistry, // 6070bb45
   AutoCapitalize, // c0e857a0
   BackHandler, // f139fc69
   BackPressEventName, // 4620fb76
@@ -6046,6 +6065,7 @@ export {
   NativeUIEvent, // 44ac26ac
   Networking, // bbc5be42
   OpaqueColorValue, // 25f3fa5b
+  PackagerAsset, // d1c88cf4
   PanResponder, // f8f71cac
   PanResponderCallbacks, // 6d63e7be
   PanResponderGestureState, // 54baf558

packages/react-native/index.js

@@ -211,6 +211,9 @@ module.exports = {
   get AppState() {
     return require('./Libraries/AppState/AppState').default;
   },
+  get AssetRegistry() {
+    return require('./src/private/assets/AssetRegistry').AssetRegistry;
+  },
   get BackHandler() {
     return require('./Libraries/Utilities/BackHandler').default;
   },

packages/react-native/index.js.flow

@@ -276,6 +276,12 @@ export type {
 } from './Libraries/AppState/AppState';
 export {default as AppState} from './Libraries/AppState/AppState';
 
+export {AssetRegistry} from './src/private/assets/AssetRegistry';
+export type {
+  AssetDestPathResolver,
+  PackagerAsset,
+} from './src/private/assets/AssetRegistry';
+
 export type {BackPressEventName} from './Libraries/Utilities/BackHandler';
 export {default as BackHandler} from './Libraries/Utilities/BackHandler';