Restrict React DOM imports from Server Components

Adds a separate entry point for the react-dom package when it's
accessed from a Server Component environment, using the "react-server"
export condition.

When you're inside a Server Component module, you won't be able to
import client-only APIs like useState. This applies to almost all React
DOM exports, except for Float ones like preload.

packages/react-dom/npm/react-dom.shared-subset.js

@@ -0,0 +1,7 @@
+'use strict';
+
+if (process.env.NODE_ENV === 'production') {
+  module.exports = require('./cjs/react-dom.shared-subset.production.min.js');
+} else {
+  module.exports = require('./cjs/react-dom.shared-subset.development.js');
+}

packages/react-dom/package.json

@@ -46,7 +46,10 @@
     "umd/"
   ],
   "exports": {
-    ".": "./index.js",
+    ".": {
+      "react-server": "./react-dom.shared-subset.js",
+      "default": "./index.js"
+    },
     "./client": "./client.js",
     "./server": {
       "workerd": "./server.edge.js",

packages/react-dom/src/ReactDOMSharedSubset.js

@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+// This is the subset of APIs that can be accessed from Server Component modules
+export {default as __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED} from './ReactDOMSharedInternals';
+export {
+  prefetchDNS,
+  preconnect,
+  preload,
+  preloadModule,
+  preinit,
+  preinitModule,
+  version,
+} from './client/ReactDOM';

scripts/rollup/bundles.js

@@ -165,6 +165,18 @@ const bundles = [
     externals: ['react'],
   },
 
+  /******* React DOM Shared Subset *******/
+  {
+    bundleTypes: [NODE_DEV, NODE_PROD],
+    moduleType: RENDERER,
+    entry: 'react-dom/src/ReactDOMSharedSubset.js',
+    name: 'react-dom.shared-subset',
+    global: 'ReactDOM',
+    minifyWithProdErrorCodes: false,
+    wrapWithModuleBoundaries: false,
+    externals: ['react'],
+  },
+
   /******* Test Utils *******/
   {
     moduleType: RENDERER_UTILS,