From d54f775362c0ebc3f348b106677c9c15305e77ef Mon Sep 17 00:00:00 2001
From: Valentin Palkovic <valentin@chromatic.com>
Date: Fri, 1 Nov 2024 12:43:11 +0100
Subject: [PATCH] Merge pull request #29444 from
 sentience/fix-nextjs-react-paths-in-monorepo

Next.js: Fix bundled react and react-dom in monorepos

(cherry picked from commit 6c829c545ed0d28b0b9edb88713db0b21a4eb28c)
---
 code/frameworks/nextjs/src/config/webpack.ts |  8 ++--
 code/frameworks/nextjs/src/utils.ts          | 42 +++++++++++++++-----
 2 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/code/frameworks/nextjs/src/config/webpack.ts b/code/frameworks/nextjs/src/config/webpack.ts
index a0ea2d47bded..76edac25c81c 100644
--- a/code/frameworks/nextjs/src/config/webpack.ts
+++ b/code/frameworks/nextjs/src/config/webpack.ts
@@ -36,16 +36,16 @@ export const configureConfig = async ({
     addScopedAlias(baseConfig, 'react', 'next/dist/compiled/react');
   }
   if (tryResolve('next/dist/compiled/react-dom/cjs/react-dom-test-utils.production.js')) {
-    setAlias(
+    addScopedAlias(
       baseConfig,
       'react-dom/test-utils',
       'next/dist/compiled/react-dom/cjs/react-dom-test-utils.production.js'
     );
   }
   if (tryResolve('next/dist/compiled/react-dom')) {
-    setAlias(baseConfig, 'react-dom$', 'next/dist/compiled/react-dom');
-    setAlias(baseConfig, 'react-dom/client', 'next/dist/compiled/react-dom/client');
-    setAlias(baseConfig, 'react-dom/server', 'next/dist/compiled/react-dom/server');
+    addScopedAlias(baseConfig, 'react-dom$', 'next/dist/compiled/react-dom');
+    addScopedAlias(baseConfig, 'react-dom/client', 'next/dist/compiled/react-dom/client');
+    addScopedAlias(baseConfig, 'react-dom/server', 'next/dist/compiled/react-dom/server');
   }
 
   setupRuntimeConfig(baseConfig, nextConfig);
diff --git a/code/frameworks/nextjs/src/utils.ts b/code/frameworks/nextjs/src/utils.ts
index 198917513166..82f15d088f59 100644
--- a/code/frameworks/nextjs/src/utils.ts
+++ b/code/frameworks/nextjs/src/utils.ts
@@ -51,18 +51,36 @@ export const addScopedAlias = (baseConfig: WebpackConfig, name: string, alias?:
 };
 
 /**
- * @example // before main script path truncation require.resolve('styled-jsx') ===
- * '/some/path/node_modules/styled-jsx/index.js // after main script path truncation
+ * @example
+ *
+ * ```
+ * // before main script path truncation
+ * require.resolve('styled-jsx') === '/some/path/node_modules/styled-jsx/index.js
+ * // after main script path truncation
  * scopedResolve('styled-jsx') === '/some/path/node_modules/styled-jsx'
+ * ```
+ *
+ * @example
+ *
+ * ```
+ * // referencing a named export of a package
+ * scopedResolve('next/dist/compiled/react-dom/client') ===
+ *   // returns the path to the package export without the script filename
+ *   '/some/path/node_modules/next/dist/compiled/react-dom/client';
+ *
+ * // referencing a specific file within a CJS package
+ * scopedResolve('next/dist/compiled/react-dom/cjs/react-dom-test-utils.production.js') ===
+ *   // returns the path to the physical file, including the script filename
+ *   '/some/path/node_modules/next/dist/compiled/react-dom/cjs/react-dom-test-utils.production.js';
+ * ```
  *
- * @param id The module id
- * @returns A path to the module id scoped to the project folder without the main script path at the
- *   end
+ * @param id The module id or script file to resolve
+ * @returns An absolute path to the specified module id or script file scoped to the project folder
  * @summary
  * This is to help the addon in development.
  * Without it, the addon resolves packages in its node_modules instead of the example's node_modules.
  * Because require.resolve will also include the main script as part of the path, this function strips
- * that to just include the path to the module folder
+ * that to just include the path to the module folder when the id provided is a package or named export.
  */
 export const scopedResolve = (id: string): string => {
   let scopedModulePath;
@@ -74,9 +92,15 @@ export const scopedResolve = (id: string): string => {
     scopedModulePath = require.resolve(id);
   }
 
-  const moduleFolderStrPosition = scopedModulePath.lastIndexOf(
-    id.replace(/\//g /* all '/' occurances */, sep)
-  );
+  const idWithNativePathSep = id.replace(/\//g /* all '/' occurrences */, sep);
+
+  // If the id referenced the file specifically, return the full module path & filename
+  if (scopedModulePath.endsWith(idWithNativePathSep)) {
+    return scopedModulePath;
+  }
+
+  // Otherwise, return just the path to the module folder or named export
+  const moduleFolderStrPosition = scopedModulePath.lastIndexOf(idWithNativePathSep);
   const beginningOfMainScriptPath = moduleFolderStrPosition + id.length;
   return scopedModulePath.substring(0, beginningOfMainScriptPath);
 };