chore: fix rit and e2e

Author: mainframev

tools/react-integration-tester/src/__tests__/cli.e2e.test.ts

@@ -105,7 +105,11 @@ describe('rit CLI e2e', () => {
     expect(runCmd.cwd).toEqual(expect.stringContaining(join(fs.tempDir, 'tmp/rit/react-18/proj-react-18')));
 
     // no project folder exists as it was cleanuped
-    expect(readdirSync(join(fs.tempDir, 'tmp/rit/react-18/'))).toEqual(['package.json']);
+    expect(readdirSync(join(fs.tempDir, 'tmp/rit/react-18/')).sort()).toEqual([
+      '.yarnrc.yml',
+      'package.json',
+      'yarn.lock',
+    ]);
   });
 
   test('--install-deps installs into react root (no project scaffolding)', () => {

tools/react-integration-tester/src/setup.ts

@@ -125,6 +125,23 @@ function renderTemplateToFile(templateFilePath: string, data: Record<string, unk
  * Writes only when the file does not exist or dependencies actually change (to avoid race issues on CI).
  * Returned value indicates whether a write occurred.
  */
+function ensureWorkspaceIsolation(reactRootPath: string) {
+  // Create an empty yarn.lock so Yarn 4 treats this directory as a standalone
+  // project root instead of traversing up into the parent monorepo workspace.
+  const yarnLockPath = join(reactRootPath, 'yarn.lock');
+  if (!existsSync(yarnLockPath)) {
+    writeFileSync(yarnLockPath, '');
+  }
+
+  // Create a minimal .yarnrc.yml so that Yarn uses node-modules linker and
+  // does not inherit the parent workspace's yarnPath (which is a relative path
+  // that would not resolve correctly from the tmp directory).
+  const yarnrcPath = join(reactRootPath, '.yarnrc.yml');
+  if (!existsSync(yarnrcPath)) {
+    writeFileSync(yarnrcPath, 'nodeLinker: node-modules\n');
+  }
+}
+
 function upsertReactRootPackageJson(params: {
   reactRootPath: string;
   react: ReactVersion;
@@ -133,6 +150,7 @@ function upsertReactRootPackageJson(params: {
 }): { wrote: boolean; pkgPath: string } {
   const { reactRootPath, react, dependencies, logger } = params;
   mkdirSync(reactRootPath, { recursive: true });
+  ensureWorkspaceIsolation(reactRootPath);
   const reactRootPkgPath = join(reactRootPath, 'package.json');
 
   const basePkg: PackageJson = {