fix(core): hide already-installed nx packages from suggestion list during nx import (#34227)

## Current Behavior
If something is in `package.json#dependencies`, we still suggest it to
be `nx add`-ed during `nx import`

## Expected Behavior
If a plugin is already installed, we don't suggest it anymore

(cherry picked from commit f89ccb0)

Author: MaxKless

packages/nx/src/command-line/import/import.ts

@@ -9,6 +9,8 @@ import { output } from '../../utils/output';
 const createSpinner = require('ora');
 import { detectPlugins } from '../init/init-v2';
 import { readNxJson } from '../../config/nx-json';
+import { readJsonFile } from '../../utils/fileutils';
+import { PackageJson } from '../../utils/package-json';
 import { workspaceRoot } from '../../utils/workspace-root';
 import {
   addPackagePathToWorkspaces,
@@ -263,8 +265,15 @@ export async function importHandler(options: ImportOptions) {
 
   resetWorkspaceContext();
 
+  let packageJson: PackageJson | null;
+  try {
+    packageJson = readJsonFile<PackageJson>('package.json');
+  } catch {
+    packageJson = null;
+  }
   const { plugins, updatePackageScripts } = await detectPlugins(
     nxJson,
+    packageJson,
     options.interactive,
     true
   );

packages/nx/src/command-line/init/init-v2.spec.ts

@@ -0,0 +1,78 @@
+import { detectPlugins } from './init-v2';
+
+// Mock dependencies
+jest.mock('fs', () => ({
+  ...jest.requireActual('fs'),
+  existsSync: jest.fn((path: string) => {
+    if (path === 'package.json') return true;
+    return false;
+  }),
+}));
+
+jest.mock('../../utils/fileutils', () => ({
+  readJsonFile: jest.fn(),
+  fileExists: jest.fn(() => false),
+}));
+
+import { readJsonFile } from '../../utils/fileutils';
+const mockReadJsonFile = readJsonFile as jest.Mock;
+
+jest.mock('../../utils/workspace-context', () => ({
+  globWithWorkspaceContextSync: jest.fn(() => []),
+}));
+
+jest.mock('../../utils/output', () => ({
+  output: { log: jest.fn() },
+}));
+
+describe('detectPlugins', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('should not suggest a plugin that is already installed as an npm dependency', async () => {
+    const packageJson = {
+      name: 'test',
+      version: '1.0.0',
+      dependencies: { vite: '^5.0.0' },
+      devDependencies: { '@nx/vite': '19.0.0' },
+    };
+    mockReadJsonFile.mockReturnValue(packageJson);
+
+    const result = await detectPlugins({ plugins: [] }, packageJson, false);
+
+    expect(result.plugins).not.toContain('@nx/vite');
+  });
+
+  it('should suggest a plugin when the tool is installed but the nx plugin is not', async () => {
+    const packageJson = {
+      name: 'test',
+      version: '1.0.0',
+      dependencies: { vite: '^5.0.0' },
+      devDependencies: {},
+    };
+    mockReadJsonFile.mockReturnValue(packageJson);
+
+    const result = await detectPlugins({ plugins: [] }, packageJson, false);
+
+    expect(result.plugins).toContain('@nx/vite');
+  });
+
+  it('should not suggest a plugin already listed in nx.json plugins', async () => {
+    const packageJson = {
+      name: 'test',
+      version: '1.0.0',
+      dependencies: { vite: '^5.0.0' },
+      devDependencies: {},
+    };
+    mockReadJsonFile.mockReturnValue(packageJson);
+
+    const result = await detectPlugins(
+      { plugins: ['@nx/vite'] },
+      packageJson,
+      false
+    );
+
+    expect(result.plugins).not.toContain('@nx/vite');
+  });
+});

packages/nx/src/command-line/init/init-v2.ts

@@ -183,7 +183,7 @@ async function initHandlerImpl(options: InitArgs): Promise<void> {
       updatePackageScripts = true;
     } else {
       const { plugins: _plugins, updatePackageScripts: _updatePackageScripts } =
-        await detectPlugins(nxJson, options.interactive);
+        await detectPlugins(nxJson, packageJson, options.interactive);
       plugins = _plugins;
       updatePackageScripts = _updatePackageScripts;
     }
@@ -273,6 +273,7 @@ const npmPackageToPluginMap: Record<string, `@nx/${string}`> = {
 
 export async function detectPlugins(
   nxJson: NxJsonConfiguration,
+  packageJson: PackageJson | null,
   interactive: boolean,
   includeAngularCli?: boolean
 ): Promise<{
@@ -290,6 +291,17 @@ export async function detectPlugins(
     })
   );
 
+  // Also treat already-installed @nx/* and @nrwl/* packages as current plugins
+  const rootDeps = {
+    ...packageJson?.dependencies,
+    ...packageJson?.devDependencies,
+  };
+  for (const dep of Object.keys(rootDeps)) {
+    if (dep.startsWith('@nx/') || dep.startsWith('@nrwl/')) {
+      currentPlugins.add(getPackageNameFromImportPath(dep));
+    }
+  }
+
   const detectedPlugins = new Set<string>();
   for (const file of files) {
     if (!existsSync(file)) continue;