fix(cli): unnecessary subprocess call on every run

packages/aws-cdk/lib/cli/telemetry/library-version.ts

@@ -1,19 +1,23 @@
+import { createRequire } from 'module';
 import * as path from 'path';
 import * as fs from 'fs-extra';
 import type { IoHelper } from '../../api-private';
-import { run } from '../../private/tools';
 
 export async function getLibraryVersion(ioHelper: IoHelper): Promise<string | undefined> {
   try {
-    const { stdout } = await run([process.execPath, '-e', 'process.stdout.write(require.resolve("aws-cdk-lib"))']);
+    // Resolve from the app's directory rather than our own. The CLI is usually
+    // installed globally (or run via `npx`), so its own module paths don't contain
+    // the app's `aws-cdk-lib`.
+    const requireFromApp = createRequire(path.join(process.cwd(), 'index.js'));
+    const entryPoint = requireFromApp.resolve('aws-cdk-lib');
 
-    // stdout should be a file path but lets double check
-    if (!fs.existsSync(stdout)) {
+    // entryPoint should be a file path but lets double check
+    if (!fs.existsSync(entryPoint)) {
       await ioHelper.defaults.trace('Could not get CDK Library Version: require.resolve("aws-cdk-lib") did not return a file path');
       return;
     }
 
-    const pathToPackageJson = path.join(path.dirname(stdout), 'package.json');
+    const pathToPackageJson = path.join(path.dirname(entryPoint), 'package.json');
     const packageJson = fs.readJSONSync(pathToPackageJson);
     if (!packageJson.version) {
       await ioHelper.defaults.trace('Could not get CDK Library Version: package.json does not have version field');

packages/aws-cdk/test/cli/telemetry/library-version.test.ts

@@ -1,9 +1,15 @@
+import { createRequire } from 'module';
 import * as fs from 'fs-extra';
 import type { IoHelper } from '../../../lib/api-private';
 import { getLibraryVersion } from '../../../lib/cli/telemetry/library-version';
 import { run } from '../../../lib/private/tools';
 
-// Mock the subprocess tool's run()
+// Mock module resolution so we don't depend on this repo's own `aws-cdk-lib` install
+jest.mock('module', () => ({
+  createRequire: jest.fn(),
+}));
+
+// Mocked only so we can assert that we never reach for a subprocess
 jest.mock('@aws-cdk/private-tools/lib/subprocess', () => ({
   run: jest.fn(),
 }));
@@ -15,9 +21,17 @@ jest.mock('fs-extra', () => ({
 }));
 
 const mockRun = run as jest.MockedFunction<typeof run>;
+const mockCreateRequire = createRequire as jest.MockedFunction<typeof createRequire>;
 const mockExistsSync = fs.existsSync as jest.MockedFunction<typeof fs.existsSync>;
 const mockReadJSONSync = fs.readJSONSync as jest.MockedFunction<typeof fs.readJSONSync>;
 
+/**
+ * Make `createRequire()` return a `require` whose `resolve()` behaves as given
+ */
+function mockResolve(impl: () => string) {
+  mockCreateRequire.mockReturnValue({ resolve: jest.fn(impl) } as any);
+}
+
 describe('getLibraryVersion', () => {
   let mockIoHelper: IoHelper;
   let traceSpy: jest.Mock;
@@ -38,22 +52,43 @@ describe('getLibraryVersion', () => {
     const mockPackageJsonPath = '/path/to/node_modules/aws-cdk-lib/package.json';
     const expectedVersion = '2.100.0';
 
-    mockRun.mockResolvedValue({ stdout: mockLibPath, stderr: '' });
+    mockResolve(() => mockLibPath);
     mockExistsSync.mockReturnValue(true);
     mockReadJSONSync.mockReturnValue({ version: expectedVersion });
 
     const result = await getLibraryVersion(mockIoHelper);
 
     expect(result).toBe(expectedVersion);
-    expect(mockRun).toHaveBeenCalledWith([process.execPath, '-e', 'process.stdout.write(require.resolve("aws-cdk-lib"))']);
     expect(mockExistsSync).toHaveBeenCalledWith(mockLibPath);
     expect(mockReadJSONSync).toHaveBeenCalledWith(mockPackageJsonPath);
     expect(traceSpy).not.toHaveBeenCalled();
   });
 
+  test('resolves from the app directory, not from the CLI installation', async () => {
+    mockResolve(() => '/path/to/node_modules/aws-cdk-lib/index.js');
+    mockExistsSync.mockReturnValue(true);
+    mockReadJSONSync.mockReturnValue({ version: '2.100.0' });
+
+    await getLibraryVersion(mockIoHelper);
+
+    // Anchored inside the current working directory so that resolution walks up
+    // the app's `node_modules`, the same way the app itself would resolve it.
+    expect(mockCreateRequire).toHaveBeenCalledWith(expect.stringContaining(process.cwd()));
+  });
+
+  test('resolves in-process, without spawning a subprocess', async () => {
+    mockResolve(() => '/path/to/node_modules/aws-cdk-lib/index.js');
+    mockExistsSync.mockReturnValue(true);
+    mockReadJSONSync.mockReturnValue({ version: '2.100.0' });
+
+    await getLibraryVersion(mockIoHelper);
+
+    expect(mockRun).not.toHaveBeenCalled();
+  });
+
   test('returns undefined and logs trace when resolved path does not exist', async () => {
     const mockLibPath = '/nonexistent/path/to/aws-cdk-lib/index.js';
-    mockRun.mockResolvedValue({ stdout: mockLibPath, stderr: '' });
+    mockResolve(() => mockLibPath);
     mockExistsSync.mockReturnValue(false);
 
     const result = await getLibraryVersion(mockIoHelper);
@@ -66,21 +101,23 @@ describe('getLibraryVersion', () => {
     );
   });
 
-  test('returns undefined and logs trace when run() throws', async () => {
-    const runError = new Error('spawn ENOENT');
-    mockRun.mockRejectedValue(runError);
+  test('returns undefined and logs trace when aws-cdk-lib cannot be resolved', async () => {
+    const resolveError = new Error("Cannot find module 'aws-cdk-lib'");
+    mockResolve(() => {
+      throw resolveError;
+    });
 
     const result = await getLibraryVersion(mockIoHelper);
 
     expect(result).toBeUndefined();
     expect(mockExistsSync).not.toHaveBeenCalled();
     expect(mockReadJSONSync).not.toHaveBeenCalled();
-    expect(traceSpy).toHaveBeenCalledWith(`Could not get CDK Library Version: ${runError}`);
+    expect(traceSpy).toHaveBeenCalledWith(`Could not get CDK Library Version: ${resolveError}`);
   });
 
   test('handles package.json without version field', async () => {
     const mockLibPath = '/path/to/node_modules/aws-cdk-lib/index.js';
-    mockRun.mockResolvedValue({ stdout: mockLibPath, stderr: '' });
+    mockResolve(() => mockLibPath);
     mockExistsSync.mockReturnValue(true);
     mockReadJSONSync.mockReturnValue({ name: 'aws-cdk-lib' });