🐛 Resolve Vite dependencies from their parent package

src/entries/vite-plugin.spec.ts

@@ -0,0 +1,51 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const mocks = vi.hoisted(() => ({
+  cpSync: vi.fn(),
+  createRequire: vi.fn(),
+  existsSync: vi.fn(),
+  mkdirSync: vi.fn(),
+  readFileSync: vi.fn(),
+}));
+
+vi.mock('node:fs', () => ({
+  cpSync: mocks.cpSync,
+  existsSync: mocks.existsSync,
+  mkdirSync: mocks.mkdirSync,
+  readFileSync: mocks.readFileSync,
+}));
+vi.mock('node:module', () => ({ createRequire: mocks.createRequire }));
+
+import { datadogVitePlugin } from './vite-plugin';
+
+describe('datadogVitePlugin', () => {
+  beforeEach(() => {
+    vi.resetAllMocks();
+  });
+
+  it('resolves transitive dependencies from their parent package', () => {
+    const rootResolve = vi.fn((pkg: string) => {
+      if (pkg === 'dd-trace') return '/packages/dd-trace/index.js';
+      if (pkg === '@datadog/electron-sdk') return '/packages/electron-sdk/index.js';
+      throw new Error(`Cannot resolve ${pkg}`);
+    });
+    const ddTraceResolve = vi.fn(() => '/packages/nested-package/index.js');
+
+    mocks.createRequire.mockImplementation((path: string) => ({
+      resolve: path === '/packages/dd-trace/package.json' ? ddTraceResolve : rootResolve,
+    }));
+    mocks.existsSync.mockImplementation((path: string) =>
+      path.startsWith('/packages/') ? path.endsWith('/package.json') : false
+    );
+    mocks.readFileSync.mockImplementation((path: string) =>
+      JSON.stringify({ dependencies: path === '/packages/dd-trace/package.json' ? { 'nested-package': '1.0.0' } : {} })
+    );
+
+    datadogVitePlugin().writeBundle?.({ dir: '/output' });
+
+    expect(ddTraceResolve).toHaveBeenCalledWith('nested-package');
+    expect(mocks.cpSync).toHaveBeenCalledWith('/packages/nested-package', '/output/node_modules/nested-package', {
+      recursive: true,
+    });
+  });
+});

src/entries/vite-plugin.ts

@@ -77,13 +77,13 @@ export function datadogVitePlugin(): VitePlugin {
       const destModules = join(outDir, 'node_modules');
       const visited = new Set<string>();
 
-      function copyPackageTree(pkg: string): void {
+      function copyPackageTree(pkg: string, resolveFrom = _require): void {
         if (visited.has(pkg)) return;
         visited.add(pkg);
 
         try {
           // Resolve the package's main entry, then walk up to find the root
-          const entryPath = _require.resolve(pkg);
+          const entryPath = resolveFrom.resolve(pkg);
           let pkgDir = dirname(entryPath);
           while (pkgDir !== dirname(pkgDir) && !existsSync(join(pkgDir, 'package.json'))) {
             pkgDir = dirname(pkgDir);
@@ -99,8 +99,9 @@ export function datadogVitePlugin(): VitePlugin {
           const pkgJson = JSON.parse(readFileSync(join(pkgDir, 'package.json'), 'utf8')) as {
             dependencies?: Record<string, string>;
           };
+          const packageRequire = createRequire(join(pkgDir, 'package.json'));
           for (const dep of Object.keys(pkgJson.dependencies ?? {})) {
-            copyPackageTree(dep);
+            copyPackageTree(dep, packageRequire);
           }
         } catch {
           console.warn(`[datadog] Failed to copy package '${pkg}' to build output`);