fix(workspaces): use shell option on Windows for package manager commands

Add preferLocal and shell options to execa calls to properly resolve package manager executables on Windows, especially when Bun is installed via the bash installer. This fixes issue #11035 where "no package.json found" error occurs during create-turbo on Windows with Bun.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: anthonyshew

packages/turbo-workspaces/__tests__/index.test.ts

@@ -2,8 +2,8 @@ import path from "node:path";
 import execa from "execa";
 import * as turboUtils from "@turbo/utils";
 import { setupTestFixtures } from "@turbo/test-utils";
-import { describe, it, expect, jest } from "@jest/globals";
-import { getWorkspaceDetails, convert } from "../src";
+import { describe, it, expect, jest, beforeEach } from "@jest/globals";
+import { getWorkspaceDetails, convert, install } from "../src";
 import { generateConvertMatrix } from "./test-utils";
 
 jest.mock("execa", () => jest.fn());
@@ -13,6 +13,108 @@ describe("Node entrypoint", () => {
     directory: path.join(__dirname, "../"),
   });
 
+  beforeEach(() => {
+    jest.clearAllMocks();
+    (execa as jest.MockedFunction<typeof execa>).mockResolvedValue({
+      stdout: "",
+      stderr: "",
+      exitCode: 0,
+      command: "",
+      failed: false,
+      timedOut: false,
+      isCanceled: false,
+      killed: false,
+    } as any);
+  });
+
+  describe("install", () => {
+    it("should use shell option on Windows for all package managers", async () => {
+      const originalPlatform = process.platform;
+      Object.defineProperty(process, "platform", {
+        value: "win32",
+      });
+
+      const { root } = useFixture({
+        fixture: `./bun/monorepo`,
+      });
+
+      const mockProject = {
+        name: "test-project",
+        description: undefined,
+        packageManager: "bun" as const,
+        paths: {
+          root,
+          packageJson: path.join(root, "package.json"),
+          lockfile: path.join(root, "bun.lockb"),
+          nodeModules: path.join(root, "node_modules"),
+        },
+        workspaceData: {
+          globs: ["apps/*", "packages/*"],
+          workspaces: [],
+        },
+      };
+
+      await install({
+        project: mockProject,
+        to: { name: "bun", version: "1.0.1" },
+        options: { dry: false },
+      });
+
+      expect(execa).toHaveBeenCalledWith("bun", ["install"], {
+        cwd: root,
+        preferLocal: true,
+        shell: true,
+      });
+
+      Object.defineProperty(process, "platform", {
+        value: originalPlatform,
+      });
+    });
+
+    it("should not use shell option on non-Windows platforms", async () => {
+      const originalPlatform = process.platform;
+      Object.defineProperty(process, "platform", {
+        value: "darwin",
+      });
+
+      const { root } = useFixture({
+        fixture: `./bun/monorepo`,
+      });
+
+      const mockProject = {
+        name: "test-project",
+        description: undefined,
+        packageManager: "bun" as const,
+        paths: {
+          root,
+          packageJson: path.join(root, "package.json"),
+          lockfile: path.join(root, "bun.lockb"),
+          nodeModules: path.join(root, "node_modules"),
+        },
+        workspaceData: {
+          globs: ["apps/*", "packages/*"],
+          workspaces: [],
+        },
+      };
+
+      await install({
+        project: mockProject,
+        to: { name: "bun", version: "1.0.1" },
+        options: { dry: false },
+      });
+
+      expect(execa).toHaveBeenCalledWith("bun", ["install"], {
+        cwd: root,
+        preferLocal: true,
+        shell: false,
+      });
+
+      Object.defineProperty(process, "platform", {
+        value: originalPlatform,
+      });
+    });
+  });
+
   describe("convert", () => {
     it.each(generateConvertMatrix())(
       "detects $fixtureType project using $fixtureManager and converts to $toManager (interactive=$interactive dry=$dry install=$install)",

packages/turbo-workspaces/src/install.ts

@@ -127,6 +127,8 @@ export async function install(args: InstallArgs) {
     try {
       await execa(packageManager.command, packageManager.installArgs, {
         cwd: args.project.paths.root,
+        preferLocal: true,
+        shell: process.platform === "win32",
       });
       if (spinner) {
         spinner.stop();

packages/turbo-workspaces/src/managers/pnpm.ts

@@ -240,6 +240,8 @@ async function convertLock(args: ConvertArgs): Promise<void> {
         await execa(PACKAGE_MANAGER_DETAILS.name, ["import"], {
           stdio: "ignore",
           cwd: project.paths.root,
+          preferLocal: true,
+          shell: process.platform === "win32",
         });
       } catch (err) {
         // do nothing

packages/turbo-workspaces/src/utils.ts

@@ -276,6 +276,8 @@ async function bunLockToYarnLock({
       const { stdout } = await execa("bun", ["bun.lockb"], {
         stdin: "ignore",
         cwd: project.paths.root,
+        preferLocal: true,
+        shell: process.platform === "win32",
       });
       // write the yarn lockfile
       await writeFile(path.join(project.paths.root, "yarn.lock"), stdout);