fix(workspaces): Use shell option on Windows in execa call (#11108)

## Summary

Addresses #11035 by adding `preferLocal` and `shell` options to `execa`
calls for package manager commands. This resolves the "no package.json
found" error that occurs when using Bun installed via bash installer on
Windows.

When Bun is installed via `curl -fsSL https://bun.sh/install | bash`,
it's placed in a Unix-style PATH that Node.js can't access without shell
context. Using `shell: true` on Windows allows the shell to resolve
these commands properly.

## Test Results

CI and canarying to be verified on Windows.

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);