fix: use native spawn sync on bun

.changeset/lefthook-spawn-adapter.md

@@ -0,0 +1,5 @@
+---
+"ultracite": patch
+---
+
+Run `lefthook install` during `ultracite init` through the same spawn adapter as every other tool invocation instead of `execSync`, so it no longer goes through a shell and gets the same Windows command resolution as `husky`, the linters, and editor extension installs.

packages/cli/__tests__/editor-config.test.ts

@@ -9,10 +9,6 @@ mock.module("node:fs/promises", () => ({
   writeFile: mock(() => Promise.resolve()),
 }));
 
-mock.module("node:child_process", () => ({
-  spawnSync: mock(() => ({ status: 0 })),
-}));
-
 describe("createEditorConfig", () => {
   describe("invalid editor", () => {
     test("throws error for invalid editor id", () => {

packages/cli/__tests__/husky.test.ts

@@ -6,11 +6,6 @@ import { husky } from "../src/integrations/husky";
 
 const npmPm: PackageManager = { command: "npm", name: "npm" };
 
-mock.module("node:child_process", () => ({
-  execSync: mock(() => ""),
-  spawnSync: mock(() => ({ status: 0 })),
-}));
-
 mock.module("node:fs/promises", () => ({
   access: mock(() => Promise.reject(new Error("ENOENT"))),
   mkdir: mock(() => Promise.resolve()),

packages/cli/__tests__/index.test.ts

@@ -37,11 +37,6 @@ mock.module("node:fs/promises", () => ({
   writeFile: mock(() => Promise.resolve()),
 }));
 
-mock.module("node:child_process", () => ({
-  execSync: mock(() => ""),
-  spawnSync: mock(() => ({ status: 0, stdout: "1.0.0" })),
-}));
-
 mock.module("node:fs", () => ({
   existsSync: mock(() => false),
 }));

packages/cli/__tests__/initialize.test.ts

@@ -37,11 +37,6 @@ mock.module("node:fs/promises", () => ({
   writeFile: mock(() => Promise.resolve()),
 }));
 
-mock.module("node:child_process", () => ({
-  execSync: mock(() => ""),
-  spawnSync: mock(() => ({ status: 0 })),
-}));
-
 mock.module("../src/spawn-sync", () => ({
   spawnSync: mock(() => ({ status: 0, stdout: "[]" })),
 }));
@@ -2425,11 +2420,6 @@ describe("helper functions", () => {
         writeFile: mockWriteFile,
       }));
 
-      mock.module("node:child_process", () => ({
-        execSync: mock(() => ""),
-        spawnSync: mock(() => ({ status: 0 })),
-      }));
-
       mock.module("@clack/prompts", () => ({
         spinner: mock(() => ({
           message: mock(noop),
@@ -2481,12 +2471,12 @@ describe("helper functions", () => {
         writeFile: mockWriteFile,
       }));
 
-      // Mock extension install to throw error
-      mock.module("node:child_process", () => ({
-        execSync: mock(() => ""),
-        spawnSync: mock(() => {
-          throw new Error("Extension install failed");
-        }),
+      // Mock extension install failing to spawn
+      mock.module("../src/spawn-sync", () => ({
+        spawnSync: mock(() => ({
+          error: new Error("Extension install failed"),
+          status: null,
+        })),
       }));
 
       mock.module("@clack/prompts", () => ({
@@ -2998,11 +2988,6 @@ describe("helper functions", () => {
         writeFile: mockWriteFile,
       }));
 
-      mock.module("node:child_process", () => ({
-        execSync: mock(() => ""),
-        spawnSync: mock(() => ({ status: 0 })),
-      }));
-
       mock.module("@clack/prompts", () => ({
         spinner: mock(() => ({
           message: mock(noop),
@@ -3038,11 +3023,6 @@ describe("helper functions", () => {
         writeFile: mockWriteFile,
       }));
 
-      mock.module("node:child_process", () => ({
-        execSync: mock(() => ""),
-        spawnSync: mock(() => ({ status: 0 })),
-      }));
-
       mock.module("@clack/prompts", () => ({
         spinner: mock(() => ({
           message: mock(noop),

packages/cli/__tests__/lefthook.test.ts

@@ -6,8 +6,7 @@ import { lefthook } from "../src/integrations/lefthook";
 
 const npmPm: PackageManager = { command: "npm", name: "npm" };
 
-mock.module("node:child_process", () => ({
-  execSync: mock(() => ""),
+mock.module("../src/spawn-sync", () => ({
   spawnSync: mock(() => ({ status: 0 })),
 }));
 
@@ -75,12 +74,6 @@ describe("lefthook", () => {
   describe("install", () => {
     test("installs lefthook dependency", async () => {
       const mockAddDep = mock(() => Promise.resolve());
-      const mockExecSync = mock(() => "");
-
-      mock.module("node:child_process", () => ({
-        execSync: mockExecSync,
-        spawnSync: mock(() => ({ status: 0 })),
-      }));
 
       mock.module("node:fs/promises", () => ({
         access: mock(() => Promise.resolve()),
@@ -112,10 +105,9 @@ describe("lefthook", () => {
     });
 
     test("runs lefthook install command", async () => {
-      const mockExecSync = mock(() => "");
-      mock.module("node:child_process", () => ({
-        execSync: mockExecSync,
-        spawnSync: mock(() => ({ status: 0 })),
+      const mockSpawnSync = mock(() => ({ status: 0 }));
+      mock.module("../src/spawn-sync", () => ({
+        spawnSync: mockSpawnSync,
       }));
 
       mock.module("node:fs/promises", () => ({
@@ -144,7 +136,13 @@ describe("lefthook", () => {
 
       await lefthook.install(npmPm);
 
-      expect(mockExecSync).toHaveBeenCalled();
+      expect(mockSpawnSync).toHaveBeenCalledWith(
+        "npx",
+        ["lefthook", "install"],
+        {
+          stdio: "pipe",
+        }
+      );
     });
 
     test("adds prepare script to package.json", async () => {
@@ -179,11 +177,6 @@ describe("lefthook", () => {
         removeDependency: mock(() => Promise.resolve()),
       }));
 
-      mock.module("node:child_process", () => ({
-        execSync: mock(() => ""),
-        spawnSync: mock(() => ({ status: 0 })),
-      }));
-
       await lefthook.install(npmPm);
 
       expect(mockWriteFile).toHaveBeenCalled();

packages/cli/__tests__/oxlint-config.test.ts

@@ -64,9 +64,9 @@ const JS_PLUGINS = [
  * text-parsing version of this helper silently return nothing.
  */
 const getOxlintRulesForPlugins = (plugins: string[]): string[] => {
-  // Bun.spawnSync rather than node:child_process — several test files
-  // install module-level mocks of node:child_process that leak across
-  // files when the suite runs without --isolate.
+  // Bun.spawnSync rather than the ../src/spawn-sync adapter — several test
+  // files install module-level mocks of that adapter which leak across files
+  // when the suite runs without --isolate.
   //
   // Run from the system temp dir with an absolute binary path so oxlint
   // does not walk up and auto-discover the repo's `oxlint.config.ts`. The

packages/cli/__tests__/preload.ts

@@ -6,17 +6,6 @@ import {
 
 import { spawnSync as _realSpawnSync } from "../src/spawn-sync";
 
-// Eagerly link nypm (and its transitive tinyexec, which does
-// `import { spawn, spawnSync } from "node:child_process"`) against the real
-// node:child_process before any test installs a partial mock of it. Several
-// tests mock node:child_process with only a subset of exports (e.g. just
-// spawnSync); because Bun's mock.module is global, whichever partial mock is
-// active when tinyexec first links determines whether `spawn` resolves. Test
-// file order differs between platforms, so on CI (Linux) a spawn-less mock can
-// be active first, throwing "Export named 'spawn' not found in module
-// 'node:child_process'". Linking it here makes resolution order-independent.
-import "nypm";
-
 // Typed globals for the real implementations captured below, so consumers
 // (mock-fs.ts, spawn-sync.test.ts) can read them without type assertions.
 declare global {

packages/cli/__tests__/spawn-sync.test.ts

@@ -24,19 +24,35 @@ describe("spawnSync", () => {
     expect(result.status).toBe(3);
   });
 
-  test("maps a spawn failure to an error with a null status", () => {
+  test("maps a missing command according to the host platform", () => {
     const result = spawnSync("definitely-not-a-real-command", []);
 
+    if (process.platform === "win32") {
+      // execa can't resolve the command, so it runs it through cmd.exe, which
+      // exits non-zero with "is not recognized" — the process did spawn.
+      expect(result.error).toBeUndefined();
+      expect(result.status).not.toBe(0);
+      expect(result.status).not.toBeNull();
+      return;
+    }
+
     expect(result.error).toBeInstanceOf(Error);
     expect(result.status).toBeNull();
   });
 
-  test("maps a signal kill to a null status with the signal set", () => {
+  test("maps process termination according to the host platform", () => {
     const result = spawnSync(node, [
       "-e",
       "process.kill(process.pid, 'SIGKILL')",
     ]);
 
+    if (process.platform === "win32") {
+      // Windows does not expose POSIX signals through child_process.
+      expect(result.status).not.toBe(0);
+      expect(result.signal).toBeUndefined();
+      return;
+    }
+
     expect(result.status).toBeNull();
     expect(result.signal).toBe("SIGKILL");
   });
@@ -55,12 +71,25 @@ describe("spawnSync", () => {
     expect(result.stdout?.trim()).toBe(tricky);
   });
 
-  test("does not capture stdout when stdio is inherit", () => {
+  test("does not capture stdout when stdio is ignore", () => {
     const result = spawnSync(node, ["-e", "process.exit(0)"], {
       stdio: "ignore",
     });
 
     expect(result.status).toBe(0);
     expect(result.stdout).toBeUndefined();
   });
+
+  // Callers such as `skills list --json` don't set maxBuffer and rely on
+  // execa's 100 MB default rather than Node's 1 MiB.
+  test("captures more than Node's 1 MiB default maxBuffer", () => {
+    const result = spawnSync(node, [
+      "-e",
+      "process.stdout.write('x'.repeat(2 * 1024 * 1024))",
+    ]);
+
+    expect(result.error).toBeUndefined();
+    expect(result.status).toBe(0);
+    expect(result.stdout?.length).toBe(2 * 1024 * 1024);
+  });
 });

packages/cli/__tests__/vscode.test.ts

@@ -2,11 +2,6 @@ import { beforeEach, describe, expect, mock, test } from "bun:test";
 
 import { createEditorConfig } from "../src/editor-config";
 
-mock.module("node:child_process", () => ({
-  execSync: mock(() => ""),
-  spawnSync: mock(() => ({ status: 0 })),
-}));
-
 mock.module("node:fs/promises", () => ({
   access: mock(() => Promise.reject(new Error("ENOENT"))),
   mkdir: mock(() => Promise.resolve()),

packages/cli/src/integrations/lefthook.ts

@@ -1,11 +1,11 @@
-import { execSync } from "node:child_process";
 import { readFile } from "node:fs/promises";
 
 import { log } from "@clack/prompts";
 import { addDevDependency, dlxCommand } from "nypm";
 import type { PackageManager, PackageManagerName } from "nypm";
 
 import { getRootInstallOptions } from "../package-manager";
+import { spawnSync } from "../spawn-sync";
 import { exists, updatePackageJson, writeProjectFile } from "../utils";
 
 // The top-level pre-commit hook and its indented block (including blank
@@ -59,18 +59,18 @@ export const lefthook = {
       },
     });
 
-    const installCommand = dlxCommand(packageManager.name, "lefthook", {
+    // dlxCommand returns a full command line, e.g. "npx lefthook install" —
+    // split it so spawn gets a real binary and never a shell.
+    const [command, ...args] = dlxCommand(packageManager.name, "lefthook", {
       args: ["install"],
       short: packageManager.name === "npm",
-    });
+    }).split(" ");
 
-    try {
-      execSync(installCommand, { stdio: "pipe" });
-    } catch {
-      // lefthook install fails with exit code 128 when not in a git repository.
-      // The dependency and prepare script are still set up, so lefthook will
-      // initialize hooks on the next `prepare` run after git is initialized.
-    }
+    // The result is deliberately ignored: lefthook install fails with exit
+    // code 128 when not in a git repository. The dependency and prepare script
+    // are still set up, so lefthook will initialize hooks on the next
+    // `prepare` run after git is initialized.
+    spawnSync(command, args, { stdio: "pipe" });
   },
   update: async (packageManager: PackageManagerName) => {
     const existingContents = await readFile(path, "utf-8");