Fix formatter command execution on Windows

.changeset/friendly-tools-run.md

@@ -0,0 +1,5 @@
+---
+"@changesets/format": patch
+---
+
+Fix formatter command execution on Windows.

.gitattributes

@@ -0,0 +1 @@
+* text=auto eol=lf

.github/workflows/ci.yml

@@ -38,8 +38,8 @@ jobs:
           annotations: true
           advanced-security: false
 
-  test:
-    name: Test
+  checks:
+    name: Build, lint, and typecheck
     runs-on: ubuntu-latest
     timeout-minutes: 10
     env:
@@ -53,12 +53,6 @@ jobs:
 
       - uses: ./.github/actions/ci-setup
 
-      # Deno is needed for tests only
-      - name: Set up Deno
-        uses: denoland/setup-deno@667a34cdef165d8d2b2e98dde39547c9daac7282 # v2.0.4
-        with:
-          deno-version: 2.x
-
       - name: Build
         run: pnpm build
 
@@ -68,14 +62,35 @@ jobs:
       - name: Typecheck
         run: pnpm typecheck
 
+  test:
+    name: "Test on ${{ matrix.os }}"
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 10
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+      fail-fast: false
+    steps:
+      - name: Check out repo
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        with:
+          persist-credentials: false
+
+      - uses: ./.github/actions/ci-setup
+
+      - name: Set up Deno
+        uses: denoland/setup-deno@667a34cdef165d8d2b2e98dde39547c9daac7282 # v2.0.4
+        with:
+          deno-version: 2.x
+
       - name: Test
         run: pnpm test
 
   ci-ok:
     name: CI OK
     runs-on: ubuntu-latest
     if: always()
-    needs: [lint-workflows, test]
+    needs: [lint-workflows, checks, test]
     steps:
       - name: Exit with error if some jobs are not successful
         run: exit 1

package.json

@@ -26,7 +26,8 @@
     "release": "changeset publish"
   },
   "dependencies": {
-    "package-manager-detector": "^1.6.0"
+    "package-manager-detector": "^1.6.0",
+    "tinyexec": "^1.2.4"
   },
   "devDependencies": {
     "@changesets/changelog-github": "^1.0.0-next.3",

src/utils.ts

@@ -1,6 +1,6 @@
-import cp from "node:child_process";
 import path from "node:path";
 import { resolveCommand, type Agent } from "package-manager-detector";
+import { exec } from "tinyexec";
 
 /**
  * Traverse upwards from `startDir` to `stopDir` (inclusive), calling `cb` in each directory. If
@@ -37,24 +37,8 @@ export async function packageManagerExecute(
 }
 
 export async function spawnProcess(command: string, args: string[], cwd: string): Promise<void> {
-  return new Promise((resolve, reject) => {
-    const child = cp.spawn(command, args, { cwd });
-
-    let stderr = "";
-    child.stderr.on("data", (data) => {
-      stderr += data.toString();
-    });
-
-    child.on("exit", (code) => {
-      if (code === 0) {
-        resolve();
-      } else {
-        reject(new Error(`${command} exited with code ${code}. Stderr:\n${stderr}`));
-      }
-    });
-
-    child.on("error", (err) => {
-      reject(err);
-    });
+  await exec(command, args, {
+    nodeOptions: { cwd },
+    throwOnError: true,
   });
 }

tests/format.test.ts

@@ -3,28 +3,10 @@ import { expect, test, vi } from "vitest";
 import { format, type FormatterName } from "../src/index.ts";
 
 const mocks = vi.hoisted(() => ({
-  spawn: vi.fn().mockReturnValue({
-    // mock the bare-minimum based on how `src/utils.ts` uses `spawn`
-    on: (eventName: string, listener: Function) => {
-      if (eventName === "exit") {
-        listener(0); // simulate successful exit
-      }
-    },
-    stderr: { on: () => {} },
-  }),
+  exec: vi.fn().mockResolvedValue({ exitCode: 0, stderr: "", stdout: "" }),
 }));
 
-vi.mock(import("node:child_process"), async (importOriginal) => {
-  const mod = await importOriginal();
-  return {
-    ...mod,
-    spawn: mocks.spawn,
-    default: {
-      ...mod.default,
-      spawn: mocks.spawn,
-    },
-  };
-});
+vi.mock(import("tinyexec"), () => ({ exec: mocks.exec }));
 
 const cases: { formatter: FormatterName; expectedCommand: string[] }[] = [
   { formatter: "prettier", expectedCommand: ["npx", "prettier", "--write", "file.ts"] },
@@ -42,5 +24,8 @@ test.for(cases)("executes the correct command for $formatter", async (c) => {
   const result = await format(["file.ts"], { cwd: fixture.path, formatter: c.formatter });
   expect(result).toBe(true);
   const [command, ...args] = c.expectedCommand;
-  expect(mocks.spawn).toHaveBeenCalledWith(command, args, { cwd: fixture.path });
+  expect(mocks.exec).toHaveBeenCalledWith(command, args, {
+    nodeOptions: { cwd: fixture.path },
+    throwOnError: true,
+  });
 });