fix: normalize CLI paths to POSIX so sourcemap sources[] is portable on Windows

examples/esbuild/vitest.config.ts

@@ -2,11 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'esbuild.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'esbuild.e2e.test.ts')],
+    include: [include],
     restoreMocks: true,
   },
 });

examples/parcel/vitest.config.ts

@@ -2,10 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'parcel.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'parcel.e2e.test.ts')],
+    include: [include],
+    restoreMocks: true,
   },
 });

examples/rolldown/vitest.config.ts

@@ -2,11 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'rolldown.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'rolldown.e2e.test.ts')],
+    include: [include],
     restoreMocks: true,
   },
 });

examples/rollup/vitest.config.ts

@@ -2,11 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'rollup.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'rollup.e2e.test.ts')],
+    include: [include],
     restoreMocks: true,
   },
 });

examples/rsbuild/vitest.config.ts

@@ -2,11 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'rsbuild.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'rsbuild.e2e.test.ts')],
+    include: [include],
     restoreMocks: true,
   },
 });

examples/rspack/vitest.config.ts

@@ -2,11 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'rspack.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'rspack.e2e.test.ts')],
+    include: [include],
     restoreMocks: true,
   },
 });

examples/vite/vitest.config.ts

@@ -2,11 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'vite.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'vite.e2e.test.ts')],
+    include: [include],
     restoreMocks: true,
   },
 });

examples/webpack/vitest.config.ts

@@ -2,11 +2,19 @@ import { resolve } from 'node:path';
 
 import { defineConfig } from 'vitest/config';
 
+// resolve() returns backslash paths on Windows; tinyglobby (used by vitest's
+// include matcher) only matches forward-slash patterns, so without normalizing
+// the test file is silently never discovered on Windows ("No test files found").
+const include = resolve(import.meta.dirname, 'webpack.e2e.test.ts').replaceAll(
+  '\\',
+  '/'
+);
+
 export default defineConfig({
   test: {
     environment: 'node',
     globals: true,
-    include: [resolve(import.meta.dirname, 'webpack.e2e.test.ts')],
+    include: [include],
     restoreMocks: true,
   },
 });

packages/core/__tests__/correctness.test.ts

@@ -1,10 +1,17 @@
 import { spawnSync } from 'node:child_process';
 import { mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join, resolve } from 'node:path';
+import { join, resolve, sep } from 'node:path';
 
 import fft from '../src/index.js';
 
+// `import.meta.dirname` is OS-native (backslash on Windows), so `resolve()`
+// also returns backslash on Windows. Snapshot fixture paths and CLI args
+// must be POSIX-style — sourcemap `sources[]` and tinyglobby's include
+// matchers expect forward-slash.
+const toPosix =
+  sep === '\\' ? (p: string) => p.replaceAll('\\', '/') : (p: string) => p;
+
 type Format = 'compact' | 'pretty' | 'preserve';
 interface SnapshotCase {
   fixture: string;
@@ -18,11 +25,11 @@ interface SnapshotCase {
 }
 
 function outputsDir(): string {
-  return resolve(import.meta.dirname, 'outputs');
+  return toPosix(resolve(import.meta.dirname, 'outputs'));
 }
 
 function inputsDir(): string {
-  return resolve(import.meta.dirname, 'inputs');
+  return toPosix(resolve(import.meta.dirname, 'inputs'));
 }
 
 const FULL_FIXTURE = 'source.flow';

packages/core/src/cli/__tests__/run.test.ts

@@ -2,6 +2,13 @@ import { describe, expect, it, vi } from 'vitest';
 
 import { runCli } from '../run.js';
 
+// Use a platform-absolute fake cwd so node:path.resolve produces the same
+// shape on Windows (where bare `/repo` is treated as drive-relative and
+// gets the current drive prepended) and POSIX. The CLI internally normalizes
+// to forward-slash, so all expected values use forward-slash regardless of
+// platform.
+const FAKE_CWD = process.platform === 'win32' ? 'C:/repo' : '/repo';
+
 type RawSourceMap = import('source-map').RawSourceMap;
 
 function createMap(file: string): RawSourceMap {
@@ -23,7 +30,7 @@ function createDeps() {
 
   return {
     deps: {
-      cwd: () => '/repo',
+      cwd: () => FAKE_CWD,
       readFile,
       stderr: {
         write(chunk: string) {
@@ -50,15 +57,15 @@ describe('CLI runner', () => {
   it('transforms a file without source maps by default', async () => {
     const { deps, readFile, transform, writeFile } = createDeps();
     readFile.mockImplementation(async (path) => {
-      if (path === '/repo/src/input.js') {
+      if (path === `${FAKE_CWD}/src/input.js`) {
         return 'const answer: number = 42;';
       }
 
       throw new Error(`Unexpected read: ${path}`);
     });
     transform.mockResolvedValue({
       code: 'const answer = 42;\n',
-      map: createMap('/repo/dist/output.js'),
+      map: createMap(`${FAKE_CWD}/dist/output.js`),
     });
 
     const exitCode = await runCli(
@@ -68,29 +75,29 @@ describe('CLI runner', () => {
 
     expect(exitCode).toBe(0);
     expect(transform).toHaveBeenCalledWith({
-      filename: '/repo/src/input.js',
+      filename: `${FAKE_CWD}/src/input.js`,
       source: 'const answer: number = 42;',
       sourcemap: false,
     });
     expect(writeFile).toHaveBeenCalledTimes(1);
     expect(writeFile).toHaveBeenCalledWith(
-      '/repo/dist/output.js',
+      `${FAKE_CWD}/dist/output.js`,
       'const answer = 42;\n'
     );
   });
 
   it('writes code plus sourcemap files when --source-map is enabled', async () => {
     const { deps, readFile, transform, writeFile } = createDeps();
     readFile.mockImplementation(async (path) => {
-      if (path === '/repo/src/input.js') {
+      if (path === `${FAKE_CWD}/src/input.js`) {
         return 'const answer: number = 42;';
       }
 
       throw new Error(`Unexpected read: ${path}`);
     });
     transform.mockResolvedValue({
       code: 'const answer = 42;\n',
-      map: createMap('/repo/dist/output.js'),
+      map: createMap(`${FAKE_CWD}/dist/output.js`),
     });
 
     const exitCode = await runCli(
@@ -110,20 +117,20 @@ describe('CLI runner', () => {
     expect(exitCode).toBe(0);
     expect(transform).toHaveBeenCalledWith({
       dialect: 'flow',
-      filename: '/repo/src/input.js',
+      filename: `${FAKE_CWD}/src/input.js`,
       format: 'pretty',
       source: 'const answer: number = 42;',
       sourcemap: true,
     });
     expect(writeFile).toHaveBeenNthCalledWith(
       1,
-      '/repo/dist/output.js',
+      `${FAKE_CWD}/dist/output.js`,
       'const answer = 42;\n//# sourceMappingURL=output.js.map\n'
     );
     expect(writeFile).toHaveBeenNthCalledWith(
       2,
-      '/repo/dist/output.js.map',
-      `${JSON.stringify(createMap('/repo/dist/output.js'), null, 2)}\n`
+      `${FAKE_CWD}/dist/output.js.map`,
+      `${JSON.stringify(createMap(`${FAKE_CWD}/dist/output.js`), null, 2)}\n`
     );
   });
 
@@ -138,7 +145,7 @@ describe('CLI runner', () => {
 
     expect(exitCode).toBe(0);
     expect(transform).toHaveBeenCalledWith({
-      filename: '/repo/src/input.js',
+      filename: `${FAKE_CWD}/src/input.js`,
       source: 'const answer: number = 42;',
       sourcemap: false,
     });
@@ -161,7 +168,7 @@ describe('CLI runner', () => {
     expect(exitCode).toBe(0);
     expect(transform).toHaveBeenCalledWith({
       comments: true,
-      filename: '/repo/src/input.js',
+      filename: `${FAKE_CWD}/src/input.js`,
       format: 'preserve',
       source: 'const answer: number = 42;',
       sourcemap: false,
@@ -182,7 +189,7 @@ describe('CLI runner', () => {
     expect(exitCode).toBe(0);
     expect(transform).toHaveBeenCalledWith({
       comments: true,
-      filename: '/repo/src/input.js',
+      filename: `${FAKE_CWD}/src/input.js`,
       source: '/* keep */\nconst answer: number = 42;',
       sourcemap: false,
     });
@@ -192,21 +199,21 @@ describe('CLI runner', () => {
 
   it('loads an input sourcemap file and forwards it to transform', async () => {
     const { deps, readFile, transform, writeFile } = createDeps();
-    const inputMap = createMap('/repo/src/input.js');
+    const inputMap = createMap(`${FAKE_CWD}/src/input.js`);
     readFile.mockImplementation(async (path) => {
-      if (path === '/repo/src/input.js') {
+      if (path === `${FAKE_CWD}/src/input.js`) {
         return 'const answer: number = 42;';
       }
 
-      if (path === '/repo/maps/input.js.map') {
+      if (path === `${FAKE_CWD}/maps/input.js.map`) {
         return JSON.stringify(inputMap);
       }
 
       throw new Error(`Unexpected read: ${path}`);
     });
     transform.mockResolvedValue({
       code: 'const answer = 42;\n',
-      map: createMap('/repo/dist/output.js'),
+      map: createMap(`${FAKE_CWD}/dist/output.js`),
     });
 
     const exitCode = await runCli(
@@ -223,7 +230,7 @@ describe('CLI runner', () => {
 
     expect(exitCode).toBe(0);
     expect(transform).toHaveBeenCalledWith({
-      filename: '/repo/src/input.js',
+      filename: `${FAKE_CWD}/src/input.js`,
       inputSourceMap: inputMap,
       source: 'const answer: number = 42;',
       sourcemap: true,