fix: sourcemaps for pirates hook.

packages/core/register.mjs

@@ -1,18 +1,38 @@
-import { register } from 'node:module'
+import * as NodeModule from 'node:module'
 
 import { addHook } from 'pirates'
 
 import { OxcTransformer } from './index.js'
 
+// Destructure from NodeModule namespace to support older Node.js versions
+const { register, setSourceMapsSupport } = NodeModule
+
 const DEFAULT_EXTENSIONS = new Set(['.js', '.jsx', '.ts', '.tsx', '.mjs', '.mts', '.cjs', '.cts', '.es6', '.es'])
 
 register('@oxc-node/core/esm', import.meta.url)
 
+if (typeof setSourceMapsSupport === 'function') {
+  setSourceMapsSupport(true, { nodeModules: true, generatedCode: true })
+} else if (typeof process.setSourceMapsEnabled === 'function') {
+  process.setSourceMapsEnabled(true)
+}
+
 const transformer = new OxcTransformer(process.cwd())
+const SOURCEMAP_PREFIX = '\n//# sourceMappingURL='
+const SOURCEMAP_MIME = 'data:application/json;charset=utf-8;base64,'
 
 addHook(
   (code, filename) => {
-    return transformer.transform(filename, code).source()
+    const output = transformer.transform(filename, code)
+    let transformed = output.source()
+    const sourceMap = output.sourceMap()
+
+    if (sourceMap) {
+      const inlineMap = Buffer.from(sourceMap, 'utf8').toString('base64')
+      transformed += SOURCEMAP_PREFIX + SOURCEMAP_MIME + inlineMap
+    }
+
+    return transformed
   },
   {
     ext: Array.from(DEFAULT_EXTENSIONS),

packages/integrate-ava/__tests__/cli.spec.ts

@@ -0,0 +1,63 @@
+import test, { ExecutionContext } from 'ava'
+import { spawnSync } from 'node:child_process'
+import { fileURLToPath, pathToFileURL } from 'node:url'
+
+const STACKTRACE_LINE = 6
+const STACKTRACE_COLUMN = 12
+const FIXTURE_PATHS = new Map(
+  ['stacktrace-esm.ts', 'stacktrace-esm.mts', 'stacktrace-cjs.cts'].map((name) => [
+    name,
+    fileURLToPath(new URL(`./fixtures/${name}`, import.meta.url)),
+  ]),
+)
+const getFixturePath = (fixtureName: string) => {
+  const resolved = FIXTURE_PATHS.get(fixtureName)
+  if (!resolved) {
+    throw new Error(`Unknown fixture: ${fixtureName}`)
+  }
+  return resolved
+}
+const runCliFixture = (fixtureName: string) => {
+  const fixturePath = getFixturePath(fixtureName)
+  const result = spawnSync(
+    process.execPath,
+    ['--import', '@oxc-node/core/register', '--test', fixturePath],
+    {
+      encoding: 'utf8',
+      env: {
+        ...process.env,
+        NODE_OPTIONS: undefined,
+      },
+    },
+  )
+
+  return { ...result, fixturePath }
+}
+const escapeRegExp = (value: string) => value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
+const expectStackLocation = (t: ExecutionContext, output: string, fixturePath: string) => {
+  const fileUrl = pathToFileURL(fixturePath).href
+  const pattern = new RegExp(
+    `(?:${escapeRegExp(fileUrl)}|${escapeRegExp(fixturePath)}):(\\d+):(\\d+)`,
+    'g',
+  )
+  const matches = [...output.matchAll(pattern)]
+
+  t.true(matches.length > 0, 'stack trace should reference the failing fixture path')
+
+  const exactLocation = matches.find(([, line, column]) => {
+    return Number(line) === STACKTRACE_LINE && Number(column) === STACKTRACE_COLUMN
+  })
+
+  t.truthy(exactLocation, 'stack trace should include the original TypeScript location')
+}
+
+for (const fixture of FIXTURE_PATHS.keys()) {
+  test(`CLI stack trace for ${fixture}`, (t) => {
+    const { stdout, stderr, status, error, fixturePath } = runCliFixture(fixture)
+
+    t.falsy(error, error?.message)
+    t.not(status, 0, 'fixture should fail to trigger stack trace output')
+
+    expectStackLocation(t, `${stdout}${stderr}`, fixturePath)
+  })
+}

packages/integrate-ava/__tests__/fixtures/source-map-fixture.ts

@@ -0,0 +1,7 @@
+export function example(value: number): number {
+  if (value < 0) {
+    throw new Error('negative value')
+  }
+
+  return value * 2
+}

packages/integrate-ava/__tests__/fixtures/stacktrace-cjs.cts

@@ -0,0 +1,8 @@
+const { describe, it } = require('node:test')
+const assert = require('node:assert/strict')
+
+describe('stacktrace cts', () => {
+  it('should preserve stack trace', () => {
+    assert.ok(false)
+  })
+})

packages/integrate-ava/__tests__/fixtures/stacktrace-esm.mts

@@ -0,0 +1,8 @@
+import assert from 'node:assert/strict'
+import { describe, it } from 'node:test'
+
+describe('stacktrace esm mts', () => {
+  it('should preserve stack trace', () => {
+    assert.ok(false)
+  })
+})

packages/integrate-ava/__tests__/fixtures/stacktrace-esm.ts

@@ -0,0 +1,8 @@
+import assert from 'node:assert/strict'
+import { describe, it } from 'node:test'
+
+describe('stacktrace esm ts', () => {
+  it('should preserve stack trace', () => {
+    assert.ok(false)
+  })
+})