fix(ssr): load sourcemaps alongside modules

packages/vite/src/node/ssr/ssrModuleLoader.ts

@@ -10,6 +10,7 @@ import {
 import { transformRequest } from '../server/transformRequest'
 import type { InternalResolveOptionsWithOverrideConditions } from '../plugins/resolve'
 import { tryNodeResolve } from '../plugins/resolve'
+import { genSourceMapUrl } from '../server/sourcemap'
 import {
   ssrDynamicImportKey,
   ssrExportAllKey,
@@ -25,6 +26,16 @@ interface SSRContext {
 
 type SSRModule = Record<string, any>
 
+// eslint-disable-next-line @typescript-eslint/no-empty-function
+const AsyncFunction = async function () {}.constructor as typeof Function
+let fnDeclarationLineCount = 0
+{
+  const body = '/*code*/'
+  const source = new AsyncFunction('a', 'b', body).toString()
+  fnDeclarationLineCount =
+    source.slice(0, source.indexOf(body)).split('\n').length - 1
+}
+
 const pendingModules = new Map<string, Promise<SSRModule>>()
 const pendingImports = new Map<string, string[]>()
 
@@ -181,17 +192,28 @@ async function instantiateModule(
     }
   }
 
+  let sourceMapSuffix = ''
+  if (result.map) {
+    const moduleSourceMap = Object.assign({}, result.map, {
+      // currently we need to offset the line
+      // https://github.com/nodejs/node/issues/43047#issuecomment-1180632750
+      mappings: ';'.repeat(fnDeclarationLineCount) + result.map.mappings,
+    })
+    sourceMapSuffix =
+      '\n//# sourceMappingURL=' + genSourceMapUrl(moduleSourceMap)
+  }
+
   try {
-    // eslint-disable-next-line @typescript-eslint/no-empty-function
-    const AsyncFunction = async function () {}.constructor as typeof Function
     const initModule = new AsyncFunction(
       `global`,
       ssrModuleExportsKey,
       ssrImportMetaKey,
       ssrImportKey,
       ssrDynamicImportKey,
       ssrExportAllKey,
-      '"use strict";' + result.code + `\n//# sourceURL=${mod.url}`,
+      '"use strict";' +
+        result.code +
+        `\n//# sourceURL=${mod.url}${sourceMapSuffix}`,
     )
     await initModule(
       context.global,

playground/ssr-html/__tests__/ssr-html.spec.ts

@@ -1,3 +1,6 @@
+import { execFile } from 'node:child_process'
+import { promisify } from 'node:util'
+import path from 'node:path'
 import fetch from 'node-fetch'
 import { describe, expect, test } from 'vitest'
 import { port } from './serve'
@@ -55,3 +58,27 @@ describe.runIf(isServe)('hmr', () => {
     }, '[wow]')
   })
 })
+
+describe.runIf(isServe)('stacktrace', () => {
+  const execFileAsync = promisify(execFile)
+
+  for (const sourcemapsEnabled of [false, true]) {
+    test(`stacktrace is correct when sourcemaps is${
+      sourcemapsEnabled ? '' : ' not'
+    } enabled in Node.js`, async () => {
+      const testStacktraceFile = path.resolve(
+        __dirname,
+        '../test-stacktrace.js',
+      )
+
+      const p = await execFileAsync('node', [
+        testStacktraceFile,
+        '' + sourcemapsEnabled,
+      ])
+      const line = p.stdout
+        .split('\n')
+        .find((line) => line.includes('Module.error'))
+      expect(line.trim()).toMatch(/[\\/]src[\\/]error\.js:2:9/)
+    })
+  }
+})

playground/ssr-html/package.json

@@ -6,7 +6,9 @@
   "scripts": {
     "dev": "node server",
     "serve": "NODE_ENV=production node server",
-    "debug": "node --inspect-brk server"
+    "debug": "node --inspect-brk server",
+    "test-stacktrace:off": "node test-stacktrace false",
+    "test-stacktrace:on": "node test-stacktrace true"
   },
   "dependencies": {},
   "devDependencies": {

playground/ssr-html/src/error.js

@@ -0,0 +1,3 @@
+export function error() {
+  throw new Error('e')
+}

playground/ssr-html/test-stacktrace.js

@@ -0,0 +1,47 @@
+import path from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { createServer } from 'vite'
+
+const isSourceMapEnabled = process.argv[2] === 'true'
+process.setSourceMapsEnabled(isSourceMapEnabled)
+console.log('# sourcemaps enabled:', isSourceMapEnabled)
+
+const version = (() => {
+  const m = process.version.match(/^v(\d+)\.(\d+)\.\d+$/)
+  if (!m) throw new Error(`Failed to parse version: ${process.version}`)
+
+  return { major: +m[1], minor: +m[2] }
+})()
+
+// https://github.com/nodejs/node/pull/43428
+const isFunctionSourceMapSupported =
+  (version.major === 16 && version.minor >= 17) ||
+  (version.major === 18 && version.minor >= 6) ||
+  version.major >= 19
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url))
+const isTest = process.env.VITEST
+
+const vite = await createServer({
+  root: __dirname,
+  logLevel: isTest ? 'error' : 'info',
+  server: {
+    middlewareMode: true,
+  },
+  appType: 'custom',
+})
+
+const mod = await vite.ssrLoadModule('/src/error.js')
+try {
+  mod.error()
+} catch (e) {
+  // this should not be called
+  // when sourcemap support for `new Function` is supported and sourcemap is enabled
+  // because the stacktrace is already rewritten by Node.js
+  if (!(isSourceMapEnabled && isFunctionSourceMapSupported)) {
+    vite.ssrFixStacktrace(e)
+  }
+  console.log(e)
+}
+
+await vite.close()