chore: fix source map support when developing Vite (#20167)

Author: sapphi-red

packages/vite/bin/vite.js

@@ -3,10 +3,8 @@ import { performance } from 'node:perf_hooks'
 import module from 'node:module'
 
 if (!import.meta.url.includes('node_modules')) {
-  try {
-    // only available as dev dependency
-    await import('source-map-support').then((r) => r.default.install())
-  } catch {}
+  // eslint-disable-next-line n/no-unsupported-features/node-builtins -- only used in dev
+  process.setSourceMapsEnabled(true)
 
   process.on('unhandledRejection', (err) => {
     throw new Error('UNHANDLED PROMISE REJECTION', { cause: err })

packages/vite/package.json

@@ -144,7 +144,6 @@
     "sass": "^1.89.0",
     "sass-embedded": "^1.89.0",
     "sirv": "^3.0.1",
-    "source-map-support": "^0.5.21",
     "strip-literal": "^3.0.0",
     "terser": "^5.39.2",
     "tsconfck": "^3.1.6",

packages/vite/rolldown.config.ts

@@ -10,7 +10,6 @@ import licensePlugin from './rollupLicensePlugin'
 const pkg = JSON.parse(
   readFileSync(new URL('./package.json', import.meta.url)).toString(),
 )
-
 const __dirname = fileURLToPath(new URL('.', import.meta.url))
 
 const envConfig = defineConfig({
@@ -147,6 +146,7 @@ const nodeConfig = defineConfig({
       'Vite',
     ) as Plugin,
     writeTypesPlugin(),
+    enableSourceMapsInWatchModePlugin(),
     externalizeDepsInWatchPlugin(),
   ],
 })
@@ -162,7 +162,7 @@ const moduleRunnerConfig = defineConfig({
     'rollup/parseAst',
     ...Object.keys(pkg.dependencies),
   ],
-  plugins: [bundleSizeLimit(54)],
+  plugins: [bundleSizeLimit(54), enableSourceMapsInWatchModePlugin()],
   output: {
     ...sharedNodeOptions.output,
     minify: {
@@ -182,6 +182,17 @@ export default defineConfig([
 
 // #region Plugins
 
+function enableSourceMapsInWatchModePlugin(): Plugin {
+  return {
+    name: 'enable-source-maps',
+    outputOptions(options) {
+      if (this.meta.watchMode) {
+        options.sourcemap = 'inline'
+      }
+    },
+  }
+}
+
 function writeTypesPlugin(): Plugin {
   return {
     name: 'write-types',