fix(optimizer): avoid mutating optimizeDeps.rollupOptions.transforms for stable optimizer hash (#417)

Author: hi-ogawa

packages/vite/src/node/optimizer/scan.ts

@@ -17,6 +17,7 @@ import {
   asyncFlatten,
   createDebugger,
   dataUrlRE,
+  deepClone,
   externalRE,
   isInNodeModules,
   isObject,
@@ -263,19 +264,20 @@ async function prepareRolldownScanner(
   const { tsconfig } = await loadTsconfigJsonForFile(
     path.join(environment.config.root, '_dummy.js'),
   )
-  rollupOptions.transform ??= {}
+  const transformOptions = deepClone(rollupOptions.transform) ?? {}
   setOxcTransformOptionsFromTsconfigOptions(
-    rollupOptions.transform,
+    transformOptions,
     tsconfig.compilerOptions,
     [], // NOTE: ignore warnings as the same warning will be shown by the plugin container
   )
-  if (typeof rollupOptions.transform.jsx === 'object') {
-    rollupOptions.transform.jsx.development ??= !environment.config.isProduction
+  if (typeof transformOptions.jsx === 'object') {
+    transformOptions.jsx.development ??= !environment.config.isProduction
   }
 
   async function build() {
     await scan({
       ...rollupOptions,
+      transform: transformOptions,
       input: entries,
       logLevel: 'silent',
       plugins,

packages/vite/src/node/utils.ts

@@ -1166,7 +1166,7 @@ type DeepWritable<T> =
         ? T
         : { -readonly [P in keyof T]: DeepWritable<T[P]> }
 
-function deepClone<T>(value: T): DeepWritable<T> {
+export function deepClone<T>(value: T): DeepWritable<T> {
   if (Array.isArray(value)) {
     return value.map((v) => deepClone(v)) as DeepWritable<T>
   }

playground/environment-react-ssr/vite.config.ts

@@ -37,6 +37,12 @@ export default defineConfig((env) => ({
         sourcemap: true,
         outDir: 'dist/client',
       },
+      optimizeDeps: {
+        rolldownOptions: {
+          // manual test for https://github.com/vitejs/rolldown-vite/issues/416
+          transform: {},
+        },
+      },
     },
     ssr: {
       optimizeDeps: {