feat: enable decorator test

Author: sapphi-red

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

@@ -268,7 +268,7 @@ async function prepareRolldownScanner(
   const { plugins: pluginsFromConfig = [], ...rollupOptions } =
     environment.config.optimizeDeps.rollupOptions ?? {}
 
-  // TODO: enableDecorators when needed
+  // TODO: enableDecorators when needed, wait for rolldown option
   // The plugin pipeline automatically loads the closest tsconfig.json.
   // But esbuild doesn't support reading tsconfig.json if the plugin has resolved the path (https://github.com/evanw/esbuild/issues/2265).
   // Due to syntax incompatibilities between the experimental decorators in TypeScript and TC39 decorators,

packages/vite/src/node/plugins/oxc.ts

@@ -1,4 +1,5 @@
 import path from 'node:path'
+import url from 'node:url'
 import { createRequire } from 'node:module'
 import type {
   TransformOptions as OxcTransformOptions,
@@ -15,6 +16,7 @@ import {
   createFilter,
   ensureWatchedFile,
   generateCodeFrame,
+  normalizePath,
 } from '../utils'
 import type { ResolvedConfig } from '../config'
 import type { Plugin } from '../plugin'
@@ -87,7 +89,6 @@ export async function transformWithOxc(
         ensureWatchedFile(watcher, tsconfigFile, config.root)
       }
       const loadedCompilerOptions = loadedTsconfig.compilerOptions ?? {}
-      // TODO: experimentalDecorators
 
       // when both the normal options and tsconfig is set,
       // we want to prioritize the normal options
@@ -129,6 +130,14 @@ export async function transformWithOxc(
           resolvedOptions.jsx = jsxOptions
         }
       }
+      if (resolvedOptions.decorator?.legacy === undefined) {
+        const experimentalDecorators =
+          loadedCompilerOptions.experimentalDecorators
+        if (experimentalDecorators !== undefined) {
+          resolvedOptions.decorator ??= {}
+          resolvedOptions.decorator.legacy = experimentalDecorators
+        }
+      }
 
       /**
        * | preserveValueImports | importsNotUsedAsValues | verbatimModuleSyntax | onlyRemoveTypeImports |
@@ -335,6 +344,7 @@ export function oxcPlugin(config: ResolvedConfig): Plugin {
 
     return result
   }
+  const _filename = normalizePath(url.fileURLToPath(import.meta.url))
 
   let server: ViteDevServer
 
@@ -343,6 +353,38 @@ export function oxcPlugin(config: ResolvedConfig): Plugin {
     configureServer(_server) {
       server = _server
     },
+    resolveId: {
+      // @ts-expect-error TODO: fix the types
+      filter: {
+        id: /^@babel\/runtime\//,
+      },
+      async handler(id, _importer, opts) {
+        if (!id.startsWith('@babel/runtime/')) return
+
+        if (id === '@babel/runtime/helpers/decorateParam') {
+          return id
+        }
+
+        // @babel/runtime imports will be injected by OXC transform
+        // since it's injected by the transform, @babel/runtime should be resolved to the one Vite depends on
+        const resolved = await this.resolve(id, _filename, opts)
+        return resolved
+      },
+    },
+    // TODO: applied a workaround for now
+    load: {
+      handler(id) {
+        if (id === '@babel/runtime/helpers/decorateParam') {
+          return `function __decorateParam(paramIndex, decorator) {
+  return function (target, key) {
+    decorator(target, key, paramIndex);
+  };
+}
+
+export { __decorateParam as default };`
+        }
+      },
+    },
     async transform(code, id) {
       if (filter(id) || filter(cleanUrl(id))) {
         const modifiedOxcTransformOptions = getModifiedOxcTransformOptions(
@@ -505,21 +547,23 @@ export function resolveOxcTranspileOptions(
   }
 }
 
-let rolldownDir: string
-
-async function generateRuntimeHelpers(
-  runtimeHelpers: readonly [string, string][],
-): Promise<string> {
-  if (!rolldownDir) {
-    let dir = createRequire(import.meta.url).resolve('rolldown')
-    while (dir && path.basename(dir) !== 'rolldown') {
+let viteDir: string
+function getViteDir() {
+  if (!viteDir) {
+    let dir = createRequire(import.meta.url).resolve('vite')
+    while (dir && path.basename(dir) !== 'vite') {
       dir = path.dirname(dir)
     }
-    rolldownDir = dir
+    viteDir = dir
   }
+  return viteDir
+}
 
+async function generateRuntimeHelpers(
+  runtimeHelpers: readonly [string, string][],
+): Promise<string> {
   const bundle = await rolldown({
-    cwd: rolldownDir,
+    cwd: getViteDir(),
     input: 'entrypoint',
     platform: 'neutral',
     logLevel: 'silent',

vitest.config.e2e.ts

@@ -19,7 +19,6 @@ export default defineConfig({
         ? [
             './playground/object-hooks/**/*.spec.[tj]s', // object hook sequential
             './playground/optimize-deps/**/*.spec.[tj]s', // https://github.com/rolldown/rolldown/issues/2031
-            './playground/tsconfig-json/__tests__/**/*.spec.[tj]s', // decorators is not supported by oxc
           ]
         : []),
       ...defaultExclude,