fix(browser): skip esbuild.legalComments when using rolldown-vite (#9803)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: hi-ogawa <4232207+hi-ogawa@users.noreply.github.com>
Co-authored-by: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>

Author: Copilot

packages/browser/src/node/plugin.ts

@@ -355,7 +355,9 @@ export default (parentServer: ParentBrowserProject, base = '/'): Plugin[] => {
       enforce: 'post',
       async config(viteConfig) {
         // Enables using ignore hint for coverage providers with @preserve keyword
-        if (viteConfig.esbuild !== false) {
+        // Only set esbuild options when not using rolldown-vite (Vite 8+),
+        // which uses oxc for transformation instead of esbuild
+        if (!rolldownVersion && viteConfig.esbuild !== false) {
           viteConfig.esbuild ||= {}
           viteConfig.esbuild.legalComments = 'inline'
         }

test/cli/test/oxc.test.ts

@@ -0,0 +1,44 @@
+import { runInlineTests } from '#test-utils'
+import { expect, test } from 'vitest'
+
+test('oxc config on browser', async () => {
+  const result = await runInlineTests({
+    // needs a config file to reproduce
+    // https://github.com/vitest-dev/vitest/issues/9800
+    'vitest.config.ts': `
+import { playwright } from '@vitest/browser-playwright'
+import { defineConfig } from 'vite'
+
+export default defineConfig({
+  test: {
+    browser: {
+      enabled: true,
+      headless: true,
+      provider: playwright(),
+      instances: [
+        { browser: 'chromium' },
+      ],
+    },
+  },
+  oxc: {
+    jsx: {
+      refresh: false,
+    }
+  }
+})
+`,
+    'basic.test.ts': `
+import { test } from "vitest";
+test('basic', () => {});
+`,
+  })
+
+  expect(result.stderr).toMatchInlineSnapshot(`""`)
+  expect(result.errorTree()).toMatchInlineSnapshot(`
+    {
+      "basic.test.ts": {
+        "basic": "passed",
+      },
+    }
+  `)
+})