feat: Pass through vite configLoader option to createViteServer

docs/.vitepress/scripts/cli-generator.ts

@@ -30,6 +30,7 @@ const skipConfig = new Set([
   'coverage.thresholds.lines',
   'standalone',
   'clearScreen',
+  'configLoader',
   'color',
   'run',
   'hideSkippedTests',

docs/advanced/api/index.md

@@ -61,7 +61,7 @@ The ["Running Tests"](/advanced/guide/tests#startvitest) guide has a usage examp
 ```ts
 function createVitest(
   mode: VitestRunMode,
-  options: UserConfig,
+  options: CliOptions,
   viteOverrides: ViteUserConfig = {},
   vitestOptions: VitestOptions = {},
 ): Promise<Vitest>

docs/guide/cli-generated.md

@@ -919,6 +919,12 @@ Removes colors from the console output
 
 Clear terminal screen when re-running tests during watch mode (default: `true`)
 
+### configLoader
+
+- **CLI:** `--configLoader <loader>`
+
+Use `bundle` to bundle the config with esbuild or `runner` (experimental) to process it on the fly. This is only available in vite version 6.1.0 and above. (default: `bundle`)
+
 ### standalone
 
 - **CLI:** `--standalone`

packages/browser/src/node/index.ts

@@ -58,6 +58,7 @@ export async function createBrowserServer(
     },
     mode: project.config.mode,
     configFile: configPath,
+    configLoader: project.vite.config.inlineConfig.configLoader,
     // watch is handled by Vitest
     server: {
       hmr: false,

packages/vitest/src/node/cli/cli-api.ts

@@ -1,4 +1,4 @@
-import type { UserConfig as ViteUserConfig } from 'vite'
+import type { InlineConfig as ViteInlineConfig, UserConfig as ViteUserConfig } from 'vite'
 import type { environments } from '../../integrations/env'
 import type { Vitest, VitestOptions } from '../core'
 import type { TestModule, TestSuite } from '../reporters/reported-tasks'
@@ -28,6 +28,14 @@ export interface CliOptions extends UserConfig {
    * Output collected test files only
    */
   filesOnly?: boolean
+
+  /**
+   * Override vite config's configLoader from cli.
+   * Use `bundle` to bundle the config with esbuild or `runner` (experimental) to process it on the fly (default: `bundle`).
+   * This is only available with **vite version 6.1.0** and above.
+   * @experimental
+   */
+  configLoader?: ViteInlineConfig extends { configLoader?: infer T } ? T : never
 }
 
 /**

packages/vitest/src/node/cli/cli-config.ts

@@ -806,6 +806,11 @@ export const cliOptionsConfig: VitestCLIOptions = {
     description:
       'Clear terminal screen when re-running tests during watch mode (default: `true`)',
   },
+  configLoader: {
+    description:
+      'Use `bundle` to bundle the config with esbuild or `runner` (experimental) to process it on the fly. This is only available in vite version 6.1.0 and above. (default: `bundle`)',
+    argument: '<loader>',
+  },
   standalone: {
     description:
       'Start Vitest without running tests. File filters will be ignored, tests will be running only on change (default: `false`)',

packages/vitest/src/node/create.ts

@@ -2,8 +2,9 @@ import type {
   InlineConfig as ViteInlineConfig,
   UserConfig as ViteUserConfig,
 } from 'vite'
+import type { CliOptions } from './cli/cli-api'
 import type { VitestOptions } from './core'
-import type { UserConfig, VitestRunMode } from './types/config'
+import type { VitestRunMode } from './types/config'
 import { resolve } from 'node:path'
 import { slash } from '@vitest/utils'
 import { findUp } from 'find-up'
@@ -15,7 +16,7 @@ import { createViteServer } from './vite'
 
 export async function createVitest(
   mode: VitestRunMode,
-  options: UserConfig,
+  options: CliOptions,
   viteOverrides: ViteUserConfig = {},
   vitestOptions: VitestOptions = {},
 ): Promise<Vitest> {
@@ -33,6 +34,7 @@ export async function createVitest(
 
   const config: ViteInlineConfig = {
     configFile: configPath,
+    configLoader: options.configLoader,
     // this will make "mode": "test" | "benchmark" inside defineConfig
     mode: options.mode || mode,
     plugins: await VitestPlugin(options, ctx),

packages/vitest/src/node/project.ts

@@ -742,6 +742,7 @@ export async function initializeProject(
   const config: ViteInlineConfig = {
     ...restOptions,
     configFile,
+    configLoader: ctx.vite.config.inlineConfig.configLoader,
     // this will make "mode": "test" | "benchmark" inside defineConfig
     mode: options.test?.mode || options.mode || ctx.config.mode,
     plugins: [

test/cli/deps/linked/index.ts

@@ -0,0 +1 @@
+export default 'ok' satisfies string

test/cli/deps/linked/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@vitest/test-dep-linked",
+  "type": "module",
+  "private": true,
+  "exports": {
+    "./ts": "./index.ts"
+  }
+}

test/cli/fixtures/config-loader/browser/basic.test.ts

@@ -0,0 +1,3 @@
+import { test } from "vitest"
+
+test("browser ok", () => {})

test/cli/fixtures/config-loader/browser/vitest.config.ts

@@ -0,0 +1,17 @@
+import { defineConfig } from "vitest/config"
+import "@vitest/test-dep-linked/ts";
+
+export default defineConfig({
+  test: {
+    browser: {
+      enabled: true,
+      provider: 'playwright',
+      headless: true,
+      instances: [
+        {
+          browser: 'chromium',
+        }
+      ]
+    }
+  }
+})

test/cli/fixtures/config-loader/node/basic.test.ts

@@ -0,0 +1,3 @@
+import { test } from "vitest"
+
+test("node ok", () => {})

test/cli/fixtures/config-loader/node/vitest.config.ts

@@ -0,0 +1,4 @@
+import { defineConfig } from "vitest/config"
+import "@vitest/test-dep-linked/ts";
+
+export default defineConfig({})

test/cli/fixtures/config-loader/vitest.config.ts

@@ -0,0 +1,11 @@
+import { defineConfig } from "vitest/config"
+import "@vitest/test-dep-linked/ts";
+
+export default defineConfig({
+  test: {
+    workspace: [
+      "browser/vitest.config.ts",
+      "node/vitest.config.ts",
+    ],
+  },
+})

test/cli/package.json

@@ -11,6 +11,7 @@
     "@vitejs/plugin-basic-ssl": "^1.2.0",
     "@vitest/runner": "workspace:^",
     "@vitest/test-dep-error": "file:./deps/error",
+    "@vitest/test-dep-linked": "link:./deps/linked",
     "@vitest/utils": "workspace:*",
     "debug": "^4.4.0",
     "unplugin-swc": "^1.5.1",

test/cli/test/config-loader.test.ts

@@ -0,0 +1,26 @@
+import { expect, test } from 'vitest'
+import { runVitestCli } from '../../test-utils'
+
+test('configLoader default', async () => {
+  const { vitest, exitCode } = await runVitestCli(
+    'run',
+    '--root',
+    'fixtures/config-loader',
+  )
+  expect(vitest.stderr).toContain('failed to load config')
+  expect(exitCode).not.toBe(0)
+})
+
+test('configLoader runner', async () => {
+  const { vitest, exitCode } = await runVitestCli(
+    'run',
+    '--root',
+    'fixtures/config-loader',
+    '--configLoader',
+    'runner',
+  )
+  expect(vitest.stderr).toBe('')
+  expect(vitest.stdout).toContain('✓  node')
+  expect(vitest.stdout).toContain('✓  browser (chromium)')
+  expect(exitCode).toBe(0)
+})