perf: use experimental meta.resolve flag instead of a custom loader (#8567)

Author: sheremet-va

package.json

@@ -64,7 +64,7 @@
     "typescript": "^5.9.2",
     "unplugin-isolated-decl": "^0.15.1",
     "unplugin-oxc": "^0.5.1",
-    "vite": "^6.3.5",
+    "vite": "^7.1.5",
     "vitest": "workspace:*",
     "zx": "^8.8.1"
   },

packages/vitest/src/node/pool.ts

@@ -4,14 +4,18 @@ import type { TestProject } from './project'
 import type { TestSpecification } from './spec'
 import type { BuiltinPool, Pool } from './types/pool-options'
 import { isatty } from 'node:tty'
+import { resolve } from 'pathe'
 import { version as viteVersion } from 'vite'
+import { rootDir } from '../paths'
 import { isWindows } from '../utils/env'
 import { createForksPool } from './pools/forks'
 import { createThreadsPool } from './pools/threads'
 import { createTypecheckPool } from './pools/typecheck'
 import { createVmForksPool } from './pools/vmForks'
 import { createVmThreadsPool } from './pools/vmThreads'
 
+const suppressWarningsPath = resolve(rootDir, './suppress-warnings.cjs')
+
 export type RunWithFiles = (
   files: TestSpecification[],
   invalidates?: string[]
@@ -100,7 +104,13 @@ export function createPool(ctx: Vitest): ProcessPool {
 
   async function executeTests(method: 'runTests' | 'collectTests', files: TestSpecification[], invalidate?: string[]) {
     const options: PoolProcessOptions = {
-      execArgv: [...execArgv, ...conditions],
+      execArgv: [
+        ...execArgv,
+        ...conditions,
+        '--experimental-import-meta-resolve',
+        '--require',
+        suppressWarningsPath,
+      ],
       env: {
         TEST: 'true',
         VITEST: 'true',

packages/vitest/src/node/pools/vmForks.ts

@@ -13,14 +13,11 @@ import { resolve } from 'node:path'
 import v8 from 'node:v8'
 import { createBirpc } from 'birpc'
 import Tinypool from 'tinypool'
-import { rootDir } from '../../paths'
 import { wrapSerializableConfig } from '../../utils/config-helpers'
 import { getWorkerMemoryLimit, stringToBytes } from '../../utils/memory-limit'
 import { groupFilesByEnv } from '../../utils/test-helpers'
 import { createMethodsRPC } from './rpc'
 
-const suppressWarningsPath = resolve(rootDir, './suppress-warnings.cjs')
-
 function createChildProcessChannel(project: TestProject, collect: boolean) {
   const emitter = new EventEmitter()
 
@@ -106,10 +103,7 @@ export function createVmForksPool(
 
     env,
     execArgv: [
-      '--experimental-import-meta-resolve',
       '--experimental-vm-modules',
-      '--require',
-      suppressWarningsPath,
       ...(poolOptions.execArgv ?? []),
       ...execArgv,
     ],

packages/vitest/src/node/pools/vmThreads.ts

@@ -13,13 +13,10 @@ import { resolve } from 'node:path'
 import { MessageChannel } from 'node:worker_threads'
 import { createBirpc } from 'birpc'
 import Tinypool from 'tinypool'
-import { rootDir } from '../../paths'
 import { getWorkerMemoryLimit, stringToBytes } from '../../utils/memory-limit'
 import { groupFilesByEnv } from '../../utils/test-helpers'
 import { createMethodsRPC } from './rpc'
 
-const suppressWarningsPath = resolve(rootDir, './suppress-warnings.cjs')
-
 function createWorkerChannel(project: TestProject, collect: boolean) {
   const channel = new MessageChannel()
   const port = channel.port2
@@ -85,10 +82,7 @@ export function createVmThreadsPool(
 
     env,
     execArgv: [
-      '--experimental-import-meta-resolve',
       '--experimental-vm-modules',
-      '--require',
-      suppressWarningsPath,
       ...(poolOptions.execArgv ?? []),
       ...execArgv,
     ],

packages/vitest/src/runtime/moduleRunner/moduleRunner.ts

@@ -10,12 +10,35 @@ import * as viteModuleRunner from 'vite/module-runner'
 import { VitestMocker } from './moduleMocker'
 import { VitestTransport } from './moduleTransport'
 
-// eslint-disable-next-line ts/ban-ts-comment
-// @ts-ignore available since Vite 7.1 https://github.com/vitejs/vite/pull/20260
 export type CreateImportMeta = NonNullable<viteModuleRunner.ModuleRunnerOptions['createImportMeta']>
-// eslint-disable-next-line ts/ban-ts-comment
-// @ts-ignore
-export const createNodeImportMeta: CreateImportMeta = viteModuleRunner.createNodeImportMeta
+export const createNodeImportMeta: CreateImportMeta = (modulePath: string) => {
+  if (!viteModuleRunner.createDefaultImportMeta) {
+    throw new Error(`createNodeImportMeta is not supported in this version of Vite.`)
+  }
+
+  const defaultMeta = viteModuleRunner.createDefaultImportMeta(modulePath)
+  const href = defaultMeta.url
+
+  const importMetaResolver = createImportMetaResolver()
+
+  return {
+    ...defaultMeta,
+    main: false,
+    resolve(id: string, parent?: string) {
+      const resolver = importMetaResolver ?? defaultMeta.resolve
+      return resolver(id, parent ?? href)
+    },
+  }
+}
+
+function createImportMetaResolver() {
+  if (!import.meta.resolve) {
+    return
+  }
+
+  return (specifier: string, importer: string) =>
+    import.meta.resolve(specifier, importer)
+}
 
 // @ts-expect-error overriding private method
 export class VitestModuleRunner extends viteModuleRunner.ModuleRunner {
@@ -32,8 +55,6 @@ export class VitestModuleRunner extends viteModuleRunner.ModuleRunner {
         hmr: false,
         evaluatedModules,
         sourcemapInterceptor: 'prepareStackTrace',
-        // eslint-disable-next-line ts/ban-ts-comment
-        // @ts-ignore
         createImportMeta: vitestOptions.createImportMeta,
       },
       options.evaluator,
@@ -68,10 +89,7 @@ export class VitestModuleRunner extends viteModuleRunner.ModuleRunner {
 
   public async import(rawId: string): Promise<any> {
     const resolved = await this.vitestOptions.transport.resolveId(rawId)
-    if (!resolved) {
-      return super.import(rawId)
-    }
-    return super.import(resolved.url)
+    return super.import(resolved ? resolved.url : rawId)
   }
 
   public async fetchModule(url: string, importer?: string): Promise<EvaluatedModuleNode> {

packages/vitest/src/runtime/moduleRunner/startModuleRunner.ts

@@ -166,9 +166,6 @@ export function startVitestModuleRunner(options: ContextModuleRunnerOptions): Vi
     createImportMeta: options.createImportMeta,
   })
 
-  // await moduleRunner.import('/@vite/env')
-  // await moduleRunner.mocker.initializeSpyModule()
-
   return moduleRunner
 }