test: add tests for inlineImport

packages/vite/src/node/__tests__/fixtures/inline-import/basic.ts

@@ -0,0 +1,7 @@
+interface Test {
+  field: true
+}
+
+export const test: Test = {
+  field: true,
+}

packages/vite/src/node/__tests__/fixtures/inline-import/cjs.js

@@ -0,0 +1 @@
+module.exports = {}

packages/vite/src/node/__tests__/fixtures/inline-import/plugin.ts

@@ -0,0 +1,7 @@
+import { Plugin } from 'vite'
+
+export default function testPlugin(): Plugin {
+  return {
+    name: 'test',
+  }
+}

packages/vite/src/node/__tests__/fixtures/inline-import/vite.config.ts

@@ -0,0 +1,7 @@
+import { defineConfig } from 'vite'
+import plugin from './plugin'
+
+export default defineConfig({
+  root: './test',
+  plugins: [plugin()],
+})

packages/vite/src/node/__tests__/inlineImport.spec.ts

@@ -0,0 +1,40 @@
+import { resolve } from 'node:path'
+import { describe, expect, test } from 'vitest'
+import { inlineImport } from '../ssr/inlineImport'
+
+describe('importing files using inlined environment', () => {
+  const fixture = (name: string) =>
+    resolve(import.meta.dirname, './fixtures/inline-import', name)
+
+  test('importing a basic file works', async () => {
+    const { module } = await inlineImport<
+      typeof import('./fixtures/inline-import/basic')
+    >(fixture('basic'))
+    expect(module.test).toEqual({
+      field: true,
+    })
+  })
+
+  test("cannot import cjs, 'inlineImport' doesn't support CJS syntax at all", async () => {
+    await expect(() =>
+      inlineImport<typeof import('./fixtures/inline-import/basic')>(
+        fixture('cjs.js'),
+      ),
+    ).rejects.toThrow('module is not defined')
+  })
+
+  test('can import vite config', async () => {
+    const { module, dependencies } = await inlineImport<
+      typeof import('./fixtures/inline-import/vite.config')
+    >(fixture('vite.config'))
+    expect(module.default).toEqual({
+      root: './test',
+      plugins: [
+        {
+          name: 'test',
+        },
+      ],
+    })
+    expect(dependencies).toEqual([fixture('plugin.ts')])
+  })
+})

packages/vite/src/node/config.ts

@@ -98,7 +98,7 @@ import type { ResolvedSSROptions, SSROptions } from './ssr'
 import { resolveSSROptions, ssrConfigDefaults } from './ssr'
 import { PartialEnvironment } from './baseEnvironment'
 import { createIdResolver } from './idResolver'
-import { inlineImport } from './ssr/import'
+import { inlineImport } from './ssr/inlineImport'
 
 const debug = createDebugger('vite:config', { depth: 10 })
 const promisifiedRealpath = promisify(fs.realpath)
@@ -1697,7 +1697,9 @@ export async function loadConfigFromFile(
 }
 
 async function importConfigFile(resolvedPath: string) {
-  const { module, dependencies } = await inlineImport(resolvedPath)
+  const { module, dependencies } = await inlineImport<{
+    default: UserConfigExport
+  }>(resolvedPath, { configFile: false })
   return {
     configExport: module.default,
     dependencies,

packages/vite/src/node/index.ts

@@ -31,6 +31,7 @@ export {
   DevEnvironment,
   type DevEnvironmentContext,
 } from './server/environment'
+export { inlineImport } from './ssr/inlineImport'
 export { BuildEnvironment } from './build'
 
 export { fetchModule, type FetchModuleOptions } from './ssr/fetchModule'

packages/vite/src/node/ssr/import.ts → packages/vite/src/node/ssr/inlineImport.ts

@@ -1,20 +1,26 @@
+import type { InlineConfig } from '../config'
 import { resolveConfig } from '../config'
 import { createRunnableDevEnvironment } from '../server/environments/runnableEnvironment'
+import { mergeConfig } from '../utils'
 
-interface InlineImportResult {
-  module: any
+interface InlineImportResult<T> {
+  module: T
   dependencies: string[]
 }
 
-export async function inlineImport(
+/**
+ * Import any file using the default Vite environment.
+ * @experimental
+ */
+export async function inlineImport<T>(
   moduleId: string,
-): Promise<InlineImportResult> {
+  inlineConfig?: InlineConfig,
+): Promise<InlineImportResult<T>> {
   const environment = createRunnableDevEnvironment(
     'inline',
     // TODO: provide a dummy config?
     await resolveConfig(
-      {
-        configFile: false,
+      mergeConfig(inlineConfig || {}, {
         environments: {
           inline: {
             consumer: 'server',
@@ -26,7 +32,7 @@ export async function inlineImport(
             },
           },
         },
-      },
+      }),
       'serve',
     ),
     {
@@ -42,16 +48,18 @@ export async function inlineImport(
   try {
     const module = await environment.runner.import(moduleId)
     const modules = [
-      ...environment.runner.evaluatedModules.fileToModulesMap.entries(),
+      ...environment.runner.evaluatedModules.urlToIdModuleMap.values(),
     ]
     const dependencies = modules
-      .filter(([file, modules]) => {
-        const isExternal = [...modules].every(
-          (m) => !m.meta || 'externalize' in m.meta,
-        )
-        return !isExternal && file !== moduleId
+      .filter((m) => {
+        // ignore all externalized modules
+        if (!m.meta || 'externalize' in m.meta) {
+          return false
+        }
+        // ignore the current module
+        return m.exports !== module
       })
-      .map(([file]) => file)
+      .map((m) => m.file)
     return {
       module,
       dependencies,