fix: adjust import analysis behavior to match Node (#16738)

packages/vite/src/node/ssr/ssrModuleLoader.ts

@@ -16,7 +16,6 @@ import {
 import {
   type SSRImportBaseMetadata,
   analyzeImportedModDifference,
-  proxyGuardOnlyEsm,
 } from '../../shared/ssrTransform'
 import { SOURCEMAPPING_URL } from '../../shared/constants'
 import {
@@ -317,7 +316,7 @@ async function nodeImport(
         : undefined,
       metadata,
     )
-    return proxyGuardOnlyEsm(mod, id)
+    return mod
   } else {
     return mod
   }

packages/vite/src/runtime/runtime.ts

@@ -8,10 +8,7 @@ import {
   unwrapId,
   wrapId,
 } from '../shared/utils'
-import {
-  analyzeImportedModDifference,
-  proxyGuardOnlyEsm,
-} from '../shared/ssrTransform'
+import { analyzeImportedModDifference } from '../shared/ssrTransform'
 import { ModuleCacheMap } from './moduleCache'
 import type {
   FetchResult,
@@ -193,7 +190,7 @@ export class ViteRuntime {
     const { id, type } = fetchResult
     if (type !== 'module' && type !== 'commonjs') return exports
     analyzeImportedModDifference(exports, id, type, metadata)
-    return proxyGuardOnlyEsm(exports, id, metadata)
+    return exports
   }
 
   private async cachedRequest(

packages/vite/src/shared/ssrTransform.ts

@@ -28,48 +28,32 @@ export function analyzeImportedModDifference(
 ): void {
   // No normalization needed if the user already dynamic imports this module
   if (metadata?.isDynamicImport) return
-  // If file path is ESM, everything should be fine
-  if (moduleType === 'module') return
 
-  // For non-ESM, named imports is done via static analysis with cjs-module-lexer in Node.js.
   // If the user named imports a specifier that can't be analyzed, error.
+  // If the module doesn't import anything explicitly, e.g. `import 'foo'` or
+  // `import * as foo from 'foo'`, we can skip.
   if (metadata?.importedNames?.length) {
     const missingBindings = metadata.importedNames.filter((s) => !(s in mod))
     if (missingBindings.length) {
       const lastBinding = missingBindings[missingBindings.length - 1]
-      // Copied from Node.js
-      throw new SyntaxError(`\
+
+      // For invalid named exports only, similar to how Node.js errors for top-level imports.
+      // But since we transform as dynamic imports, we need to emulate the error manually.
+      if (moduleType === 'module') {
+        throw new SyntaxError(
+          `[vite] The requested module '${rawId}' does not provide an export named '${lastBinding}'`,
+        )
+      } else {
+        // For non-ESM, named imports is done via static analysis with cjs-module-lexer in Node.js.
+        // Copied from Node.js
+        throw new SyntaxError(`\
 [vite] Named export '${lastBinding}' not found. The requested module '${rawId}' is a CommonJS module, which may not support all module.exports as named exports.
 CommonJS modules can always be imported via the default export, for example using:
 
 import pkg from '${rawId}';
 const {${missingBindings.join(', ')}} = pkg;
 `)
+      }
     }
   }
 }
-
-/**
- * Guard invalid named exports only, similar to how Node.js errors for top-level imports.
- * But since we transform as dynamic imports, we need to emulate the error manually.
- */
-export function proxyGuardOnlyEsm(
-  mod: any,
-  rawId: string,
-  metadata?: SSRImportBaseMetadata,
-): any {
-  // If the module doesn't import anything explicitly, e.g. `import 'foo'` or
-  // `import * as foo from 'foo'`, we can skip the proxy guard.
-  if (!metadata?.importedNames?.length) return mod
-
-  return new Proxy(mod, {
-    get(mod, prop) {
-      if (prop !== 'then' && !(prop in mod)) {
-        throw new SyntaxError(
-          `[vite] The requested module '${rawId}' does not provide an export named '${prop.toString()}'`,
-        )
-      }
-      return mod[prop]
-    },
-  })
-}