From e90ff686550c05a43f89c0ca36d2a689c7222bf5 Mon Sep 17 00:00:00 2001
From: xiachao <achaozuiq>
Date: Tue, 25 Aug 2026 18:07:15 +0800
Subject: [PATCH] fix(ssr): throw on missing named exports in inlined modules

Vite-transformed SSR modules skipped analyzeImportedModDifference, so import { missing } from a local ESM file succeeded while Node throws SyntaxError. Run the same check after the module finishes evaluating, and skip it on incomplete circular graphs.

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 packages/vite/src/module-runner/runner.ts     | 21 ++++++++++++++-----
 .../fixtures/esm-internal-existing.js         |  3 +++
 .../fixtures/esm-internal-non-existing.js     |  3 +++
 .../runtime/__tests__/server-runtime.spec.ts  | 13 ++++++++++++
 4 files changed, 35 insertions(+), 5 deletions(-)
 create mode 100644 packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-existing.js
 create mode 100644 packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-non-existing.js

diff --git a/packages/vite/src/module-runner/runner.ts b/packages/vite/src/module-runner/runner.ts
index b975b0a436c0f9..b63f6071ef270b 100644
--- a/packages/vite/src/module-runner/runner.ts
+++ b/packages/vite/src/module-runner/runner.ts
@@ -123,13 +123,24 @@ export class ModuleRunner {
     exports: Record<string, any>,
     fetchResult: ResolvedResult,
     metadata?: SSRImportMetadata,
+    isCompleteModule = true,
   ) {
-    if (!('externalize' in fetchResult)) {
+    // Cyclic inlined graphs may return a partial exports object while the
+    // exporter is still evaluating. Named-export checks must wait until the
+    // module finished, matching Node (and avoiding false SyntaxErrors).
+    if (!isCompleteModule) {
       return exports
     }
-    const { url, type } = fetchResult
-    if (type !== 'module' && type !== 'commonjs') return exports
-    analyzeImportedModDifference(exports, url, type, metadata)
+    if ('externalize' in fetchResult) {
+      const { url, type } = fetchResult
+      if (type !== 'module' && type !== 'commonjs') return exports
+      analyzeImportedModDifference(exports, url, type, metadata)
+      return exports
+    }
+    // Vite-transformed modules are ESM. Previously this path skipped
+    // analyzeImportedModDifference entirely, so `import { missing }` from a
+    // local file did not throw (Node throws SyntaxError).
+    analyzeImportedModDifference(exports, fetchResult.url, 'module', metadata)
     return exports
   }
 
@@ -185,7 +196,7 @@ export class ModuleRunner {
         mod.exports &&
         (callstack.includes(moduleId) || this.isCircularRequest(mod, callstack))
       ) {
-        return this.processImport(mod.exports, meta, metadata)
+        return this.processImport(mod.exports, meta, metadata, false)
       }
       return this.processImport(await mod.promise, meta, metadata)
     }
diff --git a/packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-existing.js b/packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-existing.js
new file mode 100644
index 00000000000000..69402f59187c65
--- /dev/null
+++ b/packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-existing.js
@@ -0,0 +1,3 @@
+import { test } from './simple.js'
+
+export const result = test
diff --git a/packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-non-existing.js b/packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-non-existing.js
new file mode 100644
index 00000000000000..a952325c57c814
--- /dev/null
+++ b/packages/vite/src/node/ssr/runtime/__tests__/fixtures/esm-internal-non-existing.js
@@ -0,0 +1,3 @@
+import { nonExisting } from './simple.js'
+
+export const result = nonExisting
diff --git a/packages/vite/src/node/ssr/runtime/__tests__/server-runtime.spec.ts b/packages/vite/src/node/ssr/runtime/__tests__/server-runtime.spec.ts
index 79b474ab66a6f0..b6c346bc7f1f1d 100644
--- a/packages/vite/src/node/ssr/runtime/__tests__/server-runtime.spec.ts
+++ b/packages/vite/src/node/ssr/runtime/__tests__/server-runtime.spec.ts
@@ -200,6 +200,19 @@ describe('module runner initialization', async () => {
     })
   })
 
+  it('importing inlined esm module checks exports', async ({ runner }) => {
+    await expect(() =>
+      runner.import('/fixtures/esm-internal-non-existing.js'),
+    ).rejects.toThrowError(
+      `[vite] The requested module '/fixtures/simple.js' does not provide an export named 'nonExisting'`,
+    )
+    await expect(
+      runner.import('/fixtures/esm-internal-existing.js'),
+    ).resolves.toMatchObject({
+      result: 'I am initialized',
+    })
+  })
+
   it("dynamic import doesn't produce duplicates", async ({ runner }) => {
     const mod = await runner.import('/fixtures/dynamic-import.js')
     const modules = await mod.initialize()