fix(ssr): handle uninitialized export access as undefined (#19959)

Author: hi-ogawa

packages/vite/src/node/ssr/__tests__/ssrLoadModule.spec.ts

@@ -235,7 +235,7 @@ test('json', async () => {
     null,
     '/test.json',
   )
-  expect(json?.code.length).toMatchInlineSnapshot(`208`)
+  expect(json?.code.length).toMatchInlineSnapshot(`225`)
 })
 
 test('file url', async () => {

packages/vite/src/node/ssr/__tests__/ssrTransform.spec.ts

@@ -55,7 +55,7 @@ test('export function declaration', async () => {
     await ssrTransformSimpleCode(`export function foo() {}`),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ return foo }});
+    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ try { return foo } catch {} }});
     function foo() {}"
   `,
   )
@@ -66,7 +66,7 @@ test('export class declaration', async () => {
     await ssrTransformSimpleCode(`export class foo {}`),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ return foo }});
+    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ try { return foo } catch {} }});
     class foo {}"
   `,
   )
@@ -77,8 +77,8 @@ test('export var declaration', async () => {
     await ssrTransformSimpleCode(`export const a = 1, b = 2`),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "a", { enumerable: true, configurable: true, get(){ return a }});
-    Object.defineProperty(__vite_ssr_exports__, "b", { enumerable: true, configurable: true, get(){ return b }});
+    "Object.defineProperty(__vite_ssr_exports__, "a", { enumerable: true, configurable: true, get(){ try { return a } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "b", { enumerable: true, configurable: true, get(){ try { return b } catch {} }});
     const a = 1, b = 2"
   `,
   )
@@ -89,8 +89,8 @@ test('export named', async () => {
     await ssrTransformSimpleCode(`const a = 1, b = 2; export { a, b as c }`),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "a", { enumerable: true, configurable: true, get(){ return a }});
-    Object.defineProperty(__vite_ssr_exports__, "c", { enumerable: true, configurable: true, get(){ return b }});
+    "Object.defineProperty(__vite_ssr_exports__, "a", { enumerable: true, configurable: true, get(){ try { return a } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "c", { enumerable: true, configurable: true, get(){ try { return b } catch {} }});
     const a = 1, b = 2; "
   `,
   )
@@ -101,8 +101,8 @@ test('export named from', async () => {
     await ssrTransformSimpleCode(`export { ref, computed as c } from 'vue'`),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "ref", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_0__.ref }});
-    Object.defineProperty(__vite_ssr_exports__, "c", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_0__.computed }});
+    "Object.defineProperty(__vite_ssr_exports__, "ref", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_0__.ref } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "c", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_0__.computed } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("vue", {"importedNames":["ref","computed"]});"
   `,
   )
@@ -115,7 +115,7 @@ test('named exports of imported binding', async () => {
     ),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "createApp", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_0__.createApp }});
+    "Object.defineProperty(__vite_ssr_exports__, "createApp", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_0__.createApp } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("vue", {"importedNames":["createApp"]});"
   `,
   )
@@ -139,7 +139,7 @@ test('export * as from', async () => {
     await ssrTransformSimpleCode(`export * as foo from 'vue'`),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_0__ }});
+    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_0__ } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("vue");"
   `,
   )
@@ -152,7 +152,7 @@ import * as foo from 'foo'
 export * as foo from 'foo'
 `),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_1__ }});
+    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_1__ } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("foo");
     const __vite_ssr_import_1__ = await __vite_ssr_import__("foo");
     "
@@ -164,7 +164,7 @@ import { foo } from 'foo'
 export { foo } from 'foo'
 `),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_1__.foo }});
+    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_1__.foo } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("foo", {"importedNames":["foo"]});
     const __vite_ssr_import_1__ = await __vite_ssr_import__("foo", {"importedNames":["foo"]});
     "
@@ -176,7 +176,7 @@ import { foo } from 'foo'
 export { foo as foo } from 'foo'
 `),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_1__.foo }});
+    "Object.defineProperty(__vite_ssr_exports__, "foo", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_1__.foo } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("foo", {"importedNames":["foo"]});
     const __vite_ssr_import_1__ = await __vite_ssr_import__("foo", {"importedNames":["foo"]});
     "
@@ -188,7 +188,7 @@ test('export * as from arbitrary module namespace identifier', async () => {
     await ssrTransformSimpleCode(`export * as "arbitrary string" from 'vue'`),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "arbitrary string", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_0__ }});
+    "Object.defineProperty(__vite_ssr_exports__, "arbitrary string", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_0__ } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("vue");"
   `,
   )
@@ -201,7 +201,7 @@ test('export as arbitrary module namespace identifier', async () => {
     ),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "arbitrary string", { enumerable: true, configurable: true, get(){ return something }});
+    "Object.defineProperty(__vite_ssr_exports__, "arbitrary string", { enumerable: true, configurable: true, get(){ try { return something } catch {} }});
     const something = "Something";"
   `,
   )
@@ -214,7 +214,7 @@ test('export as from arbitrary module namespace identifier', async () => {
     ),
   ).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "arbitrary string", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_0__["arbitrary string2"] }});
+    "Object.defineProperty(__vite_ssr_exports__, "arbitrary string", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_0__["arbitrary string2"] } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("vue", {"importedNames":["arbitrary string2"]});"
   `,
   )
@@ -223,9 +223,9 @@ test('export as from arbitrary module namespace identifier', async () => {
 test('export default', async () => {
   expect(await ssrTransformSimpleCode(`export default {}`))
     .toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return __vite_ssr_export_default__ }});
-    const __vite_ssr_export_default__ = {}"
-  `)
+      "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_export_default__ } catch {} }});
+      const __vite_ssr_export_default__ = {}"
+    `)
 })
 
 test('export then import minified', async () => {
@@ -347,7 +347,7 @@ test('dynamic import', async () => {
   )
   expect(result?.code).toMatchInlineSnapshot(
     `
-    "Object.defineProperty(__vite_ssr_exports__, "i", { enumerable: true, configurable: true, get(){ return i }});
+    "Object.defineProperty(__vite_ssr_exports__, "i", { enumerable: true, configurable: true, get(){ try { return i } catch {} }});
     const i = () => __vite_ssr_dynamic_import__('./foo')"
   `,
   )
@@ -507,8 +507,8 @@ test('should declare variable for imported super class', async () => {
         `export class B extends Foo {}`,
     ),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return A }});
-    Object.defineProperty(__vite_ssr_exports__, "B", { enumerable: true, configurable: true, get(){ return B }});
+    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return A } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "B", { enumerable: true, configurable: true, get(){ try { return B } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("./dependency", {"importedNames":["Foo"]});const Foo = __vite_ssr_import_0__.Foo;
     class A extends Foo {};
     class B extends Foo {}"
@@ -520,14 +520,14 @@ test('should handle default export variants', async () => {
   // default anonymous functions
   expect(await ssrTransformSimpleCode(`export default function() {}\n`))
     .toMatchInlineSnapshot(`
-      "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return __vite_ssr_export_default__ }});
+      "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_export_default__ } catch {} }});
       const __vite_ssr_export_default__ = function() {}
       "
     `)
   // default anonymous class
   expect(await ssrTransformSimpleCode(`export default class {}\n`))
     .toMatchInlineSnapshot(`
-      "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return __vite_ssr_export_default__ }});
+      "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_export_default__ } catch {} }});
       const __vite_ssr_export_default__ = class {}
       "
     `)
@@ -538,7 +538,7 @@ test('should handle default export variants', async () => {
         `foo.prototype = Object.prototype;`,
     ),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return foo }});
+    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return foo } catch {} }});
     function foo() {};
     foo.prototype = Object.prototype;"
   `)
@@ -548,8 +548,8 @@ test('should handle default export variants', async () => {
       `export default class A {}\n` + `export class B extends A {}`,
     ),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return A }});
-    Object.defineProperty(__vite_ssr_exports__, "B", { enumerable: true, configurable: true, get(){ return B }});
+    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return A } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "B", { enumerable: true, configurable: true, get(){ try { return B } catch {} }});
     class A {};
     class B extends A {}"
   `)
@@ -988,8 +988,8 @@ export function fn1() {
         `,
     ),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "fn1", { enumerable: true, configurable: true, get(){ return fn1 }});
-    Object.defineProperty(__vite_ssr_exports__, "fn2", { enumerable: true, configurable: true, get(){ return fn2 }});
+    "Object.defineProperty(__vite_ssr_exports__, "fn1", { enumerable: true, configurable: true, get(){ try { return fn1 } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "fn2", { enumerable: true, configurable: true, get(){ try { return fn2 } catch {} }});
 
     function fn1() {
     };function fn2() {
@@ -1011,17 +1011,17 @@ export default (function getRandom() {
 `.trim()
 
   expect(await ssrTransformSimpleCode(code)).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return __vite_ssr_export_default__ }});
+    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_export_default__ } catch {} }});
     const __vite_ssr_export_default__ = (function getRandom() {
       return Math.random();
     });"
   `)
 
   expect(await ssrTransformSimpleCode(`export default (class A {});`))
     .toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return __vite_ssr_export_default__ }});
-    const __vite_ssr_export_default__ = (class A {});"
-  `)
+      "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_export_default__ } catch {} }});
+      const __vite_ssr_export_default__ = (class A {});"
+    `)
 })
 
 // #8002
@@ -1095,7 +1095,7 @@ export class Test {
 };`.trim()
 
   expect(await ssrTransformSimpleCode(code)).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "Test", { enumerable: true, configurable: true, get(){ return Test }});
+    "Object.defineProperty(__vite_ssr_exports__, "Test", { enumerable: true, configurable: true, get(){ try { return Test } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("foobar", {"importedNames":["foo","bar"]});
     if (false) {
       const foo = 'foo';
@@ -1285,8 +1285,8 @@ export * as bar from './bar'
 console.log(bar)
   `),
   ).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ return __vite_ssr_export_default__ }});
-    Object.defineProperty(__vite_ssr_exports__, "bar", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_1__ }});
+    "Object.defineProperty(__vite_ssr_exports__, "default", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_export_default__ } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "bar", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_1__ } catch {} }});
 
     const __vite_ssr_import_0__ = await __vite_ssr_import__("./foo", {"importedNames":["foo"]});const __vite_ssr_import_1__ = await __vite_ssr_import__("./bar");;
     const __vite_ssr_export_default__ = (0,__vite_ssr_import_0__.foo)();
@@ -1542,9 +1542,9 @@ import("e")
 export * as A from "a";
 `)
   expect(result?.code).toMatchInlineSnapshot(`
-    "Object.defineProperty(__vite_ssr_exports__, "b", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_1__.b }});
-    Object.defineProperty(__vite_ssr_exports__, "d", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_3__ }});
-    Object.defineProperty(__vite_ssr_exports__, "A", { enumerable: true, configurable: true, get(){ return __vite_ssr_import_4__ }});
+    "Object.defineProperty(__vite_ssr_exports__, "b", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_1__.b } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "d", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_3__ } catch {} }});
+    Object.defineProperty(__vite_ssr_exports__, "A", { enumerable: true, configurable: true, get(){ try { return __vite_ssr_import_4__ } catch {} }});
     const __vite_ssr_import_0__ = await __vite_ssr_import__("a", {"importedNames":["default"]});
     const __vite_ssr_import_1__ = await __vite_ssr_import__("b", {"importedNames":["b"]});
     const __vite_ssr_import_2__ = await __vite_ssr_import__("c");__vite_ssr_exportAll__(__vite_ssr_import_2__);

packages/vite/src/node/ssr/runtime/__tests__/server-runtime.spec.ts

@@ -290,15 +290,20 @@ describe('module runner initialization', async () => {
     await expect(() =>
       runner.import('/fixtures/cyclic2/test5/index.js'),
     ).rejects.toMatchInlineSnapshot(
-      `[ReferenceError: Cannot access '__vite_ssr_import_1__' before initialization]`,
+      `[TypeError: Cannot read properties of undefined (reading 'ok')]`,
     )
   })
 
   it(`cyclic invalid 2`, async ({ runner }) => {
-    await expect(() =>
-      runner.import('/fixtures/cyclic2/test6/index.js'),
-    ).rejects.toMatchInlineSnapshot(
-      `[ReferenceError: Cannot access 'dep1' before initialization]`,
+    // It should be an error but currently `undefined` fallback.
+    expect(
+      await runner.import('/fixtures/cyclic2/test6/index.js'),
+    ).toMatchInlineSnapshot(
+      `
+      {
+        "dep1": "dep1: dep2: undefined",
+      }
+    `,
     )
   })
 
@@ -374,10 +379,15 @@ describe('module runner initialization', async () => {
 
   it(`export default getter is hoisted`, async ({ runner }) => {
     // Node error is `ReferenceError: Cannot access 'dep' before initialization`
-    await expect(() =>
-      runner.import('/fixtures/cyclic2/test9/index.js'),
-    ).rejects.toMatchInlineSnapshot(
-      `[ReferenceError: Cannot access '__vite_ssr_export_default__' before initialization]`,
+    // It should be an error but currently `undefined` fallback.
+    expect(
+      await runner.import('/fixtures/cyclic2/test9/index.js'),
+    ).toMatchInlineSnapshot(
+      `
+      {
+        "default": undefined,
+      }
+    `,
     )
   })
 })

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

@@ -179,10 +179,11 @@ async function ssrTransformScript(
   }
 
   function defineExport(name: string, local = name) {
+    // wrap with try/catch to fallback to `undefined` for backward compat.
     s.appendLeft(
       fileStartIndex,
       `Object.defineProperty(${ssrModuleExportsKey}, ${JSON.stringify(name)}, ` +
-        `{ enumerable: true, configurable: true, get(){ return ${local} }});\n`,
+        `{ enumerable: true, configurable: true, get(){ try { return ${local} } catch {} }});\n`,
     )
   }
 

vitest.config.ts

@@ -19,10 +19,6 @@ export default defineConfig({
     },
     testTimeout: 20000,
     isolate: false,
-    // importing non-entry files (e.g. config.ts, build.ts, server/index.ts) is broken due to cyclic import
-    // as it can be seen from tsx (try pnpm exec tsx packages/vite/src/node/server/index.ts).
-    // we can use `setupFiles` to ensure the modules are evaluated via main node entry.
-    setupFiles: ['./packages/vite/src/node/index.ts'],
   },
   esbuild: {
     target: 'node18',