Fix conflict when re-exporting multiple Client References (#49468)

Closes #49324. Default export should only be added in the loader
generated boundary file when it actually exists.

fix NEXT-1112

packages/next-swc/crates/core/src/react_server_components.rs

@@ -247,6 +247,12 @@ impl<C: Comments> ReactServerComponents<C> {
                 })) => {
                     self.export_names.push("default".to_string());
                 }
+                ModuleItem::ModuleDecl(ModuleDecl::ExportDefaultExpr(ExportDefaultExpr {
+                    expr: _,
+                    ..
+                })) => {
+                    self.export_names.push("default".to_string());
+                }
                 ModuleItem::ModuleDecl(ModuleDecl::ExportAll(_)) => {
                     self.export_names.push("*".to_string());
                 }

packages/next/src/build/webpack/loaders/next-flight-loader/index.ts

@@ -70,17 +70,21 @@ const proxy = createProxy(String.raw\`${this.resourcePath}\`)
 // The __esModule getter forces the proxy target to create the default export
 // and the $$typeof value is for rendering logic to determine if the module
 // is a client boundary.
-export const { __esModule, $$typeof } = proxy;
-export default proxy.default;
+const { __esModule, $$typeof } = proxy;
+const __default__ = proxy.default;
 `
       let cnt = 0
       for (const ref of clientRefs) {
-        if (ref !== '' && ref !== 'default') {
+        if (ref === '') {
+          esmSource += `\nexports[''] = proxy[''];`
+        } else if (ref === 'default') {
+          esmSource += `
+export { __esModule, $$typeof };
+export default __default__;`
+        } else {
           esmSource += `
 const e${cnt} = proxy["${ref}"];
 export { e${cnt++} as ${ref} };`
-        } else if (ref === '') {
-          esmSource += `\nexports[''] = proxy[''];`
         }
       }
 

test/e2e/app-dir/app-external/app-external.test.ts

@@ -183,6 +183,11 @@ createNextDescribe(
       expect(html).toContain('hello')
     })
 
+    it('should support exporting multiple star re-exports', async () => {
+      const html = await next.render('/wildcard')
+      expect(html).toContain('Foo')
+    })
+
     if ((global as any).isNextDev) {
       it('should error for wildcard exports of client module references in esm', async () => {
         const page = 'app/esm-client-ref/page.js'

test/e2e/app-dir/app-external/app/wildcard/page.js

@@ -0,0 +1,5 @@
+import { Foo } from 'client-esm-module-wildcard-2'
+
+export default function Page() {
+  return <Foo />
+}

test/e2e/app-dir/app-external/node_modules_bak/client-esm-module-wildcard-2/bar.js

@@ -0,0 +1,5 @@
+'use client'
+
+export function Bar() {
+  return 'Bar'
+}

test/e2e/app-dir/app-external/node_modules_bak/client-esm-module-wildcard-2/foo.js

@@ -0,0 +1,5 @@
+'use client'
+
+export function Foo() {
+  return 'Foo'
+}

test/e2e/app-dir/app-external/node_modules_bak/client-esm-module-wildcard-2/index.js

@@ -0,0 +1,2 @@
+export * from './foo'
+export * from './bar'

test/e2e/app-dir/app-external/node_modules_bak/client-esm-module-wildcard-2/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "client-esm-module-wildcard-2",
+  "type": "module",
+  "exports": {
+    "default": "./index.js"
+  }
+}