fix(rsc): preserve server manifest export names

Author: james-elicx

packages/plugin-rsc/src/plugin.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from 'vitest'
+import { vitePluginRscMinimal } from './plugin'
+
+describe('server reference manifest', () => {
+  it('preserves and deduplicates existing export names', async () => {
+    const plugins = vitePluginRscMinimal({ enableActionEncryption: false })
+    const minimalPlugin = plugins.find(
+      (plugin) => plugin.name === 'rsc:minimal',
+    )!
+    const manager = (minimalPlugin.api as any).manager
+    manager.config = {
+      command: 'build',
+      root: '/root',
+    }
+
+    const id = '/root/actions.ts'
+    manager.serverReferenceMetaMap[id] = {
+      importId: id,
+      referenceKey: 'existing',
+      exportNames: ['cached', 'action', 'cached'],
+    }
+
+    const useServerPlugin = plugins.find(
+      (plugin) => plugin.name === 'rsc:use-server',
+    )!
+    const transformHandler = (useServerPlugin.transform as any).handler
+    await transformHandler.call(
+      {
+        environment: { name: 'rsc', mode: 'build' },
+        error(error: unknown) {
+          throw error
+        },
+      },
+      `"use server"; export async function action() {}`,
+      id,
+    )
+
+    expect(manager.serverReferenceMetaMap[id].exportNames).toEqual([
+      'cached',
+      'action',
+    ])
+
+    const manifestPlugin = plugins.find(
+      (plugin) => plugin.name === 'rsc:virtual-vite-rsc/server-references',
+    )!
+    const loadHandler = (manifestPlugin.load as any).handler
+    const manifest = await loadHandler.call(
+      { environment: { mode: 'build' } },
+      '\0virtual:vite-rsc/server-references',
+      {},
+    )
+
+    expect(manifest.code.match(/\bcached\b/g)).toHaveLength(2)
+    expect(manifest.code.match(/\baction\b/g)).toHaveLength(2)
+  })
+})

packages/plugin-rsc/src/plugin.ts

@@ -2017,11 +2017,16 @@ function vitePluginUseServer(
               delete manager.serverReferenceMetaMap[id]
               return
             }
+            const existingExportNames =
+              manager.serverReferenceMetaMap[id]?.exportNames ?? []
+            const exportNames =
+              'names' in result ? result.names : result.exportNames
             manager.serverReferenceMetaMap[id] = {
               importId: id,
               referenceKey: getNormalizedId(),
-              exportNames:
-                'names' in result ? result.names : result.exportNames,
+              exportNames: [
+                ...new Set([...existingExportNames, ...exportNames]),
+              ],
             }
             const importSource = resolvePackage(`${PKG_NAME}/react/rsc`)
             output.prepend(
@@ -2094,7 +2099,7 @@ function vitePluginUseServer(
       for (const meta of Object.values(manager.serverReferenceMetaMap)) {
         const key = JSON.stringify(meta.referenceKey)
         const id = JSON.stringify(meta.importId)
-        const exports = meta.exportNames
+        const exports = [...new Set(meta.exportNames)]
           .map((name) => (name === 'default' ? 'default: _default' : name))
           .sort()
         code += `