fix(rsc): fix build error when entire client reference module is tree-shaken (#827)

Author: hi-ogawa

packages/plugin-rsc/e2e/basic.test.ts

@@ -1454,4 +1454,12 @@ function defineTest(f: Fixture) {
       'test-chunk1|test-chunk2|test-chunk2b|test-chunk3|test-chunk3',
     )
   })
+
+  test('tree-shake2', async ({ page }) => {
+    await page.goto(f.url())
+    await waitForHydration(page)
+    await expect(page.getByTestId('test-tree-shake2')).toHaveText(
+      'test-tree-shake2:lib-client1|lib-server1',
+    )
+  })
 }

packages/plugin-rsc/examples/basic/src/routes/root.tsx

@@ -39,6 +39,7 @@ import { TestAssetsServer } from './assets/server'
 import { TestHmrSwitchServer } from './hmr-switch/server'
 import { TestHmrSwitchClient } from './hmr-switch/client'
 import { TestTreeShakeServer } from './tree-shake/server'
+import { TestTreeShake2 } from './tree-shake2/server'
 import { TestClientChunkServer } from './chunk/server'
 import { TestTailwind } from './tailwind'
 import { TestHmrClientDep2 } from './hmr-client-dep2/client'
@@ -100,6 +101,7 @@ export function Root(props: { url: URL }) {
         <TestImportMetaGlob />
         <TestAssetsServer />
         <TestTreeShakeServer />
+        <TestTreeShake2 />
         <TestClientChunkServer />
         <TestChunk2 />
         <TestUseId />

packages/plugin-rsc/examples/basic/src/routes/tree-shake2/lib-client1.tsx

@@ -0,0 +1,5 @@
+'use client'
+
+export function LibClient1() {
+  return 'lib-client1'
+}

packages/plugin-rsc/examples/basic/src/routes/tree-shake2/lib-client2.tsx

@@ -0,0 +1,5 @@
+'use client'
+
+export function LibClient2() {
+  return 'lib-client2:__unused_tree_shake2__'
+}

packages/plugin-rsc/examples/basic/src/routes/tree-shake2/lib-server1.tsx

@@ -0,0 +1,3 @@
+export function LibServer1() {
+  return 'lib-server1'
+}

packages/plugin-rsc/examples/basic/src/routes/tree-shake2/lib-server2.tsx

@@ -0,0 +1,3 @@
+export function LibServer2() {
+  return 'lib-server2:__unused_tree_shake2__'
+}

packages/plugin-rsc/examples/basic/src/routes/tree-shake2/lib.tsx

@@ -0,0 +1,4 @@
+export * from './lib-client1'
+export * from './lib-client2'
+export * from './lib-server1'
+export * from './lib-server2'

packages/plugin-rsc/examples/basic/src/routes/tree-shake2/server.tsx

@@ -0,0 +1,10 @@
+import { LibClient1, LibServer1 } from './lib'
+
+export function TestTreeShake2() {
+  return (
+    <div data-testid="test-tree-shake2">
+      test-tree-shake2:
+      <LibClient1 />|<LibServer1 />
+    </div>
+  )
+}

packages/plugin-rsc/examples/basic/vite.config.ts

@@ -47,6 +47,7 @@ export default defineConfig({
           if (chunk.type === 'chunk') {
             assert(!chunk.code.includes('__unused_client_reference__'))
             assert(!chunk.code.includes('__unused_server_export__'))
+            assert(!chunk.code.includes('__unused_tree_shake2__'))
           }
         }
       },

packages/plugin-rsc/src/plugin.ts

@@ -1226,12 +1226,14 @@ function vitePluginUseClient(
           // group client reference modules by `clientChunks` option
           manager.clientReferenceGroups = {}
           for (const meta of Object.values(manager.clientReferenceMetaMap)) {
+            // no server chunk is associated when the entire "use client" module is tree-shaken
+            if (!meta.serverChunk) continue
             let name =
               useClientPluginOptions.clientChunks?.({
                 id: meta.importId,
                 normalizedId: manager.toRelativeId(meta.importId),
-                serverChunk: meta.serverChunk!,
-              }) ?? meta.serverChunk!
+                serverChunk: meta.serverChunk,
+              }) ?? meta.serverChunk
             // ensure clean virtual id to avoid interfering with other plugins
             name = cleanUrl(name.replaceAll('..', '__'))
             const group = (manager.clientReferenceGroups[name] ??= [])
@@ -1333,6 +1335,7 @@ function vitePluginUseClient(
         }
       },
       generateBundle(_options, bundle) {
+        if (manager.isScanBuild) return
         if (this.environment.name !== serverEnvironmentName) return
 
         // analyze rsc build to inform later client reference building.