test(rsc): test stable client chunks

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

@@ -2,9 +2,16 @@ import assert from 'node:assert'
 import rsc, { transformHoistInlineDirective } from '@vitejs/plugin-rsc'
 import tailwindcss from '@tailwindcss/vite'
 import react from '@vitejs/plugin-react'
-import { type Plugin, defineConfig, normalizePath, parseAstAsync } from 'vite'
+import {
+  type Plugin,
+  Rollup,
+  defineConfig,
+  normalizePath,
+  parseAstAsync,
+} from 'vite'
 import inspect from 'vite-plugin-inspect'
 import path from 'node:path'
+import { fileURLToPath } from 'node:url'
 
 // log unhandled rejection to debug e2e failures
 if (!(globalThis as any).__debugHandlerRegisterd) {
@@ -104,6 +111,76 @@ export default defineConfig({
         }
       },
     },
+    {
+      name: 'optimize-chunks',
+      apply: 'build',
+      config() {
+        const resolvePackageSource = (source: string) =>
+          normalizePath(fileURLToPath(import.meta.resolve(source)))
+
+        // TODO: this entrypoint shouldn't be a public API.
+        const pkgBrowserPath = resolvePackageSource(
+          '@vitejs/plugin-rsc/react/browser',
+        )
+
+        return {
+          environments: {
+            client: {
+              build: {
+                rollupOptions: {
+                  output: {
+                    manualChunks: (id) => {
+                      // need to use functional form to handle commonjs plugin proxy module
+                      // e.g. `(id)?commonjs-es-import`
+                      if (
+                        id.includes('node_modules/react/') ||
+                        id.includes('node_modules/react-dom/') ||
+                        id.includes(pkgBrowserPath)
+                      ) {
+                        return 'lib-react'
+                      }
+                      if (id === '\0vite/preload-helper.js') {
+                        return 'lib-vite'
+                      }
+                    },
+                  },
+                },
+              },
+            },
+          },
+        }
+      },
+      // verify chunks are "stable"
+      writeBundle(_options, bundle) {
+        if (this.environment.name === 'client') {
+          const entryChunks: Rollup.OutputChunk[] = []
+          const vendorChunks: Rollup.OutputChunk[] = []
+          for (const chunk of Object.values(bundle)) {
+            if (chunk.type === 'chunk') {
+              if (chunk.facadeModuleId?.endsWith('/src/client.tsx')) {
+                entryChunks.push(chunk)
+              } else if (chunk.name === 'lib-react') {
+                vendorChunks.push(chunk)
+              }
+            }
+          }
+
+          // react vendor chunk has no import
+          assert.equal(vendorChunks.length, 1)
+          assert.deepEqual(
+            vendorChunks[0].imports.filter(
+              (f) => !f.includes('rolldown-runtime'),
+            ),
+            [],
+          )
+          assert.deepEqual(vendorChunks[0].dynamicImports, [])
+
+          // entry chunk has no export
+          assert.equal(entryChunks.length, 1)
+          assert.deepEqual(entryChunks[0].exports, [])
+        }
+      },
+    },
     {
       name: 'cf-build',
       enforce: 'post',