Fix rsc bootstrap buffer missing in the future renders

packages/next/client/index.tsx

@@ -702,7 +702,9 @@ if (process.env.__NEXT_RSC) {
         writer.write(encoder.encode(val))
       })
       buffer.length = 0
-      serverDataBuffer.delete(key)
+      // Clean buffer but not deleting the key to mark bootstrap as complete.
+      // Then `nextServerDataCallback` will be safely skipped in the future renders.
+      serverDataBuffer.set(key, [])
     }
     serverDataWriter.set(key, writer)
   }

test/integration/react-streaming-and-server-components/app/next.config.js

@@ -1,6 +1,7 @@
 const withReact18 = require('../../react-18/test/with-react-18')
 
 module.exports = withReact18({
+  trailingSlash: true,
   reactStrictMode: true,
   onDemandEntries: {
     maxInactiveAge: 1000 * 60 * 60,

test/integration/react-streaming-and-server-components/app/pages/streaming-rsc.server.js

@@ -0,0 +1,23 @@
+import { Suspense } from 'react'
+
+let result
+let promise
+function Data() {
+  if (result) return result
+  if (!promise)
+    promise = new Promise((res) => {
+      setTimeout(() => {
+        result = 'next_streaming_data'
+        res()
+      }, 500)
+    })
+  throw promise
+}
+
+export default function Page() {
+  return (
+    <Suspense fallback="next_streaming_fallback">
+      <Data />
+    </Suspense>
+  )
+}

test/integration/react-streaming-and-server-components/test/rsc.js

@@ -82,6 +82,12 @@ export default function (context, { runtime, env }) {
     expect(await browser.eval('window.beforeNav')).toBe(1)
   })
 
+  it('should handle streaming server components correctly', async () => {
+    const browser = await webdriver(context.appPort, '/streaming-rsc')
+    const content = await browser.eval(`window.document.body.innerText`)
+    expect(content).toMatchInlineSnapshot('"next_streaming_data"')
+  })
+
   // Disable next/image for nodejs runtime temporarily
   if (runtime === 'edge') {
     it('should suspense next/image in server components', async () => {