From 990f928f5158ccf7f3e8fde1a61c9365284792bf Mon Sep 17 00:00:00 2001
From: Shu Ding <g@shud.in>
Date: Sun, 7 Nov 2021 03:40:25 +0100
Subject: [PATCH] fix id generation

---
 packages/next/server/render.tsx               | 44 ++++++++++++++++---
 test/integration/react-18/app/pages/use-id.js |  5 +++
 test/integration/react-18/test/basics.js      | 11 +++++
 3 files changed, 54 insertions(+), 6 deletions(-)
 create mode 100644 test/integration/react-18/app/pages/use-id.js

diff --git a/packages/next/server/render.tsx b/packages/next/server/render.tsx
index 53fa578287d73ab..3f11e124ef8921f 100644
--- a/packages/next/server/render.tsx
+++ b/packages/next/server/render.tsx
@@ -514,9 +514,9 @@ export async function renderToHTML(
     defaultLocale: renderOpts.defaultLocale,
     AppTree: (props: any) => {
       return (
-        <AppContainer>
+        <AppContainerWithIsomorphicFiberStructure>
           <App {...props} Component={Component} router={router} />
-        </AppContainer>
+        </AppContainerWithIsomorphicFiberStructure>
       )
     },
     defaultGetInitialProps: async (
@@ -577,6 +577,38 @@ export async function renderToHTML(
     </RouterContext.Provider>
   )
 
+  // The `useId` API uses the path indexes to generate an ID for each node.
+  // To guarantee the match of hydration, we need to ensure that the structure
+  // of wrapper nodes is isomorphic in server and client.
+  // TODO: With `enhanceApp` and `enhanceComponents` options, this approach may
+  // not be useful.
+  // https://github.com/facebook/react/pull/22644
+  const Noop = () => null
+  const AppContainerWithIsomorphicFiberStructure = ({
+    children,
+  }: {
+    children: JSX.Element
+  }) => {
+    return (
+      <>
+        <Noop />
+        <AppContainer>
+          <>
+            {dev ? (
+              <>
+                {children}
+                <Noop />
+              </>
+            ) : (
+              children
+            )}
+            <Noop />
+          </>
+        </AppContainer>
+      </>
+    )
+  }
+
   props = await loadGetInitialProps(App, {
     AppTree: ctx.AppTree,
     Component,
@@ -976,13 +1008,13 @@ export async function renderToHTML(
           enhanceComponents(options, App, Component)
 
         const html = ReactDOMServer.renderToString(
-          <AppContainer>
+          <AppContainerWithIsomorphicFiberStructure>
             <EnhancedApp
               Component={EnhancedComponent}
               router={router}
               {...props}
             />
-          </AppContainer>
+          </AppContainerWithIsomorphicFiberStructure>
         )
         return { html, head }
       }
@@ -1015,9 +1047,9 @@ export async function renderToHTML(
         ctx.err && ErrorDebug ? (
           <ErrorDebug error={ctx.err} />
         ) : (
-          <AppContainer>
+          <AppContainerWithIsomorphicFiberStructure>
             <App {...props} Component={Component} router={router} />
-          </AppContainer>
+          </AppContainerWithIsomorphicFiberStructure>
         )
 
       const bodyResult = concurrentFeatures
diff --git a/test/integration/react-18/app/pages/use-id.js b/test/integration/react-18/app/pages/use-id.js
new file mode 100644
index 000000000000000..1b5f6fef28fca0f
--- /dev/null
+++ b/test/integration/react-18/app/pages/use-id.js
@@ -0,0 +1,5 @@
+import { useId } from 'react'
+
+export default function Page() {
+  return <div id="id">{useId()}</div>
+}
diff --git a/test/integration/react-18/test/basics.js b/test/integration/react-18/test/basics.js
index bb3c4ad99ced4f7..d54a9b02e4dd436 100644
--- a/test/integration/react-18/test/basics.js
+++ b/test/integration/react-18/test/basics.js
@@ -28,4 +28,15 @@ export default (context) => {
     expect(content).toBe('rab')
     expect(nextData.dynamicIds).toBeUndefined()
   })
+
+  it('useId() values should match on hydration', async () => {
+    const html = await renderViaHTTP(context.appPort, '/use-id')
+    const $ = cheerio.load(html)
+    const ssrId = $('#id').text()
+
+    const browser = await webdriver(context.appPort, '/use-id')
+    const csrId = await browser.eval('document.getElementById("id").innerText')
+
+    expect(ssrId).toEqual(csrId)
+  })
 }