Also provide AppTree in NextPageContext

packages/next-server/lib/router/router.ts

@@ -416,8 +416,12 @@ export default class Router implements BaseRouter {
         }
 
         return new Promise((resolve, reject) => {
-          const ctx = { pathname, query, asPath: as }
-          this.getInitialProps(Component, ctx).then(props => {
+          // we provide AppTree later so this needs to be `any`
+          this.getInitialProps(Component, {
+            pathname,
+            query,
+            asPath: as,
+          } as any).then(props => {
             routeInfo.props = props
             this.components[route] = routeInfo
             resolve(routeInfo)
@@ -450,9 +454,12 @@ export default class Router implements BaseRouter {
           resolve(
             this.fetchComponent('/_error').then(Component => {
               const routeInfo: RouteInfo = { Component, err }
-              const ctx = { err, pathname, query }
               return new Promise(resolve => {
-                this.getInitialProps(Component, ctx).then(
+                this.getInitialProps(Component, {
+                  err,
+                  pathname,
+                  query,
+                } as any).then(
                   props => {
                     routeInfo.props = props
                     routeInfo.error = err
@@ -635,8 +642,10 @@ export default class Router implements BaseRouter {
           return { error: err.message, status }
         })
     } else {
+      const AppTree = this._wrapApp(App)
+      ctx.AppTree = AppTree
       props = await loadGetInitialProps<AppContextType<Router>>(App, {
-        AppTree: this._wrapApp(App),
+        AppTree,
         Component,
         router: this,
         ctx,

packages/next-server/lib/utils.ts

@@ -96,6 +96,10 @@ export interface NextPageContext {
    * `String` of the actual path including query.
    */
   asPath?: string
+  /**
+   * `Component` the tree of the App to use if needing to render separately
+   */
+  AppTree: NextComponentType
 }
 
 export type AppContextType<R extends NextRouter = NextRouter> = {

packages/next-server/server/render.tsx

@@ -303,19 +303,26 @@ export async function renderToHTML(
 
   // @ts-ignore url will always be set
   const asPath: string = req.url
+  const router = new ServerRouter(pathname, query, asPath)
   const ctx = {
     err,
     req: isStaticPage ? undefined : req,
     res: isStaticPage ? undefined : res,
     pathname,
     query,
     asPath,
+    AppTree: (props: any) => {
+      return (
+        <AppContainer>
+          <App {...props} Component={Component} router={router} />
+        </AppContainer>
+      )
+    },
   }
+  let props: any
   const isDataPrerender =
     pageConfig.experimentalPrerender === true &&
     req.headers['content-type'] === 'application/json'
-  const router = new ServerRouter(pathname, query, asPath)
-  let props: any
 
   if (documentMiddlewareEnabled && typeof DocumentMiddleware === 'function') {
     await DocumentMiddleware(ctx)

packages/next/client/index.js

@@ -218,11 +218,12 @@ export async function renderError (props) {
   // In production we do a normal render with the `ErrorComponent` as component.
   // If we've gotten here upon initial render, we can use the props from the server.
   // Otherwise, we need to call `getInitialProps` on `App` before mounting.
+  const AppTree = wrapApp(App)
   const appCtx = {
-    AppTree: wrapApp(App),
     Component: ErrorComponent,
+    AppTree,
     router,
-    ctx: { err, pathname: page, query, asPath }
+    ctx: { err, pathname: page, query, asPath, AppTree }
   }
 
   const initProps = props.props
@@ -326,11 +327,12 @@ async function doRender ({ App, Component, props, err }) {
     lastAppProps.Component === ErrorComponent
   ) {
     const { pathname, query, asPath } = router
+    const AppTree = wrapApp(App)
     const appCtx = {
       router,
-      AppTree: wrapApp(App),
+      AppTree,
       Component: ErrorComponent,
-      ctx: { err, pathname, query, asPath }
+      ctx: { err, pathname, query, asPath, AppTree }
     }
     props = await loadGetInitialProps(App, appCtx)
   }

test/integration/app-tree/pages/_app.js

@@ -39,7 +39,7 @@ class MyApp extends App {
     const { Component, pageProps, html, router } = this.props
     const href = router.pathname === '/' ? '/another' : '/'
 
-    return html ? (
+    return html && router.pathname !== '/hello' ? (
       <>
         <div dangerouslySetInnerHTML={{ __html: html }} />
         <Link href={href}>
@@ -48,7 +48,7 @@ class MyApp extends App {
       </>
     ) : (
       <Container>
-        <Component {...pageProps} {...{ html }} />
+        <Component {...pageProps} />
       </Container>
     )
   }

test/integration/app-tree/pages/hello.js

@@ -0,0 +1,33 @@
+import { render } from 'react-dom'
+import { renderToString } from 'react-dom/server'
+
+const Page = ({ html }) =>
+  html ? (
+    <>
+      <p>saved:</p>
+      <div dangerouslySetInnerHTML={{ __html: html }} />
+    </>
+  ) : (
+    <p>Hello world</p>
+  )
+
+Page.getInitialProps = async ({ AppTree, pathname, query, asPath }) => {
+  let html
+  const toRender = (
+    <AppTree router={{ pathname, query, asPath }} Component={Page} />
+  )
+
+  if (typeof window !== 'undefined') {
+    const el = document.createElement('div')
+    document.querySelector('body').appendChild(el)
+    render(toRender, el)
+    html = el.innerHTML
+    el.remove()
+  } else {
+    html = renderToString(toRender)
+  }
+
+  return { html }
+}
+
+export default Page

test/integration/app-tree/test/index.test.js

@@ -45,6 +45,11 @@ const runTests = () => {
     html = await browser.eval(`document.documentElement.innerHTML`)
     expect(html).toMatch(/page:.*?\/another/)
   })
+
+  it('should pass AppTree to NextPageContext', async () => {
+    const html = await renderViaHTTP(appPort, '/hello')
+    expect(html).toMatch(/saved:.*?Hello world/)
+  })
 }
 
 describe('Auto Export', () => {