Ensure directory before flushing cache file

packages/next/next-server/server/spr-cache.ts

@@ -5,7 +5,9 @@ import { promisify } from 'util'
 import { PrerenderManifest } from '../../build'
 import { PRERENDER_MANIFEST } from '../lib/constants'
 import { normalizePagePath } from './normalize-page-path'
+import mkdirpOrig from 'mkdirp'
 
+const mkdirp = promisify(mkdirpOrig)
 const readFile = promisify(fs.readFile)
 const writeFile = promisify(fs.writeFile)
 
@@ -166,7 +168,9 @@ export async function setSprCache(
   // `next build` output's manifest.
   if (sprOptions.flushToDisk) {
     try {
-      await writeFile(getSeedPath(pathname, 'html'), data.html, 'utf8')
+      const seedPath = getSeedPath(pathname, 'html')
+      await mkdirp(path.dirname(seedPath))
+      await writeFile(seedPath, data.html, 'utf8')
       await writeFile(
         getSeedPath(pathname, 'json'),
         JSON.stringify(data.pageData),

test/integration/prerender/pages/user/[user]/profile.js

@@ -0,0 +1,30 @@
+import React from 'react'
+import Link from 'next/link'
+
+// eslint-disable-next-line camelcase
+export async function unstable_getStaticParams () {
+  return []
+}
+
+// eslint-disable-next-line camelcase
+export async function unstable_getStaticProps ({ params }) {
+  return {
+    props: {
+      user: params.user,
+      time: (await import('perf_hooks')).performance.now()
+    },
+    revalidate: 10
+  }
+}
+
+export default ({ user, time }) => {
+  return (
+    <>
+      <p>User: {user}</p>
+      <span>time: {time}</span>
+      <Link href='/'>
+        <a id='home'>to home</a>
+      </Link>
+    </>
+  )
+}

test/integration/prerender/test/index.test.js

@@ -25,6 +25,7 @@ let appPort
 let buildId
 let distPagesDir
 let exportDir
+let stderr
 
 const startServer = async (optEnv = {}) => {
   const scriptPath = join(appDir, 'server.js')
@@ -264,6 +265,11 @@ const runTests = (dev = false) => {
           dataRoute: `/_next/data/${buildId}/blog/[post]/[comment].json`,
           dataRouteRegex: `^\\/_next\\/data\\/${escapedBuildId}\\/blog\\/([^\\/]+?)\\/([^\\/]+?)\\.json$`,
           routeRegex: '^\\/blog\\/([^\\/]+?)\\/([^\\/]+?)(?:\\/)?$'
+        },
+        '/user/[user]/profile': {
+          dataRoute: `/_next/data/${buildId}/user/[user]/profile.json`,
+          dataRouteRegex: `^\\/_next\\/data\\/${escapedBuildId}\\/user\\/([^\\/]+?)\\/profile\\.json$`,
+          routeRegex: `^\\/user\\/([^\\/]+?)\\/profile(?:\\/)?$`
         }
       })
     })
@@ -351,6 +357,12 @@ const runTests = (dev = false) => {
       const val = await browser.eval('window.thisShouldStay')
       expect(val).toBe(true)
     })
+
+    it('should not error when flushing cache files', async () => {
+      await fetchViaHTTP(appPort, '/user/user-1/profile')
+      await waitFor(500)
+      expect(stderr).not.toMatch(/Failed to update prerender files for/)
+    })
   }
 }
 
@@ -374,8 +386,13 @@ describe('SPR Prerender', () => {
         'utf8'
       )
       await nextBuild(appDir)
+      stderr = ''
       appPort = await findPort()
-      app = nextStart(appDir, appPort)
+      app = nextStart(appDir, appPort, {
+        onStderr: msg => {
+          stderr += msg
+        }
+      })
       distPagesDir = join(appDir, '.next/serverless/pages')
       buildId = await fs.readFile(join(appDir, '.next/BUILD_ID'), 'utf8')
     })
@@ -404,8 +421,13 @@ describe('SPR Prerender', () => {
         await fs.unlink(nextConfig)
       } catch (_) {}
       await nextBuild(appDir)
+      stderr = ''
       appPort = await findPort()
-      app = await nextStart(appDir, appPort)
+      app = await nextStart(appDir, appPort, {
+        onStderr: msg => {
+          stderr += msg
+        }
+      })
       buildId = await fs.readFile(join(appDir, '.next/BUILD_ID'), 'utf8')
       distPagesDir = join(appDir, '.next/server/static', buildId, 'pages')
     })