Add invariant with debug information when failing to load static file

packages/next/server/base-server.ts

@@ -22,6 +22,7 @@ import {
  NormalizeError,
  DecodeError,
  normalizeRepeatedSlashes,
+ MissingStaticPage,
 } from '../shared/lib/utils'
 import type { PreviewData } from 'next/types'
 import type { PagesManifest } from '../build/webpack/plugins/pages-manifest-plugin'
@@ -1856,6 +1857,26 @@ export default abstract class Server<ServerOptions extends Options = Options> {
  }
  } catch (error) {
  const err = getProperError(error)
+
+ if (error instanceof MissingStaticPage) {
+ console.error(
+ 'Invariant: failed to load static page',
+ JSON.stringify(
+ {
+ page,
+ url: ctx.req.url,
+ matchedPath: ctx.req.headers['x-matched-path'],
+ initUrl: getRequestMeta(ctx.req, '__NEXT_INIT_URL'),
+ didRewrite: getRequestMeta(ctx.req, '_nextDidRewrite'),
+ rewroteUrl: getRequestMeta(ctx.req, '_nextRewroteUrl'),
+ },
+ null,
+ 2
+ )
+ )
+ throw err
+ }
+
  if (err instanceof NoFallbackError && bubbleNoFallback) {
  throw err
  }

packages/next/server/require.ts

@@ -11,7 +11,7 @@ import { normalizeLocalePath } from '../shared/lib/i18n/normalize-locale-path'
 import { normalizePagePath } from '../shared/lib/page-path/normalize-page-path'
 import { denormalizePagePath } from '../shared/lib/page-path/denormalize-page-path'
 import type { PagesManifest } from '../build/webpack/plugins/pages-manifest-plugin'
-import { PageNotFoundError } from '../shared/lib/utils'
+import { PageNotFoundError, MissingStaticPage } from '../shared/lib/utils'
 
 export function getPagePath(
  page: string,
@@ -90,7 +90,9 @@ export function requirePage(
  appDirEnabled
  )
  if (pagePath.endsWith('.html')) {
- return promises.readFile(pagePath, 'utf8')
+ return promises.readFile(pagePath, 'utf8').catch((err) => {
+ throw new MissingStaticPage(page, err.message)
+ })
  }
  return require(pagePath)
 }

packages/next/shared/lib/utils.ts

@@ -413,6 +413,13 @@ export class PageNotFoundError extends Error {
  }
 }
 
+export class MissingStaticPage extends Error {
+ constructor(page: string, message: string) {
+ super()
+ this.message = `Failed to load static file for page: ${page} ${message}`
+ }
+}
+
 export class MiddlewareNotFoundError extends Error {
  code: string
  constructor() {

test/production/required-server-files.test.ts

@@ -138,6 +138,24 @@ describe('should set-up next', () => {
  if (server) await killApp(server)
  })
 
+ it('should show invariant when an automatic static page is requested', async () => {
+ const toRename = `standalone/.next/server/pages/auto-static.html`
+ await next.renameFile(toRename, `${toRename}.bak`)
+
+ try {
+ const res = await fetchViaHTTP(appPort, '/auto-static', undefined, {
+ headers: {
+ 'x-matched-path': '/auto-static',
+ },
+ })
+
+ expect(res.status).toBe(500)
+ await check(() => stderr, /Invariant: failed to load static page/)
+ } finally {
+ await next.renameFile(`${toRename}.bak`, toRename)
+ }
+ })
+
  it.each([
  {
  case: 'redirect no revalidate',

test/production/required-server-files/pages/auto-static.js

@@ -0,0 +1,3 @@
+export default function Page() {
+ return <p>automatic static page</p>
+}