intermittent: Cannot find module for page

Bug report

Describe the bug

While running in dev mode (npm run dev), I get ‘{ Error: Cannot find module for page: /lessons/[album]/[slug]’. This happens occasionaly and I can’t reproduce it on demand.

Once it happens, the Error page will be displayed and then after a few seconds the page will be re-displayed without the error – rendered as it should be.

My page set up:

pages ->
   lessons ->
      [album] ->
         [slug].tsx

The page [slug].tsx indeeds exports all the necessary paths via getStaticPaths (e.g. [ .. {"params":{"album":"mlu","slug":"association-rules"}} .. ])

To Reproduce

I am unable to find a reliable way to demonstrate this on demand.

Expected behavior

Screenshots

If applicable, add screenshots to help explain your problem.

System information

• OS: mac/10.15.6
• Version of Next.js: 9.5 (although I noticed this happening since 9.3)
• Version of Node.js: 10.16.3

[alexkreidler]

For me, I had the yarn dev (next) command running in another terminal. Once I killed that process and ran yarn build && yarn export, the issue went away.

[nick-myers-dt]

I ran into this error today using next build:

info  - Creating an optimized production build  
info  - Compiled successfully

> Build error occurred
Error: Cannot find module for page: /accounts/create/[companyId]
    at pageNotFoundError (/Users/nickmyers/repos/rebuild/admin/node_modules/next/dist/next-server/server/require.js:1:384)
    at getPagePath (/Users/nickmyers/repos/rebuild/admin/node_modules/next/dist/next-server/server/require.js:1:917)
    at /Users/nickmyers/repos/rebuild/admin/node_modules/next/dist/build/index.js:15:3168
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at async Promise.all (index 3)
    at async build (/Users/nickmyers/repos/rebuild/admin/node_modules/next/dist/build/index.js:15:2729) {
  code: 'ENOENT'
}

I ran next build again and it completed without issue.