Out of the box nextjs pnpm monorepo won't boot: Cannot find module 'next/dist/server/lib/start-server.js'

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https://matestma.netlify.app/

The repro repo is available here: GitHub - makeagent/ma-next

This is a brand new Next 15.3 site using pnpm. I then moved it into a web folder to simulate a basic monorepo. The build succeeds, but loading the page fails with:

May 6, 09:29:33 AM: ERROR Unhandled Promise Rejection {“errorType”:“Runtime.UnhandledPromiseRejection”,“errorMessage”:“Error: Cannot find module ‘next/dist/server/lib/start-server.js’\nRequire stack:\n- /var/task/.netlify/dist/run/next.cjs”,“reason”:{“errorType”:“Error”,“errorMessage”:“Cannot find module ‘next/dist/server/lib/start-server.js’\nRequire stack:\n- /var/task/.netlify/dist/run/next.cjs”,“code”:“MODULE_NOT_FOUND”,“requireStack”:[“/var/task/.netlify/dist/run/next.cjs”],“stack”:[“Error: Cannot find module ‘next/dist/server/lib/start-server.js’”,“Require stack:”,“- /var/task/.netlify/dist/run/next.cjs”," at Function._resolveFilename (node:internal/modules/cjs/loader:1225:15)“,” at Function._load (node:internal/modules/cjs/loader:1055:27)“,” at TracingChannel.traceSync (node:diagnostics_channel:322:14)“,” at wrapModuleLoad (node:internal/modules/cjs/loader:220:24)“,” at Module.require (node:internal/modules/cjs/loader:1311:12)“,” at require (node:internal/modules/helpers:136:16)“,” at Object. (/var/task/.netlify/dist/run/next.cjs:498:30)“,” at Module._compile (node:internal/modules/cjs/loader:1554:14)“,” at Object..js (node:internal/modules/cjs/loader:1706:10)“,” at Module.load (node:internal/modules/cjs/loader:1289:32)“]},“promise”:{},“stack”:[“Runtime.UnhandledPromiseRejection: Error: Cannot find module ‘next/dist/server/lib/start-server.js’”,“Require stack:”,”- /var/task/.netlify/dist/run/next.cjs"," at process. (file:///var/runtime/index.mjs:1276:17)“,” at process.emit (node:events:518:28)“,” at emitUnhandledRejection (node:internal/process/promises:252:13)“,” at throwUnhandledRejectionsMode (node:internal/process/promises:388:19)“,” at processPromiseRejections (node:internal/process/promises:475:17)“,” at process.processTicksAndRejections (node:internal/process/task_queues:106:32)"]}

I’ve tried various different approaches as per the commit history of that repo, but the best outcome is that it builds, and then throws this error on launch…

2

After trying a LOT of options, I gave up and created a new repo and deployed the subtree of my main repo to it using git subtree, and that worked.

Helpful to see that all other variables remaining the same the site can be deployed. It is just the monorepo that causes issues.

3

Did you refer to: Next.js on Netlify - OpenNext?

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I did indeed. try the hoist · makeagent/ma-next@6604307 · GitHub

I also tried the npmrc method. No luck on both accounts.