Errors not clear Next 16 Build with Turbopack

[JacobWeisenburger]

after upgrading to next 16, I wanted to start using turbopack. However, it seems that when I run next build then I get a bunch of errors in my terminal but none of it seems to tell me what is wrong or how to fix it. I have tried googling a lot of the terminal outputs with no luck. Can someone please help me understand what I'm doing wrong?

Below I have included the terminal output.

$ next build
   ▲ Next.js 16.0.3 (Turbopack)
   - Environments: .env.local

   Creating an optimized production build ...

> Build error occurred
Error: Turbopack build failed with 5 errors:
./node_modules/@weis-guys/result/index.js
Code generation for chunk item errored
An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-rsc] (ecmascript)

Caused by:
- got 8 segments, expected 4 or 5

Debug info:
- An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-rsc] (ecmascript)
- Execution of <MergedEcmascriptModuleChunkItem as EcmascriptChunkItem>::content_with_async_module_info failed
- Execution of *EcmascriptChunkItemContent::new failed
- Execution of EcmascriptModuleContent::new_merged failed
- got 8 segments, expected 4 or 5

Import traces:
  Server Component:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/serverActions/NewInventoryAlert/server.ts

  App Route:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/LoanApp_server.ts
    ./src/app/api/loan-app/route.ts

  Client Component Browser:
    ./node_modules/@weis-guys/result/index.js [Client Component Browser]
    ./src/constants/schema/Car_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]

  Client Component SSR:
    ./node_modules/@weis-guys/result/index.js [Client Component SSR]
    ./src/constants/schema/Car_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]


./node_modules/@weis-guys/result/index.js
Code generation for chunk item errored
An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-ssr] (ecmascript)

Caused by:
- got 8 segments, expected 4 or 5

Debug info:
- An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-ssr] (ecmascript)
- Execution of <ModuleChunkItem as EcmascriptChunkItem>::content_with_async_module_info failed
- Execution of *EcmascriptChunkItemContent::new failed
- Execution of EcmascriptModuleContent::new failed
- got 8 segments, expected 4 or 5

Import traces:
  Server Component:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/serverActions/NewInventoryAlert/server.ts

  App Route:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/LoanApp_server.ts
    ./src/app/api/loan-app/route.ts

  Client Component Browser:
    ./node_modules/@weis-guys/result/index.js [Client Component Browser]
    ./src/constants/schema/Car_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]

  Client Component SSR:
    ./node_modules/@weis-guys/result/index.js [Client Component SSR]
    ./src/constants/schema/Car_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]

---

This seems to be an unrelated issue, but I still don't know what it's asking me to do.

./node_modules/next/dist/esm/build/templates/app-route.js
Code generation for chunk item errored
An error occurred while generating the chunk item [project]/node_modules/next/dist/esm/build/templates/app-route.js { INNER_APP_ROUTE => "[project]/src/app/api/loan-app/route.ts [app-route] (ecmascript)" } [app-route] (ecmascript)

Caused by:
- got 8 segments, expected 4 or 5

Debug info:
- An error occurred while generating the chunk item [project]/node_modules/next/dist/esm/build/templates/app-route.js { INNER_APP_ROUTE => "[project]/src/app/api/loan-app/route.ts [app-route] (ecmascript)" } [app-route] (ecmascript)
- Execution of <MergedEcmascriptModuleChunkItem as EcmascriptChunkItem>::content_with_async_module_info failed
- Execution of *EcmascriptChunkItemContent::new failed
- Execution of EcmascriptModuleContent::new_merged failed
- got 8 segments, expected 4 or 5

[icyJoseph]

Any chance we could see a repository? Feels like somehow there's some server -> client -> server module imports. I guess Webpack says nothing? Maybe it just silently fails?

[JacobWeisenburger]

https://github.com/JacobWeisenburger/unclear-errors

[icyJoseph]

Ah I think the problem is that your v1 of @weis-guys/result uses "type": "module", - totally unclear error yes

[JacobWeisenburger]

@weis-guys/result v2.0.1 uses "type": "module" also, so I'm not sure what you are suggesting.

[icyJoseph]

🤔 odd - I have a project with @weis-guys/result that builds without issue, but it uses v2 - in the link you shared v1 is used. I made the mistake of just looking at that v1 package.json - my bad.

I wonder if the problem is the * export pattern then. I think I've seen a PR or issue about this recently.

[JacobWeisenburger]

can you tell me which file in @weis-guys/result uses * export pattern? Because I'm not seeing that.

[JacobWeisenburger]

The only thing I can see that might be contributing to this is that @weis-guys/[email protected] & freerstore are minified, but @weis-guys/[email protected] is not

[icyJoseph]

Could you fact check me here, since I've been getting this one wrong so many times. If you go to node_modules/@weis-guys/result/index.js in your repro repo, and delete the debugId and sourceMap, then it builds right?

[JacobWeisenburger]

that seemed to help with this issue. But I have a new issue that could be related.

$ yarn build
yarn run v1.22.19
$ next build
   ▲ Next.js 16.0.3 (Turbopack)
   - Environments: .env.local

   Creating an optimized production build ...
 ✓ Compiled successfully in 4.7s
 ✓ Finished TypeScript in 6.5s
   Collecting page data using 23 workers  ..Error: Failed to load chunk server/chunks/[root-of-the-server]__9fa1e44d._.js from runtime for chunk server/app/api/loan-app/route.js
    at loadRuntimeChunkPath (C:\Software\royal-drive-dms2\.next\server\chunks\[turbopack]_runtime.js:636:15)
    at loadRuntimeChunk (C:\Software\royal-drive-dms2\.next\server\chunks\[turbopack]_runtime.js:605:9)
    at Object.c (C:\Software\royal-drive-dms2\.next\server\chunks\[turbopack]_runtime.js:766:25)
    at Object.<anonymous> (C:\Software\royal-drive-dms2\.next\server\app\api\loan-app\route.js:5:3) {
  [cause]: SyntaxError: Identifier 'O' has already been declared
      at <unknown> (C:\Software\royal-drive-dms2\.next\server\chunks\[root-of-the-server]__9fa1e44d._.js:48)
}

> Build error occurred
Error: Failed to collect page data for /api/loan-app
    at ignore-listed frames {
  type: 'Error'
}
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

// api\loan-app\route.ts
import 'server-only'
import { LoanApp_server } from '../../../lib/LoanApp_server'

export async function GET ( request: Request ) {
    const url = new URL( request.url )
    const id = url.searchParams.get( 'id' )
    if ( !id ) {
        const message = `Missing Loan Id`
        console.error( message )
        return new Response( message, { status: 400 } )
    }

    const publicData = await LoanApp_server.getPublicData( id )
    if ( !publicData.success ) {
        console.error( publicData.error )
        return Response.json( publicData.error, { status: publicData.error.status } )
    }

    return Response.json( publicData.value )
}