Turbopack Error: Failed to write app endpoint /(private)/promotions/page

[hakilee]

Turbopack version: v16.0.0-canary.19
Next.js version: 0.0.0

Error message:

Turbopack Error: Failed to write app endpoint /(private)/promotions/page

Panic log:

---------------------------
[project]/apps/admin/src/styles/globals.css [app-client] (css)

Caused by:
- reading file /Users/haklee/Workspace/COCSO/websites/apps/admin/src/app/(popup)/promotions/update-popup
- Is a directory (os error 21)

Debug info:
- Execution of subscribe_issues_and_diags_operation failed
- Execution of <AppEndpoint as Endpoint>::server_changed failed
- Execution of *Project::server_changed failed
- Execution of *AppEndpointOutput::server_assets failed
- Execution of AppEndpoint::output failed
- Execution of AppProject::app_module_graphs failed
- Execution of *<AppEndpoint as Endpoint>::additional_entries failed
- Execution of *ModuleGraph::from_graphs failed
- Execution of SingleModuleGraph::new_with_entries_visited_intern failed
- [project]/apps/admin/src/styles/globals.css [app-client] (css)
- Execution of primary_chunkable_referenced_modules failed
- Execution of <CssModuleAsset as Module>::references failed
- Execution of parse_css failed
- Execution of <PostCssTransformedAsset as Asset>::content failed
- Execution of PostCssTransformedAsset::process failed
- Execution of <DiskFileSystem as FileSystem>::read failed
- reading file /Users/haklee/Workspace/COCSO/websites/apps/admin/src/app/(popup)/promotions/update-popup
- Is a directory (os error 21)
---------------------------
Failed to write app endpoint /(private)/promotions/page

Caused by:
- [project]/apps/admin/src/styles/globals.css [app-client] (css)
- reading file /Users/haklee/Workspace/COCSO/websites/apps/admin/src/app/(popup)/promotions/update-popup
- Is a directory (os error 21)

Debug info:
- Execution of get_written_endpoint_with_issues_operation failed
- Execution of endpoint_write_to_disk failed
- Execution of <AppEndpoint as Endpoint>::output failed
- Failed to write app endpoint /(private)/promotions/page
- Execution of AppEndpoint::output failed
- Execution of AppProject::app_module_graphs failed
- Execution of *<AppEndpoint as Endpoint>::additional_entries failed
- Execution of *ModuleGraph::from_graphs failed
- Execution of SingleModuleGraph::new_with_entries_visited_intern failed
- [project]/apps/admin/src/styles/globals.css [app-client] (css)
- Execution of primary_chunkable_referenced_modules failed
- Execution of <CssModuleAsset as Module>::references failed
- Execution of parse_css failed
- Execution of <PostCssTransformedAsset as Asset>::content failed
- Execution of PostCssTransformedAsset::process failed
- Execution of <DiskFileSystem as FileSystem>::read failed
- reading file /Users/haklee/Workspace/COCSO/websites/apps/admin/src/app/(popup)/promotions/update-popup
- Is a directory (os error 21)

next-panic-31e4528edb58e5bb40bff0ff2a61a1f0.log

[hakilee]

This occurred when navigating to a route in the App Router environment without a page.tsx file present.
I'm using Tailwind CSS v4, and the issue disappeared after restarting Next.js, so it’s currently not reproducible.

[sakib-maho]

This error occurs because Turbopack is trying to read a directory (update-popup) as if it were a file. The key error is: reading file /Users/haklee/Workspace/COCSO/websites/apps/admin/src/app/(popup)/promotions/update-popup - Is a directory (os error 21)

Solution 1: Check Your File Structure

Make sure you have the correct file structure in your (popup)/promotions/ directory:

src/app/(popup)/promotions/
├── page.tsx (or page.js)
├── update-popup/
│ └── page.tsx (or page.js)
└── layout.tsx (if needed)

Solution 2: Fix the Directory Issue

The error suggests that update-popup is a directory but Turbopack expects a file. You need to either:

Option A: Create a page file inside the directory

# Create the missing page file
touch src/app/(popup)/promotions/update-popup/page.tsx

Option B: Rename the directory if it's not meant to be a route

# Rename to avoid route conflict
mv src/app/(popup)/promotions/update-popup src/app/(popup)/promotions/update-popup-component

Solution 3: Clear Cache and Rebuild

rm -rf .next
rm -rf .turbo
npm run dev

Solution 4: Check for Conflicting Routes

Make sure you don't have conflicting route structures. The error mentions both /(private)/promotions/page and /(popup)/promotions/update-popup - ensure these don't conflict.

Solution 5: Use Webpack Temporarily

If the issue persists, run with webpack instead of Turbopack:

npm run dev -- --no-turbo

The main issue is the file system structure - Turbopack expects files but found a directory. Fix the file structure first, then clear the cache. Let me know if you need help with the specific file structure!

[nextjs-bot]

2 duplicate discussions were consolidated into this one:

• Turbopack Error: Failed to write app endpoint /page #88284 (1 upvote, 1 comment)
• Turbopack Error: [project]/src/app/globals.css [app-client] (css) #88361 (1 upvote, 1 comment)

Combined engagement from duplicates: 2 upvotes, 2 comments

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This comment was added automatically by discussion consolidation tool.

[nextjs-bot]

This discussion appears to be a duplicate of #88553.

Please follow the discussion there: #88553

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This comment was added automatically by discussion consolidation tool. If you believe this is in error, feel free to re-open the discussion.