This repository demonstrates a webpack cache warning that occurs when using Next.js middleware with Sentry configuration.

When running npm run build with both Next.js middleware and Sentry HOC configured, the following warning appears:

<w> [webpack.cache.PackFileCacheStrategy] Serializing big strings (253kiB) impacts deserialization performance (consider using Buffer instead and decode when needed)

1. Install dependencies

   npm install

2. Run the build

   npm run build

3. Observe the warning in console output

• ⚠️ WITH middleware.ts + Sentry HOC → Warning appears
• ✅ WITHOUT middleware.ts + Sentry HOC → No warning
• ✅ WITH middleware.ts + WITHOUT Sentry HOC → No warning

1. The warning is triggered by the combination of Next.js middleware and Sentry's withSentryConfig HOC
2. The content/logic within the middleware doesn't matter - even an empty middleware function triggers it
3. Removing either the middleware file or the Sentry HOC eliminates the warning
4. The warning suggests that large strings (253kiB) are being serialized, impacting webpack cache performance

• Next.js: 15.3.3
• @sentry/nextjs: 9.32.0
• Node.js: Latest LTS
• TypeScript: 5.7.2

The build should complete without webpack cache warnings when using standard Next.js middleware with Sentry instrumentation.