Enable Turbopack for production builds

[hellno]

Summary

Turbopack is Next.js's new Rust-based bundler that promises significantly faster builds. However, enabling Turbopack for production builds currently fails due to an incompatibility with @farcaster/hub-web.

Error Details

When running npx next build --turbopack, the build fails with:

./node_modules/@farcaster/hub-web/dist/index.mjs
Module not found: The high bits of the position 4586771 are not all 0s or 1s. modules_header_width=9, module=215

./node_modules/@farcaster/hub-web/dist/index.mjs
Module not found: The high bits of the position 4586771 are not all 0s or 1s. modules_header_width=9, module=215

This error occurs in Turbopack's Rust internals when processing the protobuf-heavy @farcaster/hub-web package.

Context

• Next.js version: 15.5.9
• @farcaster/hub-web version: 0.9.2 (bundled with @farcaster/core)
• Current bundler: webpack (via Sentry wrapper)
• Turbopack status: Works for dev server (next dev --turbo), fails for production builds

Why This Matters

Turbopack could significantly improve build times:

• Current webpack build: ~25-35s
• Expected Turbopack improvement: 2-5x faster for incremental builds
• Better caching and parallelization

Root Cause

The @farcaster/hub-web package uses Protocol Buffers (protobuf) for Farcaster Hub communication. Turbopack's Rust-based module resolution appears to have issues with:

1. Large generated protobuf files
2. Complex module structure in the package's ESM output

Potential Solutions

1. Wait for Turbopack fix: This appears to be a Turbopack beta limitation that may be fixed in future releases
2. Report upstream to Vercel: File issue in Next.js/Turbopack repo with reproduction
3. Use alternative Farcaster package: If available, use a package without protobuf dependency
4. Conditional bundling: Exclude @farcaster/hub-web from Turbopack processing (if supported)

Related Links

• Next.js Turbopack docs
• Turbopack GitHub
• @farcaster/hub-web package

Acceptance Criteria

• Production build succeeds with next build --turbopack
• Build times are measurably improved
• No functionality regression in Farcaster Hub communication