next.config.ts

import type { NextConfig } from 'next';

// Next 16's cacheComponents (Partial Prerendering) currently trips a dev-only
// upstream bug — `InvariantError: Expected workUnitAsyncStorage to have a store`
// — that throws below the root <Suspense> on `next dev`, so the root
// <ErrorBoundary> replaces the whole app shell with "Something went wrong"
// (even /sign-in, blocking local sign-in entirely). Production builds prerender
// fine, so we keep PPR ON for `next build` / `next start` / CI and disable it
// only for `next dev` to keep the local app usable. Set
// ENABLE_CACHE_COMPONENTS=1 to opt back in locally when you specifically need to
// exercise PPR semantics. Remove this gate once a Next release fixes the dev
// invariant (tracked: vercel/next.js workUnitAsyncStorage dev regression).
const enableCacheComponents = process.env.NODE_ENV === 'production' || process.env.ENABLE_CACHE_COMPONENTS === '1';

const nextConfig: NextConfig = {
  output: 'standalone',
  distDir: process.env.NEXT_DIST_DIR ?? '.next',
  turbopack: {
    root: process.cwd(),
  },
  reactStrictMode: true,
  devIndicators: false,
  compiler: {
    styledComponents: true,
  },
  images: {
    remotePatterns: [
      {
        protocol: 'https',
        hostname: 'avatars.githubusercontent.com',
        pathname: '/**',
      },
    ],
  },
  // Optimize production bundle
  productionBrowserSourceMaps: false,
  // React Compiler auto-memoises components, removing the need for most
  // manual useMemo / useCallback / React.memo wrappers.
  reactCompiler: true,
  // Enable experimental optimizations
  experimental: {
    // Optimize package imports - reduces bundle size by tree-shaking
    optimizePackageImports: ['@primer/react', '@primer/octicons-react', 'react-markdown', 'react-syntax-highlighter'],
  },
  // Next 16 dynamic-IO model: every server fetch must be either explicitly
  // uncached (no-store) or tagged for revalidation. Enforced by
  // scripts/check-server-fetch-tenancy.mjs at CI time. Disabled in `next dev`
  // only — see the enableCacheComponents note above.
  cacheComponents: enableCacheComponents,
  // Keep `@github/copilot-sdk` as a server-only external. The package uses
  // `import.meta.resolve` internally which Turbopack cannot handle, and we
  // never want it bundled into the web image — runtime fail-loud net: if
  // a future code path slips a `require('@github/copilot-sdk')` through
  // every static gate (`scripts/check-copilot-sdk-boundary.mjs`,
  // `scripts/check-web-image-copilot-free.mjs`), startup will crash with
  // "Cannot find module" instead of silently double-executing SDK logic
  // in the web container.
  serverExternalPackages: ['@github/copilot-sdk'],
};

export default nextConfig;