prefer-nextjs-16-minor-performance-milestone

Workflow findings use root dependency version evidence. Unresolved ranges crossing 16.3 are not treated as old installed versions.

What it flags

Flags workflows that visibly run next build when the repository depends on Next.js 16.0, 16.1, or 16.2.

The rule recommends 16.3.x because that is the main 16.x CI/build milestone.

Why it matters

Next.js 16.3 enables Turbopack’s persistent filesystem cache for next build by default. Repeat CI builds can reuse work from previous runs — Vercel reports up to 5.5x faster repeat builds when .next/cache is restored between runs. It also cuts next dev memory use by up to 90% and adds TypeScript 7 type checking.

The 16.1 and 16.2 releases mostly improved the dev server (filesystem cache for next dev, faster next dev startup), not production builds, so 16.3 is the CI-relevant target.

Current heuristic

The rule requires both:

• a detectable next dependency in root package.json
• a workflow job that visibly runs next build

It does not flag Next.js 16.3 or newer, and it does not cover Next.js 15 (which reaches end of life on 2026-10-21).

When to ignore it

Ignore this finding when:

• the project is intentionally pinned below 16.3 for compatibility reasons
• the visible workflow job does not represent a meaningful Next.js production build

Suggested verification

• Compare next build wall-clock time across repeated runs with and without a restored .next/cache
• Confirm a .next/cache cache step exists, otherwise the filesystem cache cannot help (see missing-next-build-cache)

Sources

• https://nextjs.org/blog/next-16
• https://nextjs.org/blog/next-16-1
• https://nextjs.org/blog/next-16-2
• https://nextjs.org/blog/next-16-3-turbopack