prefer-setup-bun-for-lightweight-node-tooling

What it flags

Flags jobs that:

use actions/setup-node
do not already use oven-sh/setup-bun
do not already use pnpm/action-setup
look like lightweight Node-based tooling jobs
are not visibly using bun or pnpm already

This rule is intended for repository tooling such as lint, formatting, markdown/docs checks, spell checks, and similar non-product tasks.

Why it matters

For lightweight tooling-only jobs, Bun can often reduce setup and command startup overhead compared with a plain setup-node plus npm or yarn path.

Current heuristic

The rule looks for:

visible lightweight tooling commands such as eslint, prettier, oxlint, oxfmt, biome, markdownlint, cspell, actionlint, shellcheck, or yamllint
no visible product-facing or heavier Node work such as test, build, typecheck, bundle, or release commands

The rule intentionally skips:

jobs already using setup-bun
jobs already using pnpm/action-setup
jobs visibly using bun or pnpm
jobs that orchestrate work through nx

When to ignore it

Ignore this finding when:

the job needs npm or yarn specific behavior
the job also does heavier work that the heuristic cannot see
the job installs a monorepo workspace and runs that work through nx
the repository standard intentionally keeps all Node-based jobs on the same runtime setup

Suggested verification