neohaskell/docs/archive/2026-07-ai-artifacts/claude-skills/integration-pipeline-preview/11-build-loop/04-hlint

ARCHIVAL KNOWLEDGE — DO NOT USE OR REFERENCE. Superseded by codemap/ + root AGENTS.md. Scheduled for deletion once the pipeline is verified (Phase 6). Manifest: docs/archive/2026-07-ai-artifacts/MANIFEST.md

name: 04-hlint description: Runs hlint on changed files and captures warnings for later surfacing in the PR body. kind: leaf executor: script model: claude-haiku-4-5-20251001

Hlint

Runs hlint on the changed Haskell files and writes the output to .integration-pipeline/hlint.log. Hlint warnings are collected, not gated — this leaf does not fail the build loop on warnings. The PR-body step in phase 16 surfaces the log contents to the PR reviewer.

Inputs

• The list of changed Haskell files from git diff --name-only HEAD -- '*.hs' '*.lhs' (the pathspec keeps an empty match exit-code 0).

Plan

1. Compute the changed Haskell files list → verify: list captured (may be empty).
2. Run hlint on the list, redirecting stdout+stderr to .integration-pipeline/hlint.log → verify: log written.
3. Always exit 0 — the leaf's job is to record the warnings, not to block on them → verify: caller sees exit 0 unless hlint is missing or the working tree is corrupt.

Assumptions:

• The build loop already gates on cabal build all and cabal test. Hlint is style guidance, not correctness, so it does not need to stop the loop.
• The PR-body step (phase 16.1) reads .integration-pipeline/hlint.log and embeds any non-empty contents in the PR description so a human reviewer (or CI's hlint check) sees them.

If any assumption fails, refuse — do not guess.

Steps

1. Compute changed files: git diff --name-only HEAD -- '*.hs' '*.lhs' (pathspec is empty-match safe — no grep pipe).
2. If the list is empty, write an empty .integration-pipeline/hlint.log and exit 0.
3. Otherwise run: nix develop --command hlint <files...> > .integration-pipeline/hlint.log 2>&1 || true — the trailing || true keeps the leaf at exit 0 regardless of how many warnings hlint emitted.
4. If the log is non-empty, print a one-line summary to stdout (hlint produced N warning(s); see .integration-pipeline/hlint.log and the PR body). Do not surface as failure.
5. Exit 0.

Output

.integration-pipeline/hlint.log written (possibly empty). Exit code is always 0 unless a hard environmental failure occurred (hlint missing, not in a git repo).

Refusals

• nix not on PATH → refuse: "nix not found; the repo's dev shell is required for hlint" and exit non-zero. Environment failure, not a style warning.
• Repo not a git working tree → refuse: "not in a git repo" and exit non-zero.