golangci_lint_action_go 0.5.0

golangci-lint-action, but reimplemented in Go

golangci-lint-action-go

A Go reimplementation of the golangci-lint GitHub Action. Drop-in replacement that ships as a single self-contained binary — no Node.js runtime required.

Quick start

# .github/workflows/lint.yml
name: Lint

on:
  push:
    branches: [main]
  pull_request:

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-go@v5
        with:
          go-version-file: go.mod

      - uses: StevenACoffman/golangci-lint-action-go@v1

Why a Go reimplementation?

The upstream action is a Node.js composite action. This version replaces the JS runtime with a compiled Go binary:

• No Node.js on the runner — one fewer tool in the dependency chain
• Faster startup — no module resolution or JIT warmup
• Auditable — the same go build / go test workflow as the rest of your project
• Behaviorally identical — same inputs, same cache key format, same exit codes

Common patterns

Pin to a specific version

- uses: StevenACoffman/golangci-lint-action-go@v1
  with:
    version: v2.3.4
    args: --timeout=5m

Version can be v2.3 (maps to the latest v2.3.x patch), v2.3.4 (exact), latest, or empty (auto-detected from go.mod or a version file — see Version resolution).

Lint only new issues on pull requests

- uses: StevenACoffman/golangci-lint-action-go@v1
  with:
    only-new-issues: true

On pull_request and push events the action fetches the diff from the GitHub API and passes --new-from-patch to golangci-lint so only issues touching changed lines are reported. On merge_group events it uses --new-from-rev instead (no network call needed).

Add inline PR annotations

- uses: StevenACoffman/golangci-lint-action-go@v1
  with:
    problem-matchers: true

Registers a problem matcher that parses golangci-lint output and creates inline code annotations directly on the pull request diff.

Monorepo — lint every Go module independently

- uses: StevenACoffman/golangci-lint-action-go@v1
  with:
    experimental: automatic-module-directories

Globs for **/go.mod (excluding vendor/, node_modules/, .git/, dist/) and runs golangci-lint once per discovered module directory.

Use golangci-lint already installed in the runner image

- uses: StevenACoffman/golangci-lint-action-go@v1
  with:
    install-mode: none

Skips download and version resolution; uses whatever golangci-lint is already in PATH.

Install only, then run with custom flags

- uses: StevenACoffman/golangci-lint-action-go@v1
  with:
    install-only: true

- name: Lint
  run: golangci-lint run --fix --out-format=github-actions

Build from source with go install

- uses: StevenACoffman/golangci-lint-action-go@v1
  with:
    install-mode: goinstall
    version: latest

Requires CGO (CGO_ENABLED=1) on the runner; useful when you need a custom build tag or are targeting a platform without a pre-built release binary.

Inputs

Input	Default	Description
version	""	golangci-lint version: v2.3, v2.3.4, latest, or empty for auto-detect
version-file	""	Path to .golangci-lint-version or .tool-versions; ignored when version is set
install-mode	binary	binary — download release archive; goinstall — build with go install; none — expect it in PATH
install-only	false	Install the binary, then exit without running the linter
working-directory	""	Directory to run the linter in; empty means the process working directory
github-token	${{ github.token }}	Token used to fetch PR/push diffs when only-new-issues: true
verify	true	Run golangci-lint config verify before linting
only-new-issues	false	Restrict lint output to issues introduced in the current diff
args	""	Extra flags passed verbatim to golangci-lint run
skip-cache	false	Disable both cache restore and save
skip-save-cache	false	Disable cache save only; restore still runs
cache-invalidation-interval	7	Rotate the cache key every N days; 0 or negative gives a unique key per run
problem-matchers	false	Register the built-in problem matcher for inline PR annotations
debug	""	Comma-separated: cache (print cache status), clean (purge cache before linting)
experimental	""	Comma-separated: automatic-module-directories (lint each go.mod in the repo)

Version resolution

The version to install is determined by the first non-empty source in this order:

1. version input — used verbatim; minor-only versions (e.g. v2.3) are mapped to the latest patch via the upstream version mapping JSON.
2. go.mod — scans for a require github.com/golangci/golangci-lint/v2 vX.Y.Z directive.
3. version-file — reads .golangci-lint-version (raw version string) or .tool-versions (looks for a golangci-lint X.Y.Z line).
4. Latest — fetches the current latest from the upstream version mapping.

Minimum supported version is v2.1. Only the v2 major line is supported.

Caching

The action caches ~/.cache/golangci-lint (Windows: %USERPROFILE%\.cache\golangci-lint) between runs using the GitHub Actions cache API.

Cache key format:

golangci-lint.cache-{RUNNER_OS}-{working-directory}-{interval-bucket}-{go.mod-sha1}

The interval bucket advances every cache-invalidation-interval days (default: 7). This means the cache is shared across all runs within the same week while still rotating regularly to pick up updated lint rules. A second restore key — the same string without the SHA-1 suffix — allows partial hits when only go.mod has changed.

Set skip-cache: true to disable caching entirely, or skip-save-cache: true to restore but never write back (useful when you want to build the cache only from the default branch).

Migrating from golangci-lint-action

All input names are identical. Replace:

- uses: golangci/golangci-lint-action@v6

with:

- uses: StevenACoffman/golangci-lint-action-go@v1

No other changes needed. If you previously passed cache: false (a flag unique to the upstream action), use skip-cache: true here.

Development

# Build
go build -o golangci-lint-action-go ./...

# Test
go test ./...

# Lint
golangci-lint run ./...

See go.mod for the minimum required Go version.

Running the subcommands locally

# Phase 1 — restore cache, install, lint
INPUT_VERSION=v2.3.4 \
INPUT_ARGS="--timeout=5m" \
GITHUB_STATE=/tmp/gh-state \
GITHUB_PATH=/tmp/gh-path \
golangci-lint-action-go run

# Phase 2 — save cache (reads state written by phase 1)
STATE_CACHE_KEY=... \
GITHUB_STATE=/tmp/gh-state \
golangci-lint-action-go post-run

# Other
golangci-lint-action-go version
golangci-lint-action-go --help

Architecture

All business logic lives in internal/ as pure, testable functions. The cmd/ layer is a thin shell that wires them together in the order the spec requires — no logic of its own.

cmd/
  run/
    run.go       – subcommand registration and exec entry point
    cache.go     – cache restore (keys, GOLANGCI_LINT_CACHE, state)
    install.go   – binary install: binary / goinstall / none; plugin builder
    lint.go      – arg assembly, config verify, run, exit-code mapping
  postrun/
    postrun.go   – cache save (reads state written by run phase)

internal/
  gha/           – GitHub Actions protocol: workflow commands, env files, state
  lintver/       – version string parsing, go.mod scan, version-file, mapping fetch
  install/       – platform strings, asset URLs, archive helpers, ParseGoInstallBinPath
  actionscache/  – GitHub Actions Cache REST API client
  cache/         – cache key construction; RestoreCache / SaveCache orchestration
  patch/         – PR/push diff fetch; path-prefix rewriting for working-directory
  plugins/       – .custom-gcl.{yml,yaml,json} detection and custom-binary build
  lint/          – ParseUserArgs, OnlyNewIssuesArgs, PathModeArg, InterpretExitCode

License

See LICENSE.