code-like-gopher

When to Use

Use this skill when:

• Writing, reviewing, or refactoring Go code
• Setting up Go project structure and tooling
• Debugging concurrency issues
• Configuring linters and formatters
• Writing idiomatic Go code

Prerequisites Check

Before starting any Go work:

# Check Go version
go version

# Check go.mod version requirement
grep '^go ' go.mod 2>/dev/null | awk '{print $2}'

# Check if golangci-lint is available
command -v golangci-lint

---

Instructions

General Coding Approach

• All naming and comments must be in English
• Always check the Go version in go.mod and use appropriate language features
• Starting with Go 1.22+, the loop variable capture issue is fixed
• Starting with Go 1.23+, range-over-integers is available:

// Go 1.23+ only
for i := range 10 {
    fmt.Println(i)
}

// Go 1.22+ - loop variable capture is safe
for i := range items {
    go func() {
        fmt.Println(i) // safe, no need for tt := tt
    }()
}

---

Formatting and Linting

golangci-lint is the standard tool for Go code quality.

# Install if missing
brew install golangci-lint      # macOS
# or
go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest

Check for existing config files:

• .golangci.yml / .golangci.yaml
• .golangci.toml / .golangci.json

If config version is not "2", migrate:

golangci-lint migrate

Minimal .golangci.yml Config

version: "2"

run:
  timeout: 5m
  tests: false

linters:
  enable:
    - errcheck
    - govet
    - ineffassign
    - staticcheck
    - unused
    - misspell
    - unconvert
    - unparam
    - gosec
    - prealloc
    - revive
    - wrapcheck
  settings:
    govet:
      enable:
        - assign
        - appends
        - bools
        - defers
        - shadow
        - unmarshal
        - waitgroup
        - lostcancel
        - slog
        - unreachable
    errcheck:
      check-type-assertions: true
      exclude-functions:
        - fmt.Fprintln
        - fmt.Fprintf
    wrapcheck:
      ignore-package-globs:
        - encoding/*
        - github.com/pkg/*
    revive:
      enable-all-rules: true
      rules:
        - name: package-comments
          disabled: true
        - name: cognitive-complexity
          disabled: true
        - name: cyclomatic
          disabled: true
        - name: function-length
          disabled: true
        - name: line-length-limit
          arguments: [120]
        - name: add-constant
          arguments:
            - max-lit-count: "3"
              allow-strs: '""'
              allow-ints: "0,1,2,10,64"

formatters:
  enable:
    - gofmt
    - gofumpt
    - goimports
    - golines
  settings:
    golines:
      max-len: 120