attestantio/.claude/skills/add-rule

Add Rule Skill

This skill helps you add new rules to the attgo-linter project.

Usage

When asked to add a new linter rule, follow these steps:

1. Gather Information

Ask the user for:

• Rule name: e.g., "no-global-vars"
• Description: What the rule checks
• Priority: HIGH (enabled by default), MEDIUM, or LOW (disabled by default)
• Bad example: Code that should trigger the warning
• Good example: Code that passes the check
• Configuration options: Any customizable settings

2. Create Analyzer Package

Create the following files:

analyzers/{rulename}/
├── analyzer.go
└── analyzer_test.go

The analyzer name must use underscores (not hyphens): attgo_{rule_name}

3. Create Test Fixtures

analyzers/{rulename}/testdata/src/{rulename}/
└── {rulename}.go

Use // want \regex pattern`` comments for expected diagnostics.

4. Register in Plugin

Update plugin.go:

• Add import
• Add to BuildAnalyzers() with config check

Update config.go:

• Add Enable{RuleName} field to Config struct
• Set default in DefaultConfig()

Update plugin.go config handling:

• Add explicit check for the setting in New()

5. Update Documentation

• Add rule section to README.md
• Create docs/rules/attgo-{rule-name}.md
• Update CHANGELOG.md

6. Verify

Run tests:

go test ./...

Template: analyzer.go

// Copyright © 2026 Attestant Limited.
// Licensed under the Apache License, Version 2.0 (the "License");
// ...

// Package {rulename} provides an analyzer that {description}.
package {rulename}

import (
    "golang.org/x/tools/go/analysis"
)

const (
    analyzerName = "attgo_{rule_name}"
    doc          = `{short description}

{detailed explanation}

Bad:
    {bad example}

Good:
    {good example}`
)

// Analyzer is the {description} analyzer.
var Analyzer = &analysis.Analyzer{
    Name: analyzerName,
    Doc:  doc,
    Run:  run,
}

func run(pass *analysis.Pass) (any, error) {
    for _, file := range pass.Files {
        // Implementation
    }
    return nil, nil
}

Template: analyzer_test.go

// Copyright © 2025 Attestant Limited.
// ...

package {rulename}_test

import (
    "testing"

    "github.com/attestantio/attgo-linter/analyzers/{rulename}"
    "golang.org/x/tools/go/analysis/analysistest"
)

func TestAnalyzer(t *testing.T) {
    testdata := analysistest.TestData()
    analysistest.Run(t, testdata, {rulename}.Analyzer, "{rulename}")
}

Template: testdata

// Copyright © 2025 Attestant Limited.
// ...

package {rulename}

// Bad case.
var bad = something // want `expected error`

// Good case.
var good = something // No warning

Checklist

• [ ] Created analyzers/{rulename}/analyzer.go
• [ ] Created analyzers/{rulename}/analyzer_test.go
• [ ] Created analyzers/{rulename}/testdata/src/{rulename}/{rulename}.go
• [ ] Added import to plugin.go
• [ ] Added to BuildAnalyzers() in plugin.go
• [ ] Added config field to config.go
• [ ] Added default value in DefaultConfig()
• [ ] Added config handling in New()
• [ ] Tests pass: go test ./...
• [ ] Added documentation to README.md
• [ ] Updated CHANGELOG.md