Enum Linter

A Go static analysis tool that ensures only valid enum values are returned for enum types.

Examples

Valid Enum Usage ✅

type StatusEnum string

const (
    StatusActive   StatusEnum = "active"
    StatusInactive StatusEnum = "inactive"
)

func getStatus() StatusEnum {
    return StatusActive  // ✅ Valid - returns enum constant
}

var validStatus StatusEnum = StatusActive  // ✅ Valid - variable assigned enum constant

Invalid Enum Usage ❌

type StatusEnum string

const (
    StatusActive   StatusEnum = "active"
    StatusInactive StatusEnum = "inactive"
)

func getStatus() StatusEnum {
    return "invalid"  // ❌ Error - returns string literal
}

var invalidStatus StatusEnum = "random string"  // ❌ Error - variable assigned string literal

Features

• Enum Detection: Automatically identifies types that have constants defined for them
• Multi-type Support: Works with string, int, float, bool, and iota-based enums
• Return Validation: Ensures only valid enum constants are returned from functions
• Variable Declaration Validation: Ensures only valid enum constants are assigned to variables
• Comprehensive Testing: Full test suite using Go's native testing framework

Installation

# Clone the repository
git clone <repository-url>
cd go_linter

# Build the linter
go build -o enumlinter cmd/main.go

Usage

Command Line

# Analyze a single file
./enumlinter path/to/file.go

# Analyze multiple files
./enumlinter file1.go file2.go

# Analyze a directory
./enumlinter ./path/to/directory

Testing

Run All Tests

./run_tests.sh

Run Tests Manually

# Run analyzer tests
cd pkg/analyzer && go test -v

# Run specific test
go test -v -run TestEnumLinter

Supported Enum Types

• String-based: type Status string
• Int-based: type Priority int
• Float-based: type Score float64
• Bool-based: type Flag bool
• Iota-based: type Color int with iota

Development

Adding New Test Cases

1. Add test files to testdata/
2. Use // want "expected error message" comments for invalid cases
3. Run tests with go test -v

Extending the Linter

The core logic is in pkg/analyzer/analyzer.go. The analyzer:

1. Detects enum types by finding types with constants
2. Validates return statements against enum constants
3. Validates variable declarations against enum constants
4. Reports violations with clear error messages

License

MIT License