tlin: Lint for gno

Advance Linter for go-like grammar languages.

Introduction

tlin is an linter designed for both Go and gno programming languages. It leverages the functionality of golangci-lint as its main linting engine, providing powerful code analysis for go-like grammar languages.

Inspired by Rust's clippy, tlin aims to provide additional code improvement suggestions beyond the default golangci-lint rules.

Features

• Support for Go (.go) and Gno (.gno) files
• Ability to add custom lint rules
• Additional code improvement suggestion, such as detecting unnecessary code
• Auto-fixing for some lint rules
• Cyclomatic complexity analysis

Installation

• Requirements:
  • Go: 1.22 or higher
  • latest version of gno
  • GNU Make 3.81 or higher (for building)

To install tlin CLI, follow these steps:

1. Clone the repository

git clone https://github.com/gnoswap-labs/tlin

2. Move to the cloned directory

cd tlin

3. Install the CLI

go install ./cmd/tlin

that's it! You can now use the tlin command in your terminal.

Usage

tlin <path>

Replace <path> with the file or directory path you want to analyze.

To check the current directory, run:

tlin .

Adding Custom Lint Rules

tlin allows addition of custom lint rules beyond the default golangci-lint rules. To add a new lint rule, follow these steps:

⚠️ Must update relevant tests if you have added a new rule or formatter.

1. Implement the LintRule interface for your new rule:

type NewRule struct{}

func (r *NewRule) Check(filename string, node *ast.File) ([]types.Issue, error) {
    // Implement your lint rule logic here
    // return a slice of Issues and any error encountered
}

2. Register your new rule in the registerDefaultRules method of the Engine struct in internal/engine.go:

func (e *Engine) registerDefaultRules() {
    e.rules = append(e.rules,
        &GolangciLintRule{},
        // ...
        &NewRule{}, // Add your new rule here
    )
}

3. (Optional) if your rule requires special formatting, create a new formatter in the formatter package:

   a. Create a new file (e.g., formatter/new_rule.go).

   b. Implement the IssueFormatter interface for your new rule:

   type NewRuleFormatter struct{}
   
   func (f *NewRuleFormatter) Format(
       issue types.Issue,
       snippet *internal.SourceCode,
   ) string {
       // Implement formatting logic for new rule here.
   }

   c. Add the new formatter to the GetFormatter function in formatter/fmt.go.

   func GetFormatter(rule string) IssueFormatter {
       switch rule {
       // ...
       case "new_rule": // Add your new rule here
           return &NewRuleFormatter{}
       default:
           return &DefaultFormatter{}
       }
   }

By following these steps, you can add new lint rules and ensure they are properly formatted when displayed in the CLI.

Available Flags

tlin supports several flags to customize its behavior:

• -timeout <duration>: Set a timeout for the linter (default: 5m). Example: -timeout 1m30s
• -cyclo: Run cyclomatic complexity analysis
• -threshold <int>: Set cyclomatic complexity threshold (default: 10)
• -ignore <rules>: Comma-separated list of lint rules to ignore
• -cfg: Run control flow graph analysis
• -func <name>: Specify function name for CFG analysis
• -fix: Automatically fix issues
• -dry-run: Run in dry-run mode (show fixes without applying them)
• -confidence <float>: Set confidence threshold for auto-fixing (0.0 to 1.0, default: 0.75)

Contributing

We welcome all forms of contributions, including bug reports, feature requests, and pull requests. Please feel free to open an issue or submit a pull request.

Credits

• @GodDrinkTeJAVA - Project name (tlin) suggestion

License

This project is distributed under the MIT License. See LICENSE for more information.