cargo-rust-unused

A CLI tool for detecting unused code in Rust projects. This tool helps you maintain clean and efficient codebases by identifying:

• Unused dependencies in Cargo.toml
• Unused functions and methods
• Unused modules

Features

• 🔍 Analyzes Rust source code using syn for accurate parsing
• 📦 Detects unused dependencies in Cargo.toml
• 🚀 Fast and efficient file traversal
• 💡 Smart detection of unused code items
• 🎨 Beautiful colored output
• 📊 Optional JSON output for CI integration

Installation

From crates.io

coming soon

From Source

# Clone the repository
git clone https://github.com/yourusername/cargo-rust-unused
cd cargo-rust-unused

# Build and install locally
cargo install --path .

Usage

The tool can be used in two ways:

1. As a Cargo Subcommand

cargo rust-unused [OPTIONS]

2. As a Standalone Binary

cargo-rust-unused [OPTIONS]

Options

• --path <PATH>: Path to the Rust project (default: current directory)
• --format <FORMAT>: Output format [text|json] (default: text)
• --include-private: Include private items in the analysis
• --help: Print help information
• --version: Print version information

Example Usage

1. Analyze Current Project

# Navigate to your Rust project
cd my-rust-project

# Run the analysis
cargo rust-unused

2. Analyze with JSON Output

cargo rust-unused --format json

3. Analyze Specific Project Path

cargo rust-unused --path ~/projects/my-rust-project

4. Save Analysis Results

# Save as text
cargo rust-unused > analysis_report.txt

# Save as JSON
cargo rust-unused --format json > analysis_report.json

Example Output

🔍 Analyzing project...

Unused Dependencies:
  - regex
  - serde_yaml

Unused Functions:
  - fn unused_utility()
  - fn deprecated_function()

Unused Modules:
  - mod old_features

JSON Output Format

{
  "unused_dependencies": ["regex", "serde_yaml"],
  "unused_functions": ["fn unused_utility", "fn deprecated_function"],
  "unused_modules": ["mod old_features"]
}

Integration with CI/CD

You can integrate the tool into your CI/CD pipeline. Here's an example GitHub Actions workflow:

name: Code Analysis

on: [push, pull_request]

jobs:
  unused-code-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2

      - name: Install cargo-rust-unused
        run: cargo install --path .

      - name: Run Analysis
        run: |
          cargo rust-unused --format json > analysis.json

      - name: Check Results
        run: |
          if [ "$(jq '.unused_dependencies | length' analysis.json)" -gt 0 ]; then
            echo "Warning: Found unused dependencies!"
            exit 1
          fi

Best Practices

1. Regular Usage:

   • Run before committing changes
   • Include in pre-commit hooks
   • Run as part of code review process

2. Handling Results:

   • Review unused dependencies first (they increase build time)
   • Check unused functions for potential dead code
   • Verify unused modules aren't needed for future use

3. False Positives:

   • Some items might be used indirectly (through macros or reflection)
   • Dependencies might be needed for dev/test environments
   • Consider using #[allow(dead_code)] for intentionally unused items

Troubleshooting

Common Issues

1. Tool Not Finding Files:

   • Ensure you're in a Rust project directory
   • Check if Cargo.toml exists
   • Verify src directory exists

2. Incorrect Results:

   • Update to the latest version
   • Try with --include-private flag
   • Check if code uses macros or dynamic dispatch

Error Messages

Error: Not a Cargo project: no Cargo.toml found
Solution: Run from a Rust project directory

Error: No src directory found
Solution: Create src directory or check path

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. Here's how you can contribute:

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.