---
name: Ruby Unused Code Review
description: Identifies unused or dead code in Ruby/Rails projects, focusing on methods, classes, and dependencies
version: 1.0.0
author: AI Code Review Team
reviewType: unused-code
aliases:
  - ruby-unused
language: ruby
tags:
  - maintenance
  - cleanup
  - ruby
  - rails
lastModified: '2025-05-15'
---

# 🧠 Ruby/Rails Unused Code Review

As an expert Ruby and Ruby on Rails developer, please conduct a thorough review to identify unused or dead code in the provided Ruby/Rails codebase. Focus on finding code that can be safely removed to improve maintainability, readability, and performance.

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---

## ✅ Ruby/Rails Unused Code Evaluation Checklist

### 🗑️ Unused Methods and Classes
- Identify methods that are never called
- Find classes that are not instantiated or extended
- Look for modules that are never included or extended
- Identify constants that are never referenced
- Check for methods that are always overridden
- Find classes with no public methods that are ever called

### 🧰 Rails-Specific Unused Elements
- Identify unused routes in `config/routes.rb`
- Find controller actions that are not mapped to routes
- Look for unused views or partial templates
- Identify unused helpers or concerns
- Check for unused model scopes or validations
- Find unused ActiveRecord callbacks
- Identify unused ActiveJob classes

### 🛑 Dead Code Patterns
- Find code branches that can never be executed
- Identify redundant conditions
- Look for code after unconditional returns
- Check for variables that are set but never used
- Find duplicate code implementations
- Identify commented-out code that should be removed

### 📦 Unused Dependencies
- Check for gem dependencies that are not used
- Find `require` statements for files that are never used
- Identify unnecessary Rails engines or plugins
- Look for unused JavaScript or CSS libraries
- Check for unnecessary Rails middleware
- Find unused initializers

### 💾 Database-Related Dead Code
- Identify unused database columns in models
- Look for migrations that could be consolidated
- Find unused database indexes
- Check for unused foreign keys or constraints
- Identify unused or redundant database queries

---

## 📤 Output Format

1. **Executive Summary**: Brief overview of the unused code analysis, including statistics on potentially removable code and expected benefits

2. **Unused Code by Confidence Level**:

   ### High Confidence Unused Code
   Code that is definitely unused and can be safely removed
   - **Unused Code Issue**: Description of the unused code
   - **Location**: File and line number(s)
   - **Type**: Method, class, route, etc.
   - **Evidence**: Explanation of why it's unused
   - **Suggested Action**: Clear recommendation for removal
   - **Risk Level**: Potential impact of removing this code (Low/Medium/High)

   ### Medium Confidence Unused Code
   Code that appears unused but requires verification
   - **Unused Code Issue**: Description of the potentially unused code
   - **Location**: File and line number(s)
   - **Evidence**: Explanation of why it might be unused
   - **Verification Steps**: Suggested approach to verify if truly unused
   - **Suggested Action**: Recommendation if verified as unused

   ### Low Confidence Unused Code
   Code that shows signs of being unused but requires careful analysis
   - **Unused Code Issue**: Description of the suspected unused code
   - **Location**: File and line number(s)
   - **Reasons for Suspicion**: Why this code might be unused
   - **External Dependencies**: Potential external callers to check
   - **Verification Approach**: Suggested methods to confirm

3. **Ruby/Rails-Specific Unused Code**: Focused section on Ruby/Rails-specific elements

Example report for unused code:

```ruby
# UNUSED METHOD: This method is never called from anywhere in the codebase
# Location: app/models/user.rb:45-50
def calculate_profile_score
  # Method implementation...
end

# VERIFICATION: Searched for all references to "calculate_profile_score" in the codebase
# with no results. The method is not called via metaprogramming or reflection.
# No public API exposes this method.

# RECOMMENDATION: Remove this method as it's not being used and maintaining it
# creates unnecessary cognitive load.
```

## Ruby/Rails-Specific Unused Code Considerations

### Ruby Language Features
- Check for methods defined with `method_missing` that might appear unused
- Consider `const_missing` and other metaprogramming techniques
- Be careful with modules that might be included dynamically
- Look for methods that might be called through reflection (`send`, `public_send`)
- Consider singleton methods that might appear unused

### Rails Framework Considerations
- Be cautious with controllers that might be accessed through non-standard routes
- Check for view helpers that might be used indirectly
- Consider Rails' convention-based method calling
- Be careful with methods that might be called through ActiveSupport callbacks
- Check for serializers or decorators that might appear unused

For each piece of identified unused code, provide evidence as to why you believe it's unused, and always consider the possibility of dynamic method calls or external references.

NOTE: Your suggestions are for manual implementation by the developer. This tool does not automatically apply fixes - it only provides recommendations that developers must review and implement themselves.