gh-jwplatta-prompt-library-claude-plugins-rubyist/hooks/analyze-and-log-smells.md

Code Smell Logger Hook

This hook analyzes Ruby files after they're written and logs detected code smells to help track refactoring opportunities.

Trigger

• Event: post-write
• Pattern: **/*.rb

Purpose

Maintain a running log of code smells to:

• Track refactoring debt over time
• Prioritize refactoring efforts
• Learn from recurring patterns
• Monitor code quality trends

Analysis Process

1. Detect Code Smells

Analyze the file for common smells based on Sandi Metz's principles:

Complexity Smells:

• Methods longer than 5 lines
• Classes longer than 100 lines
• Cyclomatic complexity > 3
• Nested conditionals (depth > 2)
• Long parameter lists (> 4 parameters)

Design Smells:

• Missing dependency injection
• Feature envy (accessing other objects' data)
• Data clumps (same parameters used together)
• Primitive obsession
• Law of Demeter violations (chained method calls)

OO Design Smells:

• Missing single responsibility
• Unclear public/private interface
• Deep inheritance (> 1 level)
• Missing abstraction opportunities
• Duplication (similar code patterns)

Ruby-Specific Smells:

• Missing frozen_string_literal
• Not using Ruby iterators (using for loops)
• Not using blocks/yield appropriately
• Missing null object pattern where appropriate
• Overly complex conditionals vs polymorphism

2. Calculate Severity

High Priority:

• Multiple responsibilities in one class
• Deep nesting (> 2 levels)
• Methods > 10 lines
• Clear SOLID violations

Medium Priority:

• Methods 6-10 lines
• Missing dependency injection
• Law of Demeter violations
• Primitive obsession

Low Priority:

• Methods exactly 5 lines
• Minor style issues
• Potential improvements (not violations)

3. Log Format

Append to .claude/code-smells.log:

[TIMESTAMP] - [FILE_PATH]
Severity: [HIGH/MEDIUM/LOW]
Smell: [SMELL_NAME]
Location: [CLASS_NAME]#[METHOD_NAME] (lines X-Y)
Description: [Specific issue detected]
Suggestion: [Refactoring approach]
Related Pattern: [POODR principle or pattern]
---

Example Output

2025-11-01 14:23:15 - lib/user_service.rb
Severity: HIGH
Smell: God Object / Multiple Responsibilities
Location: UserService (lines 1-156)
Description: Class has 8 public methods handling authentication, validation, email sending, and database operations
Suggestion: Extract into separate services: UserAuthenticator, UserValidator, UserMailer, UserRepository
Related Pattern: Single Responsibility Principle (POODR Ch. 2)
---

2025-11-01 14:23:15 - lib/user_service.rb
Severity: MEDIUM
Smell: Long Method
Location: UserService#create_user (lines 23-42)
Description: Method is 19 lines, handles validation, creation, and email sending
Suggestion: Extract methods: validate_user_data, persist_user, send_welcome_email
Related Pattern: Small Methods (Sandi's Rules)
---

2025-11-01 14:23:15 - lib/order_processor.rb
Severity: MEDIUM
Smell: Missing Dependency Injection
Location: OrderProcessor#process (line 15)
Description: Hard-coded instantiation of EmailMailer.new inside method
Suggestion: Inject mailer dependency through constructor
Related Pattern: Dependency Injection (POODR Ch. 3)
---

2025-11-01 14:23:15 - lib/payment_handler.rb
Severity: LOW
Smell: Primitive Obsession
Location: PaymentHandler#validate_card (lines 8-12)
Description: Using string for credit card number validation
Suggestion: Create CreditCard value object with validation
Related Pattern: Value Object pattern
---

Response to User

After logging, provide a brief summary:

Code Smell Analysis Complete

Analyzed: [file_path]

Detected Issues:

• 1 High Priority: God Object in UserService
• 2 Medium Priority: Long method, missing DI
• 1 Low Priority: Primitive obsession

Top Recommendation: Extract UserService into separate concerns following Single Responsibility Principle.

Full details logged to .claude/code-smells.log

Quick Actions:

• Run /refactor to get detailed refactoring plan
• Run /review-ruby for comprehensive code review
• View log: cat .claude/code-smells.log | tail -20

Log Management

View Recent Smells

# Last 20 entries
tail -20 .claude/code-smells.log

# Smells from specific file
grep "lib/user.rb" .claude/code-smells.log

# High priority only
grep "Severity: HIGH" .claude/code-smells.log

# By smell type
grep "Smell: Long Method" .claude/code-smells.log

Generate Summary Report

# Count by severity
grep -c "Severity: HIGH" .claude/code-smells.log
grep -c "Severity: MEDIUM" .claude/code-smells.log
grep -c "Severity: LOW" .claude/code-smells.log

# Most common smells
grep "Smell:" .claude/code-smells.log | sort | uniq -c | sort -rn

Configuration

Customize in .claude/settings.json:

{
  "plugins": {
    "rubyist": {
      "codeSmellLogging": {
        "enabled": true,
        "logPath": ".claude/code-smells.log",
        "severityThreshold": "MEDIUM",
        "excludePatterns": [
          "**/*_spec.rb",
          "db/migrate/**",
          "lib/generated/**"
        ],
        "autoRefactorSuggestions": true
      }
    }
  }
}

Integration with Refactoring Workflow

The log helps prioritize refactoring:

1. Review accumulated smells weekly/sprint
2. Prioritize by frequency (same smell in multiple files)
3. Track improvements (smell resolution over time)
4. Learn patterns (recurring issues suggest training needs)

Educational Benefit

Over time, the log becomes a learning tool:

• See which smells occur most frequently
• Understand which POODR principles need focus
• Track improvement in code quality
• Share patterns with team

Privacy Note

The log is local to the repository and should be added to .gitignore unless team wants to track collectively:

# .gitignore
.claude/code-smells.log

Or commit for team awareness:

# Track team code quality
!.claude/code-smells.log