dry-code-review

Files (2)

• SKILL.md
• find_duplicates.sh · scripts/

SKILL.md (first lines)

# DRY Code Review Skill

Perform a structured, thorough code review focused on the DRY (Don't Repeat Yourself) principle. The review is planned and tracked via a markdown file in `plans/`.

## Overview

The DRY principle states: "Every piece of knowledge must have a single, unambiguous, authoritative representation within a system." This skill systematically finds violations and recommends fixes.

## Workflow

### Phase 1: Setup & Discovery

1. **Create the tracking plan** in `plans/dry-review-<project-name>.md` using the template below
2. **Inventory the codebase**: List all source files, their languages, sizes, and roles
3. **Identify scope**: Confirm with the user which directories/files to include or exclude (e.g., skip `node_modules`, `vendor`, generated files, test fixtures)

### Phase 2: Automated Scanning

Run the scanning script to find likely duplication:

```bash
bash /path/to/dry-code-review/scripts/find_duplicates.sh <target_directory> [extensions]
```

The script detects:
- Identical or near-identical code blocks (3+ lines repeated)
- Repeated string literals and magic numbers
- Similar function signatures across files
- Repeated boilerplate and configuration patterns

Import/dependency lines are intentionally excluded from the duplicate-lines scan so they don't dominate the output.

### Phase 3: Manual Analysis

After automated scanning, perform deeper analysis by reading the codebase. Look for these DRY violation categories:

#### Category 1: Literal Duplication
- Copy-pasted code blocks (exact or near-exact)
- Repeated string literals / magic numbers
- Duplicate configuration values

#### Category 2: Structural Duplication
- Functions/methods that do the same thing with minor variations
- Repeated conditional logic (same if/else chains)
- Similar class structures that could share a base class or mixin
- Repeated error handling patterns

#### Category 3: Logical Duplication
- Same business logic expressed differently in multiple places
- Repeated validation rules
- Duplicate data transformation pipelines
- Same algorithm implemented in multiple places

#### Category 4: Cross-Cutting Duplication
- Repeated boilerplate across files (logging, auth checks, error wrappers)
- Similar API endpoint handlers
- Repeated test setup/teardown code
- Duplicate build/deploy configuration

### Phase 4: Findings & Recommendations

For each finding, document:

1. **ID**: Sequential identifier (DRY-001, DRY-002, ...)
2. **Category**: Which of the 4 categories above
3. **Severity**: 🔴 High (5+ repetitions or core logic) / 🟡 Medium (2-4 repetitions) / 🟢 Low (minor or cosmetic)
4. **Locations**: File paths and line numbers of all occurrences
5. **Description**: What is duplicated and why it matters
6. **Recommendation**: Specific refactoring approach
7. **Effort**: S / M / L estimate

#### Common Refactoring Recommendations

- **Extract Function/Method**: Pull repeated logic into a shared function
- **Extract Constant/Config**: Replace magic numbers and repeated literals
- **Create Base Class/Mixin**: Share behavior across similar classes
- **Use Higher-Order Functions**: Wrap repeated patterns (decorators, middleware)
- **Create Shared Utility Module**: Centralize cross-cutting concerns
- **Use Templates/Generics**: Parameterize structural duplication
- **Apply Strategy Pattern**: Replace repeated conditional branches
- **Consolidate Configuration**: Single source of truth for settings

### Phase 5: Summary & Prioritization

Update the plan file with:
- Total findings count by category and severity
- A prioritized action list (quick wins first, then high-impact refactors)
- Estimated effort for full remediation
- Risk notes (what could break if refactored carelessly)

## Plan File Template

The plan file MUST be created at `plans/dry-review-<project-name>.md` using this structure:

```markdown
# DRY Code Review: <Project Name>

## Review Metadata
- **Date**: YYYY-MM-DD
- **Reviewer**: Claude (AI-assisted)
- **Scope**: <directories/files reviewed>
- **Languages**: <languages found>
- **Total Files Scanned**: <count>
- **Total Lines of Code**: <count>

## Status
- [ ] Phase 1: Setup & Discovery
- [ ] Phase 2: Automated Scanning
- [ ] Phase 3: Manual Analysis
- [ ] Phase 4: Findings & Recommendations
- [ ] Phase 5: Summary & Prioritization

## Scope Definition
### Included
- <list of included paths>

### Excluded
- <list of excluded paths and reasons>

From espennilsen/pi, MIT.

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