Code Quality

Code Quality

Systematic code improvement through review, refactoring, and debugging with verification gates.

Module Selection

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Core Principles

YAGNI, KISS, DRY - Always honor these.

Be honest, be brutal, straight to the point, and be concise.

Technical correctness over social comfort. Verify before implementing. Ask before assuming. Evidence before claims.

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Code Review

Receiving Feedback

Pattern: READ → UNDERSTAND → VERIFY → EVALUATE → RESPOND → IMPLEMENT

Rules:

• ❌ No performative agreement ("You're right!", "Great point!")
• ❌ No implementation before verification
• ✅ Restate requirement, ask questions, push back with reasoning
• ✅ YAGNI check: grep for usage before implementing suggestions

Sources:

• Human partner → Implement after understanding
• External reviewer → Verify technically before implementing

Requesting Review

When: After major features, before merge, after complex fixes

Process:

1. Get SHAs: BASE_SHA=$(git rev-parse HEAD~1), HEAD_SHA=$(git rev-parse HEAD)
2. Dispatch code-reviewer subagent with: WHAT, PLAN, SHAs, DESCRIPTION
3. Fix Critical immediately, Important before proceeding, note Minor

Verification Gates

Iron Law: NO COMPLETION CLAIMS WITHOUT FRESH VERIFICATION EVIDENCE

Gate: IDENTIFY → RUN → READ → VERIFY → THEN claim

Skip any step = lying, not verifying.

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Refactoring

Mindset

Simplify relentlessly. Preserve behavior religiously. Measure everything.

Every refactoring: small and safe, tested immediately, measurably better.

Protocol

1. Assessment - Baseline metrics, identify smells, classify debt
2. Safety Net - Verify test coverage, add characterization tests
3. Red-Green-Refactor - Write failing test, minimal pass, improve design
4. Pattern Application - SOLID, design patterns, functional transforms
5. Validation - Measure improvements, verify behavior preserved

Code Smells (5 Categories)

1. Bloaters: Long Method, Large Class, Long Parameter List
2. OO Abusers: Switch Statements, Temporary Field
3. Change Preventers: Divergent Change, Shotgun Surgery
4. Dispensables: Duplicate Code, Dead Code, Lazy Class
5. Couplers: Feature Envy, Inappropriate Intimacy

Quick Patterns

OOP: Extract Method, Inline, Replace Temp with Query, Guard Clauses Functional: Map/​Filter/​Reduce, Pure Functions, Composition, Immutability

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Debugging

Core Principle

NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST

Random fixes waste time and create new bugs.

The Four Techniques

1. Systematic Debugging (references/​systematic-debugging.md)

• Phase 1: Root Cause Investigation
• Phase 2: Pattern Analysis
• Phase 3: Hypothesis Testing
• Phase 4: Implementation

2. Root Cause Tracing (references/​root-cause-tracing.md) Trace backward through call stack to find original trigger.

3. Defense-in-Depth (references/​defense-in-depth.md) Validate at every layer: Entry → Business logic → Environment → Debug

4. Verification (references/​verification.md) Run command. Read output. Then claim result.

Quick Reference

Bug → systematic-debugging.md (Phase 1-4)
  Error deep in stack? → root-cause-tracing.md
  Found root cause? → defense-in-depth.md
  About to claim success? → verification.md

Red Flags

Stop if thinking:

• "Quick fix for now, investigate later"
• "Just try changing X and see"
• "It's probably X, let me fix that"
• "Should work now" / "Seems fixed"

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References

Code Review

• references/​code-review-reception.md - Response protocols
• references/​requesting-code-review.md - Request process
• references/​verification-before-completion.md - Verification gates

Refactoring

• references/​oop-refactoring-catalog.md - Martin Fowler's patterns
• references/​functional-refactoring-patterns.md - FP transformations
• references/​code-smells-reference.md - 23 smells, 5 categories
• references/​testing-strategies.md - Characterization tests, TDD

Debugging

• references/​systematic-debugging.md - Four-phase framework
• references/​root-cause-tracing.md - Call stack analysis
• references/​defense-in-depth.md - Multi-layer validation
• references/​verification.md - Verification protocols

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Bottom Line

1. Review: Technical rigor over social performance
2. Refactor: Small, safe, tested, measurable
3. Debug: Root cause first, fix once
4. Always: Evidence before claims

Verify. Question. Then implement. Evidence. Then claim.