name: check-encapsulation
description: Analyzes PHP code for encapsulation violations. Detects public mutable state, exposed internals, Tell Don't Ask violations, getter/setter abuse, and information hiding breaches.
Encapsulation Analyzer
Overview
This skill analyzes PHP codebases for encapsulation violations — situations where internal state is exposed, getters/setters replace behavior, or the "Tell, Don't Ask" principle is violated.
When to Use
- Reviewing Domain layer entities and aggregates
- Detecting anemic domain models
- Checking for Law of Demeter violations
- Auditing collection exposure patterns
- Evaluating getter/behavior ratio in entities
Encapsulation Principles
| Principle |
Description |
Violation Indicator |
| Information Hiding |
Internal state not exposed |
Public properties, many getters |
| Tell Don't Ask |
Objects perform actions, not expose data |
Getter chains, external decisions |
| Behavioral Richness |
Objects have behavior, not just data |
Anemic domain model |
| Invariant Protection |
State changes validate constraints |
Public setters without validation |
Analysis Approach
- Phase 1 — Public Mutable State: Scan Domain entities for non-readonly public properties
- Phase 2 — Getter/Setter Abuse: Count getters vs behavior methods, flag anemic entities
- Phase 3 — Tell Don't Ask: Detect getter chains and external conditionals on object state
- Phase 4 — Collection Exposure: Find methods returning internal arrays/collections directly
- Phase 5 — Exposed Internals: Check for reflection usage, debug methods, mutable object returns
- Phase 6 — Constructor Issues: Flag too many dependencies, complex construction without factories
Detection Rules
| ID |
Pattern |
Grep Target |
| ENC-01 |
Public mutable props |
public string|public int|public array in Domain (exclude readonly) |
| ENC-02 |
Setter methods |
public function set[A-Z] in Entity/Aggregate |
| ENC-03 |
Getter chains |
->get[A-Z].*->get[A-Z].*->get[A-Z] |
| ENC-04 |
External conditionals |
if \(\$.*->get[A-Z].*=== |
| ENC-05 |
Switch on state |
switch \(\$.*->get[A-Z]|match \(\$.*->get[A-Z] |
| ENC-06 |
Collection return |
public function get.*\(\): array in Entity |
| ENC-07 |
Doctrine exposure |
public function get.*\(\): Collection in Domain |
| ENC-08 |
Reflection access |
ReflectionClass|ReflectionProperty|setAccessible |
| ENC-09 |
Debug exposure |
public function toArray\(\)|dump\(\)|debug\(\) in Domain |
| ENC-10 |
Complex construction |
new [A-Z].*Entity\(|new [A-Z].*Aggregate\( in Application |
Severity Classification
| Issue |
Severity |
| Public mutable state in Entity |
Critical |
| Collection mutated externally |
Critical |
| Anemic entity (ratio > 5.0) |
Critical |
| Tell Don't Ask violation |
Major |
| Getter chain (3+ levels) |
Major |
| Internal array returned |
Major |
| Setter in Aggregate |
Minor |
| Reflection in non-test code |
Minor |
Report Format
# Encapsulation Analysis Report
## Summary
| Issue Type | Critical | Warning | Info |
|------------|----------|---------|------|
| Public Mutable State | N | N | - |
| Getter/Setter Abuse | N | N | N |
| Tell Don't Ask | N | N | - |
| Collection Exposure | N | N | - |
| Exposed Internals | N | N | N |
**Encapsulation Score: X%**
## Findings
### [ID]: [Title]
- **File:** `path:line`
- **Issue:** [Description]
- **Code:** [Problematic snippet]
- **Expected:** [Correct pattern]
- **Skills:** [Related generator skills]
## Getter/Behavior Ratio
| Entity | Getters | Setters | Behavior | Ratio | Status |
|--------|---------|---------|----------|-------|--------|
**Target:** Ratio < 2.0
## Refactoring Recommendations
### Immediate
1. Make all entity properties private
2. Replace setters with behavior methods
3. Return collection copies, not references
### Short-term
4. Extract Value Objects for validated data
5. Add factory methods for complex construction
6. Remove getter chains (add shortcut methods)
### Long-term
7. Review anemic entities for missing behavior
8. Consider CQRS to separate read/write models
Integration
Works with:
detect-code-smells — Feature Envy, Anemic Modelstructural-auditor — DDD compliancecreate-entity — Generate rich entitiescreate-value-object — Encapsulated value types
References
references/patterns.md — detailed detection patterns with code examples, report format samples, metrics examples, and rich entity template- "Tell, Don't Ask" — Martin Fowler
- "Anemic Domain Model" — Martin Fowler
- "Object-Oriented Software Construction" (Bertrand Meyer)
- "Elegant Objects" (Yegor Bugayenko)
By