2nd/10_Wiki/Topic_Programming/Architecture/Architectural Violations.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-architectural-violations	Architectural Violations	10_Wiki/Topics	verified	self	Architecture Erosion Architecture Drift Layer Violations Dependency Violations	none	A	0.9	applied	architecture violations erosion drift archunit		2026-05-10	pending	language framework java/kotlin/typescript ArchUnit / Sonargraph / dependency-cruiser

Architectural Violations

매 한 줄

"매 architectural violation 의 intended architecture 와 actual code 사이의 deviation". Perry & Wolf 의 erosion (decay over time) + drift (unauthorized addition) 의 distinguishing — 매 erosion 의 explicit decay, drift 의 silent. 매 modern detection 의 fitness function (ArchUnit, dep-cruiser, Sonargraph) + reflexion model — 매 manual review 의 too-late.

매 핵심

매 violation 의 종류

• Layer violation: domain → infrastructure (wrong direction).
• Module violation: one module imports private internals of another.
• Dependency cycle: A → B → C → A.
• Convention violation: *Service not in service package.
• Forbidden API: java.util.Date, console.log in production code.
• Coupling violation: too many afferent / efferent dependencies.
• Cohesion violation: feature smeared across many modules.
• Cross-bounded-context leakage: shared domain model between contexts.

매 detection mechanism

1. Static structural: ArchUnit, dep-cruiser, Sonargraph (parse + graph).
2. Reflexion model: actual graph diff with intended graph.
3. Runtime: trace analysis (OpenTelemetry) for unexpected service-to-service calls.
4. Reviewer-driven: ADR conformance check in PR.
5. Visualization: dependency matrix, sunburst, codecity.

매 lifecycle

1. Detect (CI fails or alert).
2. Classify (true violation vs intentional exception).
3. Triage (debt vs immediate fix).
4. Fix (refactor or update intended architecture / ADR).
5. Prevent regression (add fitness function).

💻 패턴

Detect layer violation — ArchUnit

@AnalyzeClasses(packages = ["com.acme"], importOptions = [DoNotIncludeTests::class])
class LayerViolationTest {
    @ArchTest
    val domain_independent: ArchRule = noClasses()
        .that().resideInAPackage("..domain..")
        .should().dependOnClassesThat().resideInAnyPackage(
            "..application..", "..infrastructure..", "..web..")
        .because("Domain is the innermost layer (Hexagonal)")

    @ArchTest
    val no_repo_in_controller: ArchRule = noClasses()
        .that().resideInAPackage("..web..")
        .should().dependOnClassesThat().resideInAPackage("..persistence..")
}

Detect cycle — dependency-cruiser (TS)

npx depcruise --validate .dependency-cruiser.cjs src \
  --output-type err-html --output-to depgraph.html
# Exit 1 if cycles found; html visualizes offending edges

Reflexion model — intended vs actual (jQAssistant + Cypher)

// Intended: domain → no-deps; application → domain; infra → application
// Detect any class in :Domain depending on :Infra (forbidden)
MATCH (a:Class)-[:DEPENDS_ON]->(b:Class)
WHERE a.layer = "Domain" AND b.layer = "Infrastructure"
RETURN a.fqn AS violator, b.fqn AS forbidden

Runtime violation — unauthorized service call (OpenTelemetry + Tempo)

# Alert if service A calls service C (intended only A→B, B→C)
sum(rate(traces_spanmetrics_calls_total{
  client="service-a", server="service-c"
}[5m])) > 0

Cyclomatic + afferent/efferent metric (Sonargraph)

<!-- sonargraph-architect rule -->
<architecture>
  <layer name="Domain" />
  <layer name="App" includes="Domain" />
  <layer name="Infra" includes="App" />
  <connector from="App" to="Domain" />
  <connector from="Infra" to="App" />
  <metric type="afferent_coupling" max="20" />
  <metric type="cyclic_groups" max="0" />
</architecture>

Triage workflow — annotate intentional exception

// When violation is *intended* (rare), document explicitly via ADR + suppress
@SuppressArchTest(
    rule = "domain_independent",
    reason = "ADR-0034: bridge to legacy DAO during 6-month migration",
    expiresOn = "2026-12-01"
)
class LegacyBridgeAdapter { /* ... */ }

// Companion test enforces expiry
@ArchTest
val no_expired_suppressions: ArchRule = noClasses()
    .should().beAnnotatedWith(SuppressArchTest::class.java)
    .andShould(haveExpiredSuppression())  // custom condition

Visualize violations — dependency matrix (D3)

// scripts/depmatrix.mjs — render violation heatmap
import { cruise } from "dependency-cruiser";
import fs from "node:fs";
const r = await cruise(["src"], { ruleSet: require("./.dependency-cruiser.cjs") });
const violations = r.output.summary.violations;
const matrix = buildAdjacencyMatrix(r.output.modules, violations);
fs.writeFileSync("violations.json", JSON.stringify(matrix));
// Then render with d3-matrix or observable-plot

CI gating with delta — only new violations fail

# Compare current vs main — fail PR only on new violations (not legacy debt)
npx depcruise src --config .dependency-cruiser.cjs --output-type json > head.json
git checkout main -- .
npx depcruise src --config .dependency-cruiser.cjs --output-type json > main.json
node scripts/diff-violations.mjs main.json head.json  # exit 1 on new violations

Erosion KPI dashboard (per service / quarter)

-- violations_history table (populated nightly by CI)
SELECT
  service,
  DATE_TRUNC('week', detected_at) AS wk,
  COUNT(*) FILTER (WHERE severity='error') AS errs,
  COUNT(*) FILTER (WHERE severity='warn') AS warns
FROM violations_history
WHERE detected_at > NOW() - INTERVAL '12 weeks'
GROUP BY service, wk
ORDER BY service, wk;

매 결정 기준

상황	Approach
New violation detected in PR	Block merge until fixed or ADR exception added
Legacy debt — many existing violations	Baseline & gate on delta (no new)
Intentional bridge	Suppress + ADR + expiry date
Runtime call mismatch	Trace-based alerting + service mesh policy
Unclear if violation	Run reflexion model — document intended first

기본값: ArchUnit/dep-cruiser at PR time + delta gating on legacy code + ADR-tracked suppressions with expiry.

🔗 Graph

• 부모: Software Architecture · Architectural-Constraint-Enforcement
• 변형: Architecture Erosion · Architecture Drift
• 응용: Architecture Review (아키텍처 및 설계 리뷰) · Architecture_Refactor · Technical Debt
• Adjacent: ArchUnit · OpenTelemetry

🤖 LLM 활용

언제: classify violation as erosion vs drift vs intentional, draft suppression ADR with expiry, generate refactor plan from violation report, summarize weekly violations dashboard for tech lead. 언제 X: do not blindly accept LLM "this violation is fine" — every suppression needs ADR + expiry; LLM judgment is suggestion, not authority.

❌ 안티패턴

• Suppression without expiry: permanent escape hatch — original intent lost.
• No baseline: blocking PRs on existing legacy violations buries team.
• Documentation-only intended architecture: cannot detect drift — no ground truth.
• One-shot detection: run once, never again — violations re-grow.
• Fix-the-symptom: rename file vs fix actual coupling.
• Auto-suppress: tool generates suppressions silently — true violations hidden.

🧪 검증 / 중복

• Verified (Perry & Wolf "Foundations for the Study of Software Architecture" 1992, Murphy "Reflexion Models" 1995, ArchUnit / Sonargraph / dependency-cruiser docs).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — erosion vs drift, reflexion model, delta gating