# Architecture Audit Report

**Branch**: fix/tech-debt-v0.3.2
**Base**: main
**Date**: 2025-12-08 20:47

---

## Summary of Changes

This branch includes 6 commits focused on technical debt reduction:

| Commit | Description |
|--------|-------------|
| `ee9d13b` | refactor(types): add explicit row types for repository database access |
| `724b055` | docs: fix incorrect getMaxDepth complexity claim in invariants |
| `ae29b02` | perf: replace getQueueStats() with getQueueSize() |
| `413489c` | feat(db): add CHECK constraint on resolution column |
| `52d366c` | refactor: make MAX_DEPENDENCY_CHAIN_DEPTH configurable |
| `1462f85` | docs: update TASK_ARCHITECTURE.md line references after handler decomposition |

### Files Changed
- `docs/architecture/HANDLER-DECOMPOSITION-INVARIANTS.md`
- `docs/architecture/TASK_ARCHITECTURE.md`
- `src/implementations/database.ts`
- `src/implementations/dependency-repository.ts`
- `src/implementations/task-repository.ts`
- `src/services/handlers/dependency-handler.ts`
- `src/services/handlers/queue-handler.ts`

---

## BLOCKING Issues in Your Changes

No blocking issues found. All changes follow established architectural patterns.

---

## HIGH/MEDIUM Issues in Code You Touched (Should Fix)

### 1. [MEDIUM] Unused Method After Refactoring
**File**: `/workspace/delegate/src/services/handlers/queue-handler.ts:352`
**Category**: Dead Code

The new `getQueueSize()` method is defined but never called anywhere in the codebase:

```typescript
getQueueSize(): number {
  return this.queue.size();
}
```

**Analysis**: 
- The old `getQueueStats()` returned `{ size: number; tasks: readonly any[] }` 
- The new `getQueueSize()` returns only `number`
- No callers exist for either method (confirmed via grep search)

**Recommendation**: Either:
1. Remove the method entirely if not needed
2. Add a caller if this method serves a purpose
3. Document why the method exists (monitoring, future use, etc.)

**Severity**: MEDIUM - Dead code, but harmless

---

### 2. [LOW] Type Assertion in TaskRow Without Runtime Validation
**File**: `/workspace/delegate/src/implementations/task-repository.ts:240-241`
**Category**: Type Safety

The `rowToTask` method uses type assertions for enum-like values:

```typescript
worktreeCleanup: (row.worktree_cleanup || 'auto') as 'auto' | 'keep' | 'delete',
mergeStrategy: (row.merge_strategy || 'pr') as 'auto' | 'pr' | 'manual' | 'patch',
```

**Analysis**:
- Database could contain invalid values (though unlikely)
- No runtime validation before assertion
- If invalid data exists, it silently passes through

**Recommendation**: Consider adding runtime validation or using a schema validation library for database reads. This follows the "parse, don't validate" principle from CLAUDE.md.

**Severity**: LOW - Database CHECK constraints provide some protection, and values are already validated at write time.

---

### 3. [LOW] DependencyRow.resolution Type Not Fully Typed
**File**: `/workspace/delegate/src/implementations/dependency-repository.ts:25-26`
**Category**: Type Safety

```typescript
interface DependencyRow {
  // ...
  readonly resolution: string;  // Should be literal union type
}
```

**Analysis**:
- The `resolution` field is typed as `string` instead of `'pending' | 'completed' | 'failed' | 'cancelled'`
- The database now has a CHECK constraint (added in this branch) that validates these values
- The `rowToDependency` method casts this to the proper union type

**Recommendation**: Update the interface to use the proper union type for defense-in-depth:

```typescript
readonly resolution: 'pending' | 'completed' | 'failed' | 'cancelled';
```

**Severity**: LOW - The CHECK constraint provides database-level protection, and the cast in `rowToDependency` enforces the type at runtime.

---

## Pre-existing Issues (Not Blocking)

### 1. [INFO] Deprecated Methods Still Present
**File**: `/workspace/delegate/src/services/handlers/queue-handler.ts:228-282`
**Category**: Technical Debt

Two methods are marked as deprecated but still present:
- `getNextTask()` (line 231) - Should use `NextTaskQuery` event
- `requeueTask()` (line 256) - Should use `RequeueTask` event

**Analysis**: These are pre-existing and marked for removal. Not related to this branch's changes.

---

### 2. [INFO] Type Casting in Event Handling
**File**: `/workspace/delegate/src/services/handlers/queue-handler.ts:158-186`
**Category**: Type Safety

The `handleNextTaskQuery` method uses `(event as any).__correlationId` pattern:

```typescript
const correlationId = (event as any).__correlationId;
if (correlationId && this.eventBus && 'respondError' in this.eventBus) {
  (this.eventBus as any).respondError(correlationId, result.error);
}
```

**Analysis**: This is pre-existing technical debt. The correlation ID pattern uses dynamic typing that bypasses TypeScript's type system.

---

## Architecture Quality Assessment

### Positive Changes

1. **Type Safety Improvements** (Commit `ee9d13b`)
   - Added explicit `DependencyRow` and `TaskRow` interfaces
   - Replaced `Record<string, any>` with proper typed interfaces
   - Follows the global CLAUDE.md principle: "Type everything - Use explicit types, avoid dynamic types"

2. **Database Defense-in-Depth** (Commit `413489c`)
   - Added CHECK constraint on `resolution` column
   - Proper SQLite migration pattern with table recreation
   - Preserves existing data safely

3. **Configurable Constants** (Commit `52d366c`)
   - `MAX_DEPENDENCY_CHAIN_DEPTH` now configurable via `DependencyHandlerOptions`
   - Follows dependency injection pattern
   - Improves testability

4. **Performance Optimization** (Commit `ae29b02`)
   - Removed unnecessary array copy in `getQueueStats()`
   - New `getQueueSize()` only returns count
   - Note: Method appears unused

5. **Documentation Accuracy** (Commits `724b055`, `1462f85`)
   - Fixed incorrect complexity claim in invariants doc
   - Updated line references to match actual code

### Design Pattern Adherence

| Pattern | Status | Notes |
|---------|--------|-------|
| Repository Pattern | PASS | Clean separation in task/dependency repos |
| Event-Driven Architecture | PASS | Handlers communicate via EventBus |
| Result Types | PASS | All public methods return `Result<T>` |
| Dependency Injection | PASS | `DependencyHandlerOptions` added correctly |
| Immutability | PASS | Row types are `readonly` |
| Factory Pattern | PASS | `DependencyHandler.create()` async factory |

### SOLID Principle Compliance

| Principle | Status | Notes |
|-----------|--------|-------|
| Single Responsibility | PASS | Each handler has focused responsibility |
| Open/Closed | PASS | Options interface allows extension |
| Liskov Substitution | N/A | No inheritance in changes |
| Interface Segregation | PASS | Interfaces are focused |
| Dependency Inversion | PASS | Dependencies injected via constructor |

---

## Summary

**Your Changes**:
- BLOCKING: 0
- MEDIUM: 1 (unused method)
- LOW: 2 (type safety improvements possible)

**Pre-existing Issues**:
- INFO: 2 (deprecated methods, type casting)

**Architecture Score**: 9/10

The branch demonstrates excellent architecture practices:
- Type safety improvements with explicit row types
- Database-level defense-in-depth with CHECK constraints
- Proper configuration injection pattern
- Accurate documentation updates

The only concern is the unused `getQueueSize()` method, which should either be removed or have a documented purpose.

---

## Merge Recommendation

**APPROVED**

This branch improves code quality and follows all established architectural patterns. The changes are well-structured, properly typed, and include appropriate documentation updates. No blocking issues identified.

Minor recommendation: Consider removing or documenting the purpose of `getQueueSize()` before or after merge.
