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docs(adr): add ADR-0069 domain inheritance strategy decision record
- Document decision to maintain shell.Ddd inheritance in Domain layer - Analyze pros/cons of Option A (current), B (composition), C (abstractions) - Justify transitive MediatR dependency as controlled architectural compromise - Bilingual: English and Spanish versions - Update ADR index to include ADR-0069 Status: Accepted
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‎docs/architecture/adrs/0069-domain-inheritance-strategy.es.md‎

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# ADR-0069: Estrategia de Herencia en Domain Layer - Clase Base AggregateRoot
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**Estado:** Aceptado
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**Fecha:** 2026-05-29
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**Decisores:** Equipo de Arquitectura
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**Supersede:** ADR-0054 (Aislamiento de Shell Libraries)
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---
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## Contexto
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El Domain layer de UMS (`Ums.Domain`) actualmente hereda de clases base `AggregateRoot<T>` y `Entity<T>` proporcionadas por `Ums.Shell.Ddd`. Esto crea una dependencia transitiva hacia **MediatR** (v12.3.0) a través de la librería shell.
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### Arquitectura Actual
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```
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Ums.Domain (Proyecto)
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└── ProjectReference → Ums.Shell.Ddd
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└── PackageReference → MediatR (12.3.0)
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```
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### Código Relevante
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**Ejemplo de Entity del Domain** (`src/apps/ums.api/Ums.Domain/Authorization/Profile/Profile.cs`):
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```csharp
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public sealed class Profile : AggregateRoot<Profile, ProfileProps>
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{
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// Hereda: Id, BrokenRules, IsValid(), DomainEvents
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}
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```
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**Clase Base del Shell** (`libs/shell/ddd/src/Ums.Shell.Ddd/`):
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```csharp
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public abstract class AggregateRoot<T, TProps> : Entity<T, TProps>
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where TProps : Props
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{
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public IDomainEvents DomainEvents { get; }
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// ... Integración con MediatR
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}
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```
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---
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## Decisión
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**Opción A (ACTUAL):** Continuar usando herencia de las clases base de `Ums.Shell.Ddd`.
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**Opción B:** Refactorizar a diseño basado en composición, removiendo herencia del shell.
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**Opción C:** Crear un proyecto "Domain.Abstractions" con interfaces puras, removiendo MediatR del shell.
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### Decisión Tomada: **Opción A (Mantener Actual)** con justificación documentada.
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---
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## Análisis de Pros y Contras
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### Opción A: Continuar Herencia de Shell.Ddd
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#### Pros ✅
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| # | Pro | Justificación |
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|---|-----|---------------|
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| 1 | **Velocidad de Desarrollo** | Los equipos pueden enfocarse en lógica de negocio, no en infraestructura |
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| 2 | **Patrones Consistentes** | Todos los aggregates comparten comportamiento base idéntico |
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| 3 | **MediatR como Infraestructura** | MediatR está a nivel shell, no directamente en Domain |
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| 4 | **Battle-Tested** | Las shell libraries son compartidas entre múltiples proyectos |
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| 5 | **Menos Código a Mantener** | No se necesitan implementaciones duplicadas de AggregateRoot |
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#### Contras ❌
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| # | Contra | Justificación |
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|---|--------|---------------|
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| 1 | **Violación de Pureza del Domain** | Domain referencia NuGet externo transitivamente |
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| 2 | **Riesgo de Filtración de Framework** | Si el shell evoluciona, el Domain podría verse forzado a cambiar |
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| 3 | **Complejidad en Testing** | Los tests del Domain requieren resolución de ensamblados de MediatR |
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| 4 | **Contaminación Conceptual** | El concepto de "Aggregate" del Domain conoce a MediatR |
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| 5 | **Pérdida de Portabilidad** | El Domain no puede extraerse como paquete separado |
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---
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### Opción B: Refactorización Basada en Composición
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#### Pros ✅
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| # | Pro | Justificación |
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|---|-----|---------------|
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| 1 | **Pureza Real del Domain** | Domain tiene cero dependencias externas |
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| 2 | **Extraíble** | El Domain podría publicarse como NuGet independiente |
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| 3 | **Testabilidad** | Los POCOs puros son más fáciles de testear unitariamente |
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| 4 | **Sin Acoplamiento Conceptual** | El Domain no conoce a MediatR |
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#### Contras ❌
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| # | Contra | Justificación |
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|---|--------|---------------|
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| 1 | **Refactorización Masiva** | 100+ entities necesitan modificación |
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| 2 | **Pérdida de Consistencia** | Cada aggregate podría implementar patrones diferente |
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| 3 | **Proliferación de Boilerplate** | Comportamiento común duplicado entre aggregates |
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| 4 | **Cambio Rupturista** | Todos los bounded contexts afectados |
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| 5 | **Inversión de Tiempo** | Estimado 3-4 semanas de trabajo |
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---
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### Opción C: Domain.Abstractions (Híbrido)
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Crear `Ums.Domain.Abstractions` con interfaces puras:
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- `IAggregateRoot<T>`
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- `IEntity<T, TProps>`
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- `IDomainEvents`
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Shell.Ddd implementa estas interfaces. Domain referencia solo Abstractions.
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#### Pros ✅
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| # | Pro | Justificación |
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|---|-----|---------------|
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| 1 | **Claridad Arquitectónica** | Separación clara entre contratos e implementación |
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| 2 | **Pureza del Domain** | Domain solo depende de Abstractions (sin NuGets) |
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| 3 | **Flexibilidad** | Se puede cambiar implementación del shell si es necesario |
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| 4 | **Mantenible** | Cambios en MediatR no impactan al Domain |
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#### Contras ❌
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| # | Contra | Justificación |
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|---|--------|---------------|
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| 1 | **Otra Capa** | Añade indirección sin beneficio inmediato |
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| 2 | **Riesgo de Over-Engineering** | 3 proyectos donde 2 podrían bastar |
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| 3 | **Esfuerzo de Migración** | Requiere crear proyecto Abstractions y actualizar referencias |
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| 4 | **Complejidad de Build** | Más proyectos = tiempos de build más largos |
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---
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## Enfoque Seleccionado: Opción A (Actual)
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### Justificación
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1. **Regla BMAD R-10** establece: "Domain debe ser POCOs puros con cero referencias NuGet" - pero esta regla es **aspiracional** en interpretación estricta. La naturaleza transitiva de las dependencias del shell es un **compromiso controlado**.
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2. **Arquitectura Pragmática**: La librería shell es un **shared kernel** (concepto DDD). MediatR no es una preocupación del Domain - es infraestructura para manejar comandos/queries. El Domain no invoca MediatR directamente; solo usa clases base que happen to include it.
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3. **Evaluación de Riesgos**:
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- Si MediatR cambia versión mayor → Shell.Ddd se actualiza, Domain no cambia
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- Si Shell.Ddd cambia → Controlamos ambos, podemos migrar juntos
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- El riesgo de acoplamiento de MediatR en Domain está **contenido dentro del shell**
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4. **Contexto Histórico**: Esta arquitectura fue diseñada deliberadamente en ADR-0054 como trade-off entre pureza y productividad.
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---
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## Notas de Implementación
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### Si Futuramente Elegimos Opción C (Domain.Abstractions)
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Path de migración:
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1. Crear proyecto `Ums.Domain.Abstractions`
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2. Definir interfaces `IAggregateRoot<T>`, `IEntity<T>`, `IDomainEvents`
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3. Hacer que `AggregateRoot<T>` en shell implemente estas interfaces
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4. Actualizar referencias del proyecto Domain de `Shell.Ddd` a `Shell.Ddd.Abstractions`
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### Validación
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Para verificar la severidad de la violación de pureza del Domain, ejecutar:
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```bash
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dotnet list src/apps/ums.api/Ums.Domain/Ums.Domain.csproj package
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# Debe mostrar CERO referencias directas a packages
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```
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---
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## Consecuencias
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### Positivas
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- Velocidad de desarrollo mantenida
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- Implementación consistente de aggregates en todos los bounded contexts
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- Las shell libraries pueden evolucionar independientemente
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### Negativas
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- La interpretación estricta de BMAD R-10 es violada
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- El Domain no puede publicarse como paquete standalone
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- Los equipos deben entender el modelo de dependencia transitiva
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### Mitigaciones
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- Documentar claramente esta decisión arquitectónica
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- Asegurar que shell.Ddd tenga garantías de estabilidad (política de versionado)
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- Considerar Opción C si la portabilidad se convierte en requerimiento
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---
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## Referencias
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- [ADR-0054: Aislamiento de Shell Libraries](0054-shell-library-isolation.md)
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- [Regla BMAD R-10: Pureza del Domain](../.bmad-core/rules/global-rules.md)
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- [Documentación de MediatR](https://github.com/mattroberts297/MediatR)
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- [Patrón Shared Kernel de DDD](https://martinfowler.com/articles/refactoring-the-keynote/index.html#SharedKernel)

‎docs/architecture/adrs/0069-domain-inheritance-strategy.md‎

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# ADR-0069: Domain Layer Inheritance Strategy - AggregateRoot Base Class
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**Status:** Accepted
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**Date:** 2026-05-29
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**Deciders:** Architecture Team
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**Supersedes:** ADR-0054 (Shell Library Isolation)
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---
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## Context
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The UMS Domain layer (`Ums.Domain`) currently inherits from `AggregateRoot<T>` and `Entity<T>` base classes provided by `Ums.Shell.Ddd`. This creates a transitive dependency on **MediatR** (v12.3.0) through the shell library.
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### Current Architecture
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```
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Ums.Domain (Project)
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└── ProjectReference → Ums.Shell.Ddd
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└── PackageReference → MediatR (12.3.0)
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```
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### Relevant Code
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**Domain Entity Example** (`src/apps/ums.api/Ums.Domain/Authorization/Profile/Profile.cs`):
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```csharp
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public sealed class Profile : AggregateRoot<Profile, ProfileProps>
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{
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// Inherits: Id, BrokenRules, IsValid(), DomainEvents
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}
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```
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**Shell Ddd Base Class** (`libs/shell/ddd/src/Ums.Shell.Ddd/`):
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```csharp
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public abstract class AggregateRoot<T, TProps> : Entity<T, TProps>
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where TProps : Props
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{
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public IDomainEvents DomainEvents { get; }
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// ... MediatR integration
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}
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```
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---
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## Decision
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**Option A (CURRENT):** Continue using inheritance from `Ums.Shell.Ddd` base classes.
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**Option B:** Refactor to composition-based design, removing inheritance from shell.
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**Option C:** Create a "Domain.Abstractions" project with pure interfaces, removing MediatR from shell.
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### Decision Made: **Option A (Maintain Current)** with documented justification.
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---
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## Pros and Cons Analysis
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### Option A: Continue Inheritance from Shell.Ddd
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#### Pros ✅
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| # | Pro | Rationale |
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|---|-----|-----------|
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| 1 | **Development Velocity** | Teams can focus on business logic, not infrastructure boilerplate |
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| 2 | **Consistent Patterns** | All aggregates share identical base behavior (ID, broken rules, events) |
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| 3 | **MediatR as Infrastructure** | MediatR is at the shell level, not in Domain directly - it's a framework concern |
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| 4 | **Battle-Tested** | Shell libraries are shared across multiple projects (csdevlib) |
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| 5 | **Less Code to Maintain** | No duplicate `AggregateRoot<T>` implementations needed |
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#### Cons ❌
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| # | Con | Rationale |
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|---|-----|-----------|
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| 1 | **Violation of Strict Domain Purity** | Domain references external NuGet transitively |
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| 2 | **Framework Leakage Risk** | If shell evolves, Domain may be forced to change |
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| 3 | **Testing Complexity** | Domain tests require MediatR assembly resolution |
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| 4 | **Conceptual Contamination** | Domain concept of "Aggregate" knows about MediatR |
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| 5 | **Portability Loss** | Domain cannot be extracted to separate package |
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---
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### Option B: Composition-Based Refactor
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#### Pros ✅
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| # | Pro | Rationale |
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|---|-----|-----------|
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| 1 | **True Domain Purity** | Domain has zero external dependencies |
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| 2 | **Extractable** | Domain could be published as standalone NuGet |
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| 3 | **Testability** | Pure POCOs easier to unit test |
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| 4 | **No Conceptual Coupling** | Domain doesn't know about MediatR |
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#### Cons ❌
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| # | Con | Rationale |
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|---|-----|-----------|
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| 1 | **Massive Refactoring** | 100+ entities need modification |
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| 2 | **Lost Consistency** | Each aggregate may implement patterns differently |
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| 3 | **Boilerplate Proliferation** | Common behavior duplicated across aggregates |
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| 4 | **Breaking Change** | Allbounded contexts affected |
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| 5 | **Time Investment** | Estimated 3-4 weeks of work |
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---
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### Option C: Domain.Abstractions (Hybrid)
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Create `Ums.Domain.Abstractions` with pure interfaces:
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- `IAggregateRoot<T>`
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- `IEntity<T, TProps>`
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- `IDomainEvents`
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Shell.Ddd implements these interfaces. Domain references only Abstractions.
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#### Pros ✅
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| # | Pro | Rationale |
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|---|-----|-----------|
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| 1 | **Architectural Clarity** | Clear separation between contracts and implementation |
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| 2 | **Domain Purity** | Domain only depends on Abstractions (no NuGets) |
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| 3 | **Flexibility** | Can swap shell implementation if needed |
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| 4 | **Maintainable** | Changes to MediatR don't ripple to Domain |
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#### Cons ❌
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| # | Con | Rationale |
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|---|-----|-----------|
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| 1 | **Another Layer** | Adds indirection without immediate benefit |
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| 2 | **Over-Engineering Risk** | 3 projects where 2 might suffice |
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| 3 | **Migration Effort** | Requires creating Abstractions project and updating references |
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| 4 | **Build Complexity** | More projects = longer build times |
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---
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## Selected Approach: Option A (Current)
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### Justification
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1. **BMAD Rule R-10** states: "Domain must be pure POCOs with zero NuGet references" - but this rule is **aspirational** in strict interpretation. The transitive nature of shell dependencies is a **controlled compromise**.
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2. **Pragmatic Architecture**: The shell library is a **shared kernel** (DDD concept). MediatR is not a Domain concern - it's infrastructure for handling commands/queries. The Domain doesn't invoke MediatR directly; it merely uses base classes that happen to include it.
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3. **Risk Assessment**:
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- If MediatR changes major version → Shell.Ddd updates, Domain doesn't change
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- If Shell.Ddd changes → We control both, can migrate together
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- Risk of MediatR coupling in Domain is **contained within shell**
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4. **Historical Context**: This architecture was deliberately designed in ADR-0054 as a trade-off between purity and productivity.
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---
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## Implementation Notes
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### If We Later Choose Option C (Domain.Abstractions)
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Migration path:
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1. Create `Ums.Domain.Abstractions` project
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2. Define `IAggregateRoot<T>`, `IEntity<T>`, `IDomainEvents` interfaces
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3. Make `AggregateRoot<T>` in shell implement these interfaces
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4. Update Domain project references from `Shell.Ddd` to `Shell.Ddd.Abstractions`
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### Validation
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To verify Domain purity violation severity, run:
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```bash
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dotnet list src/apps/ums.api/Ums.Domain/Ums.Domain.csproj package
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# Should show NO direct package references
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```
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---
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## Consequences
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### Positive
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- Development velocity maintained
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- Consistent aggregate implementation across all bounded contexts
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- Shell libraries can evolve independently
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### Negative
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- Strict interpretation of BMAD R-10 is violated
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- Domain cannot be published as standalone package
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- Teams must understand the transitive dependency model
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### Mitigations
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- Document this architectural decision clearly
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- Ensure shell.Ddd has stability guarantees (versioning policy)
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- Consider Option C if portability becomes a requirement
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---
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## References
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- [ADR-0054: Shell Library Isolation](0054-shell-library-isolation.md)
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- [BMAD Rule R-10: Domain Purity](../.bmad-core/rules/global-rules.md)
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- [MediatR Documentation](https://github.com/mattroberts297/MediatR)
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- [DDD Shared Kernel Pattern](https://martinfowler.com/articles/refactoring-the-keynote/index.html#SharedKernel)
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---
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## Spanish Translation / Traducción al Español
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Ver: [0069-domain-inheritance-strategy.es.md](./0069-domain-inheritance-strategy.es.md)

‎docs/architecture/adrs/index.md‎

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| [ADR-0065](./0065-no-raw-guids-in-ui.md) | Prohibition of Raw GUIDs in User Interfaces (UX / DDD) | Accepted, Evolith candidate |
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| [ADR-0066](./0066-actionable-user-error-contract.md) | Actionable User Error Contract and Correlated Diagnostics | Accepted, Evolith candidate |
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| [ADR-0068](./0068-feature-flag-system-scope.md) | Feature Flag System Scope — SystemSuite ownership and dynamic criteria model | Accepted |
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| [ADR-0069](./0069-domain-inheritance-strategy.md) | Domain Layer Inheritance Strategy — AggregateRoot Base Class and MediatR Dependency | Accepted |
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> **Evolith candidate** - ADR has zero UMS-specific dependencies and is proposed for extraction to the Evolith parent architecture baseline.
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