Rule Template Inheritance

Overview

This skill defines how to implement inheritance between rule templates so client-specific templates can extend base/system templates with controlled customization.

It introduces parent-child template relationships while preserving immutable rule versioning and deterministic rule evaluation.

When to Use

Use this skill when:

• •Adding parentTemplateId support to rule template modeling
• •Implementing base/system templates with tenant customizations
• •Merging inherited parent conditions with child conditions
• •Preventing invalid inheritance structures (for example cycles)
• •Extending template/version services and validation logic

Key Concepts

• •System Template: Root template (isSystem = true, parentTemplateId = null) used as baseline
• •Child Template: Tenant-specific template that references a parent template
• •Inheritance Chain: Ordered parent lineage used to resolve effective conditions
• •Effective Condition Tree: Final merged conditions used when creating a rule version
• •Circular Dependency Guard: Validation preventing template ancestry loops

Guidelines

• •Add parentTemplateId (nullable UUID FK) to the rule template model
• •Add isSystem flag semantics for root/base templates
• •Enforce validation: system templates MUST NOT be children
• •Enforce validation: inheritance graph MUST be acyclic
• •Merge parent and child condition trees deterministically (child extends parent via logical AND unless explicit merge policy is defined)
• •Keep resulting rule versions immutable after creation
• •Surface clear errors for invalid parent references and cycle attempts

Explicitly Forbidden

• •Mutating parent template conditions when customizing child templates
• •Duplicating inherited conditions by copy/paste at controller level
• •Allowing circular parent relationships
• •Evaluating rule versions with unresolved inheritance
• •Hiding inheritance behavior in undocumented implicit transformations

Design Rules

• •Resolve inheritance in application services before persisting a new rule version
• •Keep template metadata and rule version content separate per existing DDD boundaries
• •Ensure merged conditions are auditable and traceable to parent/child sources
• •Parent changes MUST NOT retroactively modify existing immutable rule versions
• •Include organization-aware access controls for parent template usage
• •Index parent foreign key fields for efficient chain resolution

Expected Outcome

After applying this skill:

• •Base/system templates can be reused safely across tenant customizations
• •Child templates produce deterministic merged condition trees
• •Rule version immutability is preserved with inheritance support
• •The template inheritance challenge requirement is fully implemented