maintainability-flexibility-extensibility-guardrails

name	maintainability-flexibility-extensibility-guardrails
description	Guardrails for maintainable, flexible, and extendable code in Zentro (Go + Wails + React).

Skill 16: Maintainability, Flexibility, Extensibility Guardrails

Purpose

Keep code easy to understand, safe to change, and practical to extend.

Core Outcomes

Improve at least 3 of 5 outcomes in non-trivial changes:

• Clarity
• Change isolation
• Replaceability
• Testability
• Operability

Decision Framework

1. Define boundary.

• What behavior changes?
• Which module owns it?
• Which modules should stay unaware?

2. Identify variation.

• What may change in 1-3 months?
• Which provider/platform differences matter?
• What is stable vs volatile?

3. Choose smallest useful abstraction.

• Keep concrete code for one-off flows.
• Add interface only for real variability or test seams.
• Keep interfaces owned by consumers.

4. Protect contracts.

• Preserve public behavior unless intentionally changed.
• Validate boundary inputs.
• Return contextual errors.

5. Verify quality.

• Add/update targeted tests.
• Add regression tests for bug fixes.
• Run focused checks first.

Mandatory Rules

• Keep Wails-exposed methods thin.
• Backend services should not leak DB-driver details to frontend.
• Frontend business logic lives in features/services/stores.
• Avoid hidden global mutable state.
• Avoid speculative abstraction without volatility evidence.