I. Immutable Logic

The Requirement

Code and its dependencies must be versioned as an atomic unit.

The Problem

In the traditional model, application code is treated as the only deliverable that matters. Business logic, revenue generation, and value creation all happen here. Teams obsess over code quality, test coverage, and clean architecture.

But code alone is just text. If your code is not running, it is not producing value.

The Practice

A hermetic asset versions all application logic together:

• Source code in version control
• Dependency manifests with locked versions (package-lock.json, go.sum, requirements.txt)
• Build artifacts tied to specific commits
• No floating versions, no implicit dependencies

Every change produces a new immutable version. New module? New version. Hotfix? New version. The version identifier is a complete snapshot of the application’s logic at that point in time.

The Litmus Test

Can you checkout any historical version and build it deterministically? If dependency resolution can produce different results today than it did six months ago, your logic is not immutable.

What This Enables

When application logic is truly immutable, you gain the ability to reason about your system. Version 1.4.2 means exactly one thing, forever. Debugging production issues is manageable because you always know what you’re deploying.