Evolution without fragmentation tutorial

This tutorial shows what happens after deployment. You will follow drift, duplicated behavior, version sprawl, and runtime-governed recovery without pretending every system can be rewritten.

By Enrico Piovesan Updated June 22, 2026

Tutorial route

Use the links here to move between the evolution chapters without burying the learning path in the footer.

Open source folder All UMA examples Previous: Architectural Tradeoffs Next: Discoverable Decisions

What you will learn

how locally valid changes create fragmentation over time
why versioning needs explicit coexistence rules
how runtime governance supports brownfield adoption

Prerequisites

Rust 1.76 or newer
Node.js 20 or newer
a checkout of the repository

Full tutorial

Enter the example

cd chapter-11-evolution-without-fragmentation

List the evolution labs
```
./scripts/list_labs.sh
```

Validate the contract anchor

./scripts/validate_evolution.sh lab1-contract-anchor

Run the coherent baseline

./scripts/run_evolution_demo.sh lab1-contract-anchor

Inspect behavioral drift

./scripts/diff_evolution.sh lab1-contract-anchor lab2-behavioral-drift

Run duplicate implementations

./scripts/run_evolution_demo.sh lab3-duplicate-implementations

Run governed coexistence

./scripts/run_evolution_demo.sh lab5-runtime-governed-coexistence

Run the full smoke path
```
./scripts/smoke_evolution_labs.sh
```

What to inspect

After each command, look for these proof points. They are the signals that connect the code example back to the UMA architecture claim.

Verdict
behavioral_drift
duplicate_behavior
version_fragmentation
Runtime Decisions

Acceptance check

The chapter-level validation path is:

./scripts/smoke_evolution_labs.sh

Return to the repository root for the final acceptance gate:

cd ..
./scripts/smoke_reader_paths.sh

Where to go next

Chapter 12 turns runtime decisions into discoverable artifacts.

Open source folder All UMA examples Read Chapter 12: Evolving Systems → Previous: Architectural Tradeoffs Next: Discoverable Decisions