Lock File
Domain: Package Ecosystem
🎯 Motivation
A lock file records the exact resolved versions of every dependency, including transitive ones. It guarantees bit-for-bit reproducible environments across different machines and time.
📋 Concrete Example
uv.lock or poetry.lock pins not just requests==2.31.0 but also urllib3==2.0.4 and certifi==2023.7.22 — the full resolved tree. Committing the lock file makes CI use identical versions.
🔗 Analogy
A photo of your completed Lego model records every brick and color. Another person with the same photo and the same brick set can rebuild it exactly. Without the photo, they might use different bricks.