How CockroachDB, Prometheus, Ecto, and Oban handle the
things that touch everything but belong nowhere. Includes
red flags and review questions for each concern.
Not just per-file patterns — structural analysis of how these
codebases organize at scale. Key findings:
- 116 packages @ 4 files each (CockroachDB)
- Interface layer breaks circular deps
- Testability designed in, not bolted on
- Composition via data, not inheritance
Rodin