Singleton Pattern / Dependency Injection
Kind: tension
Record: tension:dependency-injection-singleton-pattern
Canonical: Schema
"singleton-pattern" (design-patterns-core layer) is traded against "Dependency Injection" (extensibility-core layer) — a principle cannot be scope-separated from a quality, metric, or cost it competes with; resolve by measuring "Dependency Injection" and choosing an explicit operating point.
Listed in Tensions, after Singleton Pattern / Testability and before Adapter Pattern / Mapping Overhead.