refactor(metrics): make PrometheusObserver inherit SpecObserver protocol#976
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tcoratger merged 1 commit intoJun 12, 2026
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Inheriting the protocol turns conformance into a type-checked contract. The type checker now verifies every protocol member is implemented, instead of relying on implicit structural typing. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Summary
The Prometheus-backed observer matched the spec observer protocol only by structural typing, so a drift between the two (a renamed or removed hook) would go unnoticed until runtime.
This makes the class explicitly inherit the protocol, turning conformance into a type-checked contract: the type checker now verifies every protocol member is implemented.
Changes
PrometheusObservernow inheritsSpecObserver.All three protocol members were already implemented, so no behavior changes.
Verification
uv run pytest tests/node/metrics/test_spec_observer.py— 9 passed.just check— ruff, ruff format, ty (validates protocol conformance), codespell, mdformat all pass.🤖 Generated with Claude Code