Repository metrics observability

repository-metrics/v1 is informational evidence about repository size, coupling and dependency structure. It does not change findings, Health, metric budgets or the process exit code. For enforcing budgets, use declared architecture metrics.

Get the evidence

Use the Health/review workflow to obtain Health and architecture-change artifacts. The PR report includes a compatible base/current metrics delta. A validation artifact may also carry repository metrics, but source-size data can be partial when that analysis did not need the lazy source inventory.

The metrics badge command reads a supported artifact containing the metrics, not an already-rendered Shields payload:

mkdir -p artifacts/metrics-badges
arch-linter-net badge repository-metrics --input artifacts/health.json \
  --output-directory artifacts/metrics-badges

--output-directory writes repository-metrics-badge.json, repository.json and structure.json. For just one Source lines file, use --output instead, not together with --output-directory.

Check badge repository-metrics --help in the pinned package before adopting this command; older packages may not contain it. Inspect availability and reason codes in the source artifact before interpreting a number. Missing old-version metrics are unavailable, not zero. Do not run every metric separately.

Absolute metrics

The size group includes physical C# source lines, readable source files, discovered projects, reflected types and public types. Physical source lines are not a promise of Visual Studio logical SLOC equivalence. Existing generated- file exclusions and project ownership apply; overlapping roots do not count a file twice.

The coupling group contains deduplicated internal project-reference edges, dependencies per project, directed density, maximum fan-in/fan-out and per-project rows. Afferent coupling (Ca) is fan-in; efferent coupling (Ce) is fan-out. Instability is Ce / (Ca + Ce), defined as zero when there are no incident edges.

For more than one project, density is non-self-loop directed edges divided by projects * (projects - 1); otherwise it is zero. DependencyCount still includes self-loops. This keeps density bounded without hiding cycle evidence.

The structure group includes dependency depth, strongly connected components (SCCs), largest SCC size/ratio and projects participating in cycles. Self-loops are cycles. Depth counts the longest directed path in the condensation graph, with cycles collapsed before counting edges.

Availability and change reports

Complete evidence requires a complete type universe, source inventory and project graph. Partial evidence retains safely measured values and reasons for missing/ambiguous inputs. Unavailable values are null, not zero.

Architecture-change artifacts carry compatible base-to-head deltas. Missing or incompatible base evidence makes that delta unavailable. report pr renders it in the existing bounded report, not another comment or a new governance decision.

Badge provenance

Source lines and optional grouped Repository/Structure badges are absolute snapshots, not PR deltas or quality grades. Health uses its own separate badge. The upstream repository publishes metrics beside Health on its existing raw badge branch, using verified producer artifacts. That is a repository-specific publication example, not a requirement to create a new publisher in every consumer.

Do not feed the raw branch's rendered architecture-health.json Shields file back into the metrics command as though it were a full Health document. A stable filename is not a schema identity.

Performance boundary

Calculation is cached in the immutable analysis session and reuses its type index, source facts and project graph. It does not add another MSBuild load, semantic compilation or traversal per metric. A report/Health caller can request source inventory; a lighter validation may leave source-size data partial.

Legacy cache entries may lack repository metrics. They retain the old artifact rather than fabricate numbers; an eligible fresh analysis produces current metrics. Enabling these informational views does not establish that a real project is cache-eligible or that every workflow will obtain a speedup.