Module ladder 

The ladder: where a unit of work came from. One provenance record per subject, written once. This build knows the variants a bug writes; later rungs add theirs as variants.

Enums

Origin

Where a unit or a requirement came from.

Rung

The rung a unit stands on: a quick change (L1), a bug (L2) or a feature. A quick-change or bug unit’s pipeline authors and confirms its own acceptance, so the review writes no tests for it.

Functions

rung_of

The rung of unit, from the standing units the format names for the project ((unit, rung)): a standing unit, or a unit under one (<standing>/<slug>), is on its rung; every other unit is a feature.

subject

The subject a bug’s origin is recorded for: <unit>/<requirement>.