Drop the plan state from the store and the assignments: migration 0108 and placement-only assignments (release 6, issue 1945 B9, B4)

internal/inventory/collection.go

@@ -458,7 +458,7 @@ func keptLately(builds []Build, planned map[string]bool, now time.Time, within t
 	return out
 }
 
-// keptLatelyOrPlanned is keptLately of every build the records hold, against the plans that have not ended.
+// keptLatelyOrPlanned is keptLately of every build the records hold, (no plan names a build any more, ADR 0539 §17).
 func (i *Inventory) keptLatelyOrPlanned(ctx context.Context) (map[string][]string, error) {
 	c, err := i.theChain(ctx)
 	if err != nil {
@@ -468,27 +468,7 @@ func (i *Inventory) keptLatelyOrPlanned(ctx context.Context) (map[string][]strin
 	if err != nil {
 		return nil, err
 	}
-	plans, err := i.OpenPlans(ctx)
-	if err != nil {
-		return nil, err
-	}
-	return keptLately(all, plannedBuilds(plans), time.Now().UTC(), i.lately()), nil
-}
-
-// plannedBuilds is every build id these plans name: a module's build, and the builds a rollout carried.
-func plannedBuilds(plans []Plan) map[string]bool {
-	out := map[string]bool{}
-	for _, p := range plans {
-		for _, m := range p.Modules {
-			if m != nil && m.Build != "" {
-				out[m.Build] = true
-			}
-		}
-		for _, id := range p.Builds {
-			out[id] = true
-		}
-	}
-	return out
+	return keptLately(all, nil, time.Now().UTC(), i.lately()), nil
 }
 
 // digestIn is the `sha256:<hex>` a reference names, empty when it names none.