Keep assignments in the assignments bucket and move the rows there at start (issue 1093)

Once chain_moved records the kind, Assign, Unassign and Assigned write and read the keys <node>.<module>, and every join of the store that read assignments is made from the bucket: where a module runs, what is behind, what a machine awaits, a given value due for replacement, taking a module, and whether a module may be forgotten (refused while a standing assignment names it). An unassignment ends the key with a marker and keeps its earlier values, as it removed the row; no ended or pending mark is written yet. The generation rises with each change, and a seat held by an assignment goes with it: the foreign key from seat_holding is dropped by migration 0104 and the controller says both. The provisioner's plan is kept in the values by a pass of the tick that writes that one field by compare-and-set; the assignment-changed event is said from what the bucket holds, whoever wrote it. The start moves the rows with what each machine was last sent, keeping a plan the mirror put in a value.

internal/inventory/given.go

@@ -93,11 +93,28 @@ func (i *Inventory) ReplaceGivenAfterStart(ctx context.Context, node, declared s
 	if declared == "" {
 		return nil, nil
 	}
+	// Only a module assigned there: from the bucket when the assignments are on the bus, else the store's join.
+	_, onTheBus, err := i.ChainReads(ctx, KindAssignments)
+	if err != nil {
+		return nil, err
+	}
+	assignedHere := map[string]bool{}
+	join := `join assignment a on a.node = s.node and a.module = s.module`
+	if onTheBus {
+		join = ``
+		modules, err := i.assignedModules(ctx, node)
+		if err != nil {
+			return nil, err
+		}
+		for _, m := range modules {
+			assignedHere[m] = true
+		}
+	}
 	rows, err := i.store.Pool().Query(ctx,
 		`select s.node, s.module, s.name, s.replace_after_start
 		   from module_secret s
 		   join node n on n.id = s.node
-		   join assignment a on a.node = s.node and a.module = s.module
+		   `+join+`
 		  where n.name = $1 and n.sent = $2 and n.sent_at > s.replace_after_start
 		    and s.origin = 'accepted' and s.replace_after_start is not null
 		    and (not n.adopted or exists (select 1 from taken t where t.node = s.node and t.module = s.module))
@@ -117,6 +134,9 @@ func (i *Inventory) ReplaceGivenAfterStart(ctx context.Context, node, declared s
 			rows.Close()
 			return nil, err
 		}
+		if onTheBus && !assignedHere[d.module] {
+			continue
+		}
 		dues = append(dues, d)
 	}
 	rows.Close()