Review round 1 of milestone 5: the move settles changed rows under the lock; reports counted by kind; route-proxy at the new SDK; the plan pass never revives an ended assignment; the store's mirror is refused once moved (issues 1090, 1092, 1093)

1090/1092: the move tests pick each report by kind and expect three, all already, on the second run. 1090-1093: under the share lock the switch reads the rows again and writes every key whose value differs from its row (and ends an assignment the store dropped) before recording the kind, so an update the old controller made after the first pass is not lost. 1093: route-proxy is pinned at mesh-sdk f185aedb and vendored; the controller uses only the SDK's asks package. KeepAssignmentPlans decides each key by keepStep, which never makes or revives an assignment. AssignmentsMirrorToWrite refuses once the assignments are moved.

internal/inventory/mirrors.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"time"
 )
@@ -69,6 +70,21 @@ type DeclaredMirrored struct {
 var DeclaredMirroredFields = []string{"kind", "default", "why", "type", "description", "enum", "minimum", "maximum",
 	"pattern", "trusted", "predefined", "required", "runtime"}
 
+// ErrAssignmentsMoved is a write of the store's mirror of the assignments, refused because the assignments are keys of the bus.
+var ErrAssignmentsMoved = errors.New("the assignments are keys of the bus, and the store's rows are no longer what they say")
+
+// AssignmentsMirrorToWrite is AssignmentsMirror for the mirror's writer, which lays what it returns over the bucket and
+// ends the keys it does not return: **refused once the assignments are moved** (ADR 0408 §4), asked at the moment of the
+// write, so a tick that decided before the switch cannot lay mirror-shaped values over the links after it.
+func (i *Inventory) AssignmentsMirrorToWrite(ctx context.Context) (map[string][]byte, error) {
+	if _, on, err := i.ChainReads(ctx, KindAssignments); err != nil {
+		return nil, err
+	} else if on {
+		return nil, ErrAssignmentsMoved
+	}
+	return i.AssignmentsMirror(ctx)
+}
+
 // AssignmentsMirror is every assignment's mirrored value, keyed `<node>.<module>`, with the provisioner's plan of
 // each assignment of a module handed to it, and a value of its own for each module handed to it on a node that
 // nothing assigned there, only pulled in by another (issue 765).