mesh-issues: an issue knows whether its fix is delivered, says it ready to verify, and a fix stuck after its merge is said (hq ADR 0281)

The operator approved measuring from the delivery's own events whether each fix an
issue names reached the machines; delivered is not resolved, and a merged fix that
does not arrive is said on the issue and the operator's channel instead of found.

modules/mesh-issues/cmd/mesh-issues/tracker.go

@@ -30,9 +30,11 @@ type Tracker struct {
 	Records Records
 	// Judge is the triage's way to a model (ADR 0278, ADR 0279); nil judges nothing.
 	Judge Judgement
-	// Deliveries answers a pull request's delivery state (ADR 0279 §3); nil asks nothing.
+	// Deliveries answers a pull request's delivery (ADR 0279 §3, ADR 0281); nil asks nothing.
 	Deliveries DeliveryState
-	groom      grooming
+	// Notify tells the operator's channel of a stuck fix (ADR 0281); nil says nothing there.
+	Notify Notifier
+	groom  grooming
 }
 
 // The events this module says, one per kind of change.
@@ -395,12 +397,14 @@ func (t *Tracker) move(by string, a MoveAsk) (*Moved, error) {
 	is, err := t.change(a.Number, func(is *Issue) error {
 		changed = nil
 		from = is.Status
-		if from == to {
-			return fmt.Errorf("issue %d is already %s", is.Number, to)
-		}
+		// A field counts as changed only when its value does, so a move that changes nothing is refused.
 		set := func(name string, cond bool, apply func()) {
-			if cond {
-				apply()
+			if !cond {
+				return
+			}
+			before, _ := json.Marshal(is)
+			apply()
+			if after, _ := json.Marshal(is); string(before) != string(after) {
 				changed = append(changed, name)
 			}
 		}
@@ -410,14 +414,19 @@ func (t *Tracker) move(by string, a MoveAsk) (*Moved, error) {
 		set("replay", replay != "", func() { is.Replay, is.ReplayNone = replay, "" })
 		set("replay-none", replayNone != "", func() { is.ReplayNone, is.Replay = replayNone, "" })
 		set("reason", reason != "", func() { is.Reason = reason })
+		// The same status again only to change what it holds: a fix named while the issue stays located, to be
+		// resolved once it is delivered and proven (ADR 0281 §3).
+		if from == to && len(changed) == 0 {
+			return fmt.Errorf("issue %d is already %s", is.Number, to)
+		}
 		if err := cycleRules(is, to); err != nil {
 			return err
 		}
 		is.Status = to
-		if to == StatusResolved || to == StatusWontfix {
+		if (to == StatusResolved || to == StatusWontfix) && from != to {
 			at := t.now()
 			is.Closed = &at
-		} else {
+		} else if to != StatusResolved && to != StatusWontfix {
 			is.Closed = nil
 		}
 		return nil
@@ -622,6 +631,8 @@ type Row struct {
 	Ready    bool   `json:"ready"`
 	// SuggestedOwner is the triage's or a person's suggestion, for an issue located nowhere yet.
 	SuggestedOwner string `json:"suggested-owner,omitempty"`
+	// Delivery is whether its fix is delivered, in words (ADR 0281); empty when fixed-by names no pull request.
+	Delivery string `json:"delivery,omitempty"`
 }
 
 // Listed is the answer to a list.
@@ -700,7 +711,7 @@ func (t *Tracker) List(a ListAsk) (*Listed, error) {
 		out.Matched++
 		if len(out.Rows) < limit {
 			out.Rows = append(out.Rows, Row{Number: n, Status: is.Status, Owner: strings.Join(is.LocatedIn, "; "), Title: is.Title,
-				Severity: is.Severity, Needs: is.Needs, Ready: ready, SuggestedOwner: is.SuggestedOwner})
+				Severity: is.Severity, Needs: is.Needs, Ready: ready, SuggestedOwner: is.SuggestedOwner, Delivery: DeliveryLine(is)})
 		}
 	}
 	switch {