Show in a proposal's brief what stays held as each node holds it today (issue 1126)

go/compose/judge/judge.go

@@ -209,7 +209,7 @@ func JudgeAnswers(p delivery.PlacementProposal, intended map[string]map[string]b
 }
 
 // Brief is the verdict as the ask's brief shows it, by node (§5): what the proposal changes and what each node answered
-// beside it, marked, with the proposal's why.
+// beside it, marked, and what stays held as the node holds it today, with the proposal's why.
 func Brief(p delivery.PlacementProposal, v delivery.PlacementVerdict) string {
 	var b strings.Builder
 	fmt.Fprintf(&b, "%s (proposed by %s)", p.Why, p.By)
@@ -223,6 +223,11 @@ func Brief(p delivery.PlacementProposal, v delivery.PlacementVerdict) string {
 	for _, n := range p.Nodes() {
 		nodes[n] = true
 	}
+	for n, a := range v.Answers {
+		if len(a.Held) > 0 {
+			nodes[n] = true
+		}
+	}
 	names := make([]string, 0, len(nodes))
 	for n := range nodes {
 		names = append(names, n)
@@ -238,6 +243,13 @@ func Brief(p delivery.PlacementProposal, v delivery.PlacementVerdict) string {
 		if m := v.Unintended[n]; len(m) > 0 {
 			fmt.Fprintf(&b, "; also differs, not computed: %s", strings.Join(m, ", "))
 		}
+		if held := v.Answers[n].Held; len(held) > 0 {
+			var names []string
+			for _, h := range held {
+				names = append(names, h.Module)
+			}
+			fmt.Fprintf(&b, "; stays held as today: %s", strings.Join(names, ", "))
+		}
 	}
 	return b.String()
 }

go/compose/judge/judge_test.go

@@ -52,6 +52,8 @@ func TestJudge(t *testing.T) {
 			Refusals: []delivery.ModuleRefused{{Module: "web", Why: "no own secret"}}}}, nil, delivery.VerdictFail, "laptop refuses", ""},
 		{"a node not answering, within its bound", false, map[string]*delivery.CandidateAnswer{"anchor": same(7)}, map[string]bool{"laptop": true}, delivery.VerdictWaits, "laptop (offline)", ""},
 		{"an answer of an earlier revision, past its bound", false, map[string]*delivery.CandidateAnswer{"anchor": same(6), "laptop": same(8)}, nil, delivery.VerdictFail, "anchor did not answer", ""},
+		{"a module held as today passes, shown in the brief", false, map[string]*delivery.CandidateAnswer{"anchor": same(7), "laptop": {Proposal: "p-one", Revision: 8,
+			Verdict: delivery.CandidateSame, Held: []delivery.ModuleRefused{{Module: "spiegel", Why: "a required value is unset"}}}}, nil, delivery.VerdictPass, "", ""},
 		{"its later answer", false, map[string]*delivery.CandidateAnswer{"anchor": same(7), "laptop": same(8)}, nil, delivery.VerdictPass, "", ""},
 	} {
 		q := p
@@ -61,6 +63,9 @@ func TestJudge(t *testing.T) {
 		if v.State != row.state || !strings.Contains(all, row.words) {
 			t.Errorf("%s: %s, %q", row.name, v.State, all)
 		}
+		if strings.HasPrefix(row.name, "a module held as today") && !strings.Contains(Brief(q, v), "stays held as today: spiegel") {
+			t.Errorf("%s: the brief does not show it: %s", row.name, Brief(q, v))
+		}
 		if row.marked != "" && (!slices.Contains(v.Unintended["anchor"], row.marked) || !strings.Contains(Brief(q, v), "not computed: "+row.marked)) {
 			t.Errorf("%s: the difference is not marked: %+v, %s", row.name, v.Unintended, Brief(q, v))
 		}