B2h AS17 (2b): the revert ask's words, options and its finding revert-held

RevertAsk asks hold or live, naming the reverted build, the kept data, its
form and the node's words; it expires leaving the newer build running.
RevertHeldFinding is delivery.<node>.<module>.revert-held, a warning that
needs nothing, so the ask is the operator's one message.

Builds: design 47 G §710, §300

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

modules/mesh-delivery-assigner/internal/assign/asks.go

@@ -200,6 +200,54 @@ const (
 	OptionBackupSkip  = mwc.BackupSkip
 )
 
+// The options of the revert ask (design 47 G §710): keep the revert held, or start the reverted build on the live data.
+const (
+	OptionRevertHold = "hold"
+	OptionRevertLive = mwc.RevertLive
+)
+
+// KindRevertHeld is the finding of a held revert (design 47 G §710), scope delivery, id `<node>.<module>`.
+const KindRevertHeld = "revert-held"
+
+// RevertAsk is the ask about a revert of module on node to the build fp that the node holds with no restore point (design 47 G
+// §710, ADR 0539 §16): keep it held, or start the reverted build on the live data as it is. kept names the kept data whose form
+// the revert crosses, form its form, and words are the node's reason in its own words, from its have; asking is the number of
+// the asking, 0 the first, as the backup ask's.
+func RevertAsk(key, node, module, fp, kept, form, words string, asking int, now time.Time) asks.Ask {
+	return assignerAsk(asking, oc.Ask{
+		ID:       meshdeliveryclient.AskingID(key, asking),
+		Headline: fmt.Sprintf("The revert of %s on %s has no restore point", module, node),
+		Explanation: fmt.Sprintf("The revert of %s on %s to %s takes its kept data %s back across form %s, and the node holds it: %s. "+
+			"%s keeps running its newer build until you answer. Started on the live data, the older build reads data written in the newer form.",
+			module, node, short(fp), kept, form, words, module),
+		Options: []oc.Option{
+			{ID: OptionRevertHold, Label: "Keep it held", Does: "the node keeps running the newer build, and the revert waits", Level: occ.Acknowledge},
+			{ID: OptionRevertLive, Label: "Start on the live data", Does: "the node starts the older build on the live data as it is, with nothing restored", Level: occ.Acknowledge},
+		},
+		Who:      occ.Operator,
+		Expires:  occ.FormatTime(now.Add(AskLasts)),
+		OnExpiry: "the module keeps running its newer build",
+		About:    key,
+	})
+}
+
+// RevertAnswerWords are the words a want written again on the operator's answer to the revert ask carries (design 47 G §710).
+func RevertAnswerWords(option string, asking int) string {
+	return fmt.Sprintf("the operator answered %q to the revert ask (asking %d)", option, asking+1)
+}
+
+// RevertHeldFinding is the finding `revert-held` of a revert the node holds with no restore point (design 47 G §710): scope
+// delivery, id `<node>.<module>`, a warning naming the reason, the kept data and its form, and needing nothing, so the
+// operator's one message is the ask.
+func RevertHeldFinding(node, module, kept, form, reason string) Observed {
+	return Observed{Scope: "delivery", ID: node + "." + module, Kind: KindRevertHeld, Machine: node, Severity: "warning",
+		Summary:  fmt.Sprintf("The revert of %s on %s is held: %s (%s, form %s); the ask about it waits for your answer", module, node, reason, kept, form),
+		Headline: fmt.Sprintf("The revert of %s on %s is held", module, node),
+		Explanation: fmt.Sprintf("The node holds the revert of %s: %s (%s, form %s). %s keeps running its newer build until the ask is answered.",
+			module, reason, kept, form, module),
+		Needs: "Nothing for you to do.", Source: "assigner." + KindRevertHeld}
+}
+
 // RecordAsk is the ask about a move of a module of policy record on node to the composition with the digest, judged by the
 // controller to recreate a container, to move data, or not to be judgeable (ADR 0539 §14). The want names the composition only
 // after the answer yes. The way the move was judged is in the ask. asking is the writing's number (AskingSeconds), so a key taken

modules/mesh-delivery-assigner/internal/assign/asks_test.go

@@ -337,7 +337,12 @@ func TestTheRecordAndBackupAsksAreValid(t *testing.T) {
 	}
 	dgst := "sha256:" + strings.Repeat("b", 64)
 	b := BackupAsk(bkey, "ace", "mail", fNew, dgst, "no space left", 0, now)
-	for key, a := range map[string]asks.Ask{rkey: r, bkey: b} {
+	vkey, err := asks.RevertAskKey("ace", "mail", fNew)
+	if err != nil {
+		t.Fatal(err)
+	}
+	v := RevertAsk(vkey, "ace", "mail", fNew, "records", "3", "restore point missing: none of form 3", 0, now)
+	for key, a := range map[string]asks.Ask{rkey: r, bkey: b, vkey: v} {
 		if err := occ.Check(mustAsk(t, a), now); err != nil {
 			t.Errorf("%s: the router refuses the ask: %v", key, err)
 		}
@@ -367,6 +372,22 @@ func TestTheRecordAndBackupAsksAreValid(t *testing.T) {
 	if BackupAnswerWords("again", 0) == BackupAnswerWords("again", 1) {
 		t.Errorf("two answers of the same option are one want value")
 	}
+	// design 47 G §710: the revert ask names the build, the kept data, its form and the node's words, and offers hold and live;
+	// its finding is delivery.<node>.<module>.revert-held, a warning that needs nothing, the ask being the one message.
+	if va := mustAsk(t, v); va.Headline != "The revert of mail on ace has no restore point" || va.Options[0].ID != OptionRevertHold ||
+		va.Options[1].ID != mwc.RevertLive || len(va.Options) != 2 || va.OnExpiry != "the module keeps running its newer build" ||
+		!strings.Contains(va.Explanation, "records") || !strings.Contains(va.Explanation, "form 3") || !strings.Contains(va.Explanation, short(fNew)) ||
+		!strings.Contains(va.Explanation, "Started on the live data, the older build reads data written in the newer form.") {
+		t.Errorf("the revert ask = %+v", va)
+	}
+	if f := RevertHeldFinding("ace", "mail", "records", "3", "restore point missing").Finding(now); views.FindingKey(f.Scope, f.ID, f.Kind) != "delivery.ace.mail.revert-held" ||
+		f.Severity != "warning" || f.Needs != "Nothing for you to do." ||
+		f.Summary != "The revert of mail on ace is held: restore point missing (records, form 3); the ask about it waits for your answer" {
+		t.Errorf("the revert finding = %+v", f)
+	}
+	if RevertAnswerWords(OptionRevertLive, 1) != `the operator answered "live" to the revert ask (asking 2)` {
+		t.Errorf("the words of a live answer: %q", RevertAnswerWords(OptionRevertLive, 1))
+	}
 	c := BackupCondition("ace", "mail", fNew, "no space left", true)
 	if _, err := occ.EncodeCondition(c); err != nil {
 		t.Errorf("the backup condition is refused: %v", err)