Keep nothing of a restricted message past its stream's age, only count it (issue 728)

A record kept without its body still carried its subject, which names whose mail it was, with no age. The lead decided such a message is not kept at all: the notice is taken, the message counted, and the log and an aged-out condition say how many messages of the stream aged out undelivered. Unrestricted streams are unchanged.

cmd/mesh-controller/deadletters_aging_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"strings"
 	"testing"
 	"time"
 
@@ -67,3 +68,31 @@ func TestADeadLetterThatAgesOutClearsItsConditionAndSaysSo(t *testing.T) {
 		t.Fatalf("not plain: %s", why)
 	}
 }
+
+// **A message past its restricted stream's age is not kept, only counted** (novox/hq ADR 0376, as the feature's lead
+// decided): its advisory is said as a condition whose words give how many aged out undelivered and from which stream.
+func TestMessagesNotKeptPastTheirAgeAreCounted(t *testing.T) {
+	now := time.Date(2026, 10, 15, 12, 0, 0, 0, time.UTC)
+	f := calm(now)
+	f.advisories = []link.Advisory{{Kind: link.AdvisoryMaxDeliveries, ID: "MAIL.ace_mailer", Stream: "MAIL",
+		Consumer: "ace_mailer", Token: link.AdvisoryAgedOut, Said: "the consumer gave up after the stream's age",
+		First: now.Add(-10 * time.Minute), Last: now.Add(-time.Minute), Count: 2}}
+	var found []conditions.Observation
+	for _, o := range watchAdvisories(f) {
+		if o.Token == link.AdvisoryAgedOut {
+			found = append(found, o)
+		}
+	}
+	if len(found) != 1 {
+		t.Fatalf("said %+v", found)
+	}
+	o := found[0]
+	if o.Headline != "2 messages of the stream MAIL aged out undelivered" || o.Times != 2 ||
+		!strings.Contains(o.Summary, "2 messages of the stream MAIL aged out undelivered") {
+		t.Fatalf("%+v", o)
+	}
+	if why, ok := conditions.PlainWords(conditions.Words{Headline: o.Headline, Explanation: o.Explanation,
+		Resolved: o.Resolved, Needs: o.Needs}); !ok {
+		t.Fatalf("not plain: %s", why)
+	}
+}

cmd/mesh-controller/signals.go

@@ -584,6 +584,18 @@ func watchAdvisories(f *signalFacts) []conditions.Observation {
 				"for you yet. It tries again every minute."
 			o.Resolved = "Resolved: the message is kept"
 		}
+		if a.Kind == link.AdvisoryMaxDeliveries && a.Token == link.AdvisoryAgedOut {
+			// Given up on after its restricted stream's age, so not kept at all, only counted (novox/hq ADR 0376).
+			counted := link.AgedOutWords(a.Count, a.Stream)
+			o.Machine = consumerMachine(a.Stream, a.Consumer)
+			o.Summary = fmt.Sprintf("%s in the last hour: %s", counted, a.Said)
+			o.Headline = clip(conditions.Capital(counted), 60)
+			o.Explanation = conditions.Capital(fmt.Sprintf("%s could not handle %s, and by the time it gave up the "+
+				"stream's time limit had passed, so the mesh did not keep them. Nothing to do; this clears an hour "+
+				"after the last one.", consumerWho(a.Stream, a.Consumer), map[bool]string{true: "some messages",
+				false: "a message"}[a.Count > 1]))
+			o.Resolved = "Resolved: no more messages of the stream " + a.Stream + " aged out undelivered"
+		}
 		out = append(out, o)
 	}
 	if f.busFaultsErr != nil {