Forge bridge: write a head pushed to a pull request into another base as closed, and say so (issue 1422)

The checker judges pull requests into main only and source.main names main's head only (ADR 0484 §11), but a live update
into another base (de-spiegel#6 into nox-mesh) became a candidate, unlike at the start (OpenPulls) and at its merge. Once
the gate seeds a repository's trunk head, such a candidate would be judged against main's head: a verdict that lies.

modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main.go

@@ -96,6 +96,9 @@ func handle(ctx context.Context, m delivered, pub publisher, trees bridge.Trees,
 		logger.Printf("%s: %s could not be written on FORGE, left for redelivery: %v", m.Subject(), msg.Event, err)
 		return
 	}
+	if msg.Said != "" {
+		logger.Printf("%s: %s", m.Subject(), msg.Said)
+	}
 	_ = m.Ack()
 }
 

modules/mesh-delivery-forge-bridge/internal/bridge/bridge.go

@@ -54,6 +54,8 @@ var LockFiles = []string{"go.sum", "package-lock.json"}
 type Message struct {
 	Event string
 	Data  []byte
+	// Said is what the bridge did that the log says, beside writing the message; empty for none.
+	Said string
 }
 
 // The subjects of the forge module's events the bridge writes pull messages for (mesh-catalog modules/gitea,
@@ -148,6 +150,15 @@ func ConvertWith(subject string, data []byte, trees Trees, files Files, list Lis
 	if subject == MergedSubject && p.Base == Trunk {
 		return merged(subject, p, trees, files, list)
 	}
+	said := ""
+	if action == delivery.PullUpdated && p.Base != "" && p.Base != Trunk {
+		// The checker judges pull requests into main only, and source.main names main's head only (novox/hq ADR 0484 §11): a
+		// pull request into another base is no candidate, as it is none at the start (OpenPulls) and at its merge. It is
+		// written closed, so a candidate an older head made is taken out, and said (issue 1422).
+		action = delivery.PullClosed
+		said = fmt.Sprintf("%s/%s#%d at %s is into %s, not %s: written closed, so it is no candidate; the checker judges pull requests into %s only (novox/hq ADR 0484 §11)",
+			p.Owner, p.Repo, p.Number, p.HeadSHA[:12], p.Base, Trunk, Trunk)
+	}
 	f := delivery.Forge{Kind: delivery.ForgePull, Repository: p.Owner + "/" + p.Repo, Branch: p.Head, Number: p.Number,
 		Head: p.HeadSHA, Action: action}
 	// The directories are the forge's word only when it said it could read them (module_dirs_said).
@@ -173,7 +184,7 @@ func ConvertWith(subject string, data []byte, trees Trees, files Files, list Lis
 	if err != nil {
 		return Message{}, unreadable(subject, "%v", err)
 	}
-	return Message{Event: event, Data: body}, nil
+	return Message{Event: event, Data: body, Said: said}, nil
 }
 
 // MaxReadsInFlight is how many files of the forge inputsOf asks for at once. A merge into a repository of many

modules/mesh-delivery-forge-bridge/internal/bridge/bridge_test.go

@@ -110,6 +110,21 @@ func TestClosedBecomesAClosedPullMessage(t *testing.T) { // 1235/AC4
 	if !delivery.SameForge(f, want) {
 		t.Errorf("message = %+v, want %+v", f, want)
 	}
+	// Issue 1422, ADR 0484 §11: a head pushed to a pull request into another base is written closed, read nothing for, and said;
+	// one into main is no closed message, and an event naming no base is written as before.
+	msg, err = Convert(updatedSubject, updated(map[string]any{"base": "nox-mesh"}), nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if f, err = delivery.DecodeForge(msg.Data); err != nil || !delivery.SameForge(f, want) || !strings.Contains(msg.Said, "is into nox-mesh, not main") {
+		t.Errorf("an update into nox-mesh is %+v (%v), said %q; want it closed and said", f, err, msg.Said)
+	}
+	for _, base := range []any{"main", nil} {
+		msg, err = Convert(updatedSubject, updated(map[string]any{"base": base}), nil, anyFiles)
+		if f, _ = delivery.DecodeForge(msg.Data); err != nil || f.Action != delivery.PullUpdated || msg.Said != "" {
+			t.Errorf("an update with base %v is %+v (%v), said %q; want it updated", base, f, err, msg.Said)
+		}
+	}
 }
 
 func TestUnreadableEventsWriteNothing(t *testing.T) { // 1235/AC5