An older merge does not move a source

The forge announces what it finds merged, and an old merge surfacing late moved the recorded head
backwards and rebuilt everything built from that repository, once per old merge. A merge made
before the source was last seen is history; one that says nothing about when is taken as news.
The catalogue now carries when each source was last seen. The bus-records test follows #116:
a module's tools are every one under its own name.

cmd/mesh-controller/order_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/novox/mesh-controller/internal/catalogue"
 	"github.com/novox/mesh-controller/internal/inventory"
@@ -90,3 +91,18 @@ func TestAMergeMatchesTheSourcesBuiltFromIt(t *testing.T) {
 		}
 	}
 }
+
+// A merge made before the source was last seen is history: it does not move the source, and a
+// merge that says nothing about when it was made is taken as news.
+func TestAMergeOlderThanTheLastLookIsHistory(t *testing.T) {
+	seen := time.Date(2026, 9, 28, 3, 0, 0, 0, time.UTC)
+	if !isHistory("2026-09-28T02:00:00Z", seen) {
+		t.Fatal("an older merge was taken as news")
+	}
+	if isHistory("2026-09-28T04:00:00Z", seen) {
+		t.Fatal("a newer merge was taken as history")
+	}
+	if isHistory("", seen) || isHistory("2026-09-28T02:00:00Z", time.Time{}) {
+		t.Fatal("a merge or a source with no time on it was refused")
+	}
+}

cmd/mesh-controller/upgrades.go

@@ -240,6 +240,13 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 		if e.Source.BuiltFrom == m.Commit {
 			continue
 		}
+		// **A merge older than the last look at the source is history, not a move.** The forge
+		// announces what it finds merged, and an old merge surfacing late would otherwise move the
+		// recorded head backwards and rebuild everything built from that repository, once per old
+		// merge (2026-09-28).
+		if isHistory(m.MergedAt, e.Source.Seen) {
+			continue
+		}
 		if err := inv.SourceMoved(ctx, e.Manifest.Module, m.Commit); err != nil {
 			return notNow(err)
 		}
@@ -362,3 +369,16 @@ func standsOnModule(e inventory.Entry, module string, against map[string][]strin
 	}
 	return false
 }
+
+// isHistory is whether a merge made at mergedAt predates the last time the source was seen. A merge
+// with no time on it is taken as news: refusing it would silence a forge that says less.
+func isHistory(mergedAt string, seen time.Time) bool {
+	if mergedAt == "" || seen.IsZero() {
+		return false
+	}
+	at, err := time.Parse(time.RFC3339, mergedAt)
+	if err != nil {
+		return false
+	}
+	return at.Before(seen)
+}

internal/inventory/busrecords_test.go

@@ -86,9 +86,11 @@ func TestAnAssignedModuleBecomesAUserWithWhatItDeclared(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		// Its tools are every one under its own name — the list in the manifest is a person's
+		// vocabulary for asking, not the module's permission to answer.
 		if !granted(perms.Publish, "mesh.mod.shop.event.order.placed") ||
 			!granted(perms.Publish, "mesh.seat.telegram-sender.accept.send") ||
-			!granted(perms.Subscribe, "mesh.mod.shop.tool.price") {
+			!granted(perms.Subscribe, "mesh.mod.shop.tool.>") {
 			t.Fatalf("one.shop's authority is not what it declared: %+v", perms)
 		}
 	}

internal/inventory/catalogue.go

@@ -8,6 +8,7 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/jackc/pgx/v5"
 	"github.com/novox/mesh-controller/internal/catalogue"
@@ -38,6 +39,9 @@ type Source struct {
 	BuiltFrom string
 	// Head is the newest commit the source is known to have.
 	Head string
+	// Seen is when the source was last looked at — by a build, by hand, or by the forge saying it
+	// moved. What a late report of an older move is judged against.
+	Seen time.Time
 }
 
 // Current reports whether what the mesh holds is what the source last had.
@@ -936,12 +940,13 @@ func (i *Inventory) Catalogued(ctx context.Context) ([]Entry, error) {
 		`select m.name, m.manifest,
 		        coalesce(m.source, ''), m.source_path, m.source_seat, coalesce(m.ref, ''),
 		        coalesce(m.built_from, ''), coalesce(m.source_head, ''),
+		        coalesce(m.source_seen, to_timestamp(0)),
 		        coalesce(array_agg(n.name order by n.name) filter (where n.name is not null), '{}')
 		 from module m
 		 left join assignment a on a.module = m.name
 		 left join node n on n.id = a.node
 		 group by m.name, m.manifest, m.source, m.source_path, m.source_seat, m.ref, m.built_from,
-		          m.source_head
+		          m.source_head, m.source_seen
 		 order by m.name`)
 	if err != nil {
 		return nil, err
@@ -955,9 +960,12 @@ func (i *Inventory) Catalogued(ctx context.Context) ([]Entry, error) {
 		var source Source
 		var on []string
 		if err := rows.Scan(&name, &raw, &source.Repository, &source.Path, &source.Seat, &source.Ref,
-			&source.BuiltFrom, &source.Head, &on); err != nil {
+			&source.BuiltFrom, &source.Head, &source.Seen, &on); err != nil {
 			return nil, err
 		}
+		if source.Seen.Unix() == 0 {
+			source.Seen = time.Time{}
+		}
 		var m catalogue.Manifest
 		if err := json.Unmarshal(raw, &m); err != nil {
 			return nil, err

internal/link/events.go

@@ -128,6 +128,8 @@ type SourceMoved struct {
 	Commit   string `json:"merge_commit_sha"`
 	CloneURL string `json:"clone_url"`
 	HTMLURL  string `json:"html_url"`
+	// MergedAt is when the forge merged it, RFC 3339. What decides whether this is news.
+	MergedAt string `json:"merged_at"`
 }
 
 type Upgraded struct {