Merge pull request 'Rename node-hosts-file to node-hostname, and refuse one seat claimed under two names (hq ADR 0223 part 3)' (#69) from hostname-module into main

internal/catalogue/resolve.go

@@ -816,13 +816,17 @@ func checkClaims(modules []Manifest, node Node, elsewhere []Held, holdings []Hel
 			if byScope[scope] == nil {
 				byScope[scope] = map[string]string{}
 			}
-			if other, taken := byScope[scope][c.Name]; taken {
+			// **One seat under either of its names** (novox/hq ADR 0122): a manifest registered before
+			// a rename claims the former name, and one written after it the current — two claimants of
+			// one seat, compared by the seat they resolve to and not by how each spelled it.
+			seat := canonicalSeat(c.Name)
+			if other, taken := byScope[scope][seat]; taken {
 				problems = append(problems, fmt.Sprintf(
 					"%s and %s both claim %q, and only one thing may hold it per %s",
-					other, m.Module, c.Name, scope))
+					other, m.Module, seat, scope))
 				continue
 			}
-			byScope[scope][c.Name] = m.Module
+			byScope[scope][seat] = m.Module
 			held = append(held, Held{Claim: c.Name, Scope: scope, Node: node.Name,
 				Module: m.Module, Site: node.Site})
 		}
@@ -831,7 +835,7 @@ func checkClaims(modules []Manifest, node Node, elsewhere []Held, holdings []Hel
 	// And against the rest of the mesh, for the scopes that reach past this machine.
 	for _, h := range held {
 		for _, e := range elsewhere {
-			if e.Node == node.Name || e.Claim != h.Claim || e.Scope != h.Scope {
+			if e.Node == node.Name || canonicalSeat(e.Claim) != canonicalSeat(h.Claim) || e.Scope != h.Scope {
 				continue
 			}
 			switch h.Scope {
@@ -862,6 +866,15 @@ func checkClaims(modules []Manifest, node Node, elsewhere []Held, holdings []Hel
 	return held, problems
 }
 
+// canonicalSeat is the seat a claimed name refers to, by its current name: itself for a name the mesh
+// does not know (a module's own seat), its seat's name for a former one.
+func canonicalSeat(name string) string {
+	if s, known := SeatNamed(name); known {
+		return s.Name
+	}
+	return name
+}
+
 // checkResources refuses two modules writing the same thing.
 //
 // This costs no manifest field: the mesh already holds every resource of every module, so two