The gate's module check notes a seat another module declares, which it was not given (hq issue 364)

The gate passes only the manifests a change touches, so a module that starts using the operator channel
was refused for a declaration it could not see. Over every manifest it stays a refusal.

internal/catalogue/seats_declared.go

@@ -230,6 +230,14 @@ type Shelf map[string]Manifest
 //
 // Run at registration, which is the last moment the mesh can still refuse: after it, a caller is
 // bound to a seat and a refusal is an outage rather than a conversation.
+// UndeclaredSeat ends the problem of a `uses` or a claim naming a seat no manifest given declares: over the whole
+// catalogue (registration, the catalogue's own check) a refusal, and over some manifests alone a seat whose
+// declaring module was not given (novox/hq issue 364).
+const UndeclaredSeat = "which no module declares and the mesh does not define"
+
+// IsUndeclaredSeat says whether a problem CatalogueProblems gave is a seat no manifest given declares.
+func IsUndeclaredSeat(problem string) bool { return strings.HasSuffix(problem, UndeclaredSeat) }
+
 func CatalogueProblems(shelf Shelf) []string {
 	var problems []string
 
@@ -282,7 +290,7 @@ func CatalogueProblems(shelf Shelf) []string {
 		for _, u := range m.Uses {
 			if !exists(u) {
 				problems = append(problems, fmt.Sprintf(
-					"%s uses the seat %q, which no module declares and the mesh does not define",
+					"%s uses the seat %q, "+UndeclaredSeat,
 					module, u))
 			}
 		}
@@ -290,7 +298,7 @@ func CatalogueProblems(shelf Shelf) []string {
 		for _, c := range m.Claims {
 			if !exists(c.Name) {
 				problems = append(problems, fmt.Sprintf(
-					"%s claims the seat %q, which no module declares and the mesh does not define",
+					"%s claims the seat %q, "+UndeclaredSeat,
 					module, c.Name))
 				continue
 			}