Folders: Fix error handling for zanzana (#115056)

pkg/api/apierrors/folder.go

@@ -57,7 +57,11 @@ func ToFolderErrorResponse(err error) response.Response {
 	// --- Kubernetes status errors ---
 	var statusErr *k8sErrors.StatusError
 	if errors.As(err, &statusErr) {
-		return response.Error(int(statusErr.ErrStatus.Code), statusErr.ErrStatus.Message, err)
+		message := statusErr.ErrStatus.Message
+		if message == "" {
+			message = getDefaultMessageForStatus(int(statusErr.ErrStatus.Code))
+		}
+		return response.Error(int(statusErr.ErrStatus.Code), message, err)
 	}
 
 	return response.ErrOrFallback(http.StatusInternalServerError, fmt.Sprintf("Folder API error: %s", err.Error()), err)
@@ -100,6 +104,19 @@ func ToFolderStatusError(err error) k8sErrors.StatusError {
 	}
 }
 
+func getDefaultMessageForStatus(statusCode int) string {
+	switch statusCode {
+	case http.StatusForbidden:
+		return "Access denied"
+	case http.StatusNotFound:
+		return "Folder not found"
+	case http.StatusBadRequest:
+		return "Invalid request"
+	default:
+		return "Folder API error"
+	}
+}
+
 func IsForbidden(err error) bool {
 	return k8sErrors.IsForbidden(err) || errors.Is(err, dashboards.ErrFolderAccessDenied)
 }