feat(routes): better error message in case of missing annotations (#1150)

putting this info into error detail would be ideal, but skopeo
doesn't print them, so overwrite the error message.

Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>

pkg/api/errors.go

@@ -11,6 +11,12 @@ type Error struct {
 	Detail      interface{} `json:"detail,omitempty"`
 }
 
+func (e Error) WithMessage(msg string) Error {
+	e.Message = msg
+
+	return e
+}
+
 type ErrorList struct {
 	Errors []*Error `json:"errors"`
 }

pkg/api/routes.go

@@ -587,7 +587,7 @@ func (rh *RouteHandler) UpdateManifest(response http.ResponseWriter, request *ht
 				NewErrorList(NewError(INVALID_INDEX, map[string]string{"name": name})))
 		} else if errors.Is(err, zerr.ErrImageLintAnnotations) {
 			WriteJSON(response, http.StatusBadRequest,
-				NewErrorList(NewError(MANIFEST_INVALID, map[string]string{"reference": reference})))
+				NewErrorList(NewError(MANIFEST_INVALID, map[string]string{"reference": reference}).WithMessage(err.Error())))
 		} else {
 			// could be syscall.EMFILE (Err:0x18 too many opened files), etc
 			rh.c.Log.Error().Err(err).Msg("unexpected error: performing cleanup")