Fixed apigw payload processer invalid function registration

pkg/apigw/filter/processer.go

@@ -203,7 +203,9 @@ func (h *processerPayload) Merge(params []byte) (types.Handler, error) {
 		return nil, errors.New("could not register function, body empty")
 	}
 
-	h.fn, _ = h.vm.RegisterFunction(h.params.Func)
+	if h.fn, err = h.vm.RegisterFunction(h.params.Func); err != nil {
+		return nil, fmt.Errorf("could not register function, invalid body: %s", err)
+	}
 
 	return h, err
 }

pkg/apigw/filter/processer_test.go

@@ -162,6 +162,15 @@ func Test_processerPayload(t *testing.T) {
 				params: prepareFuncPayload(t, ``),
 				errv:   `could not register function, body empty`,
 			},
+			{
+				name: "payload processer invalid body",
+				rq: &http.Request{
+					Method: "POST",
+					Body:   ioutil.NopCloser(strings.NewReader(`[{"name":"johnny", "surname":"mnemonic"},{"name":"johnny", "surname":"knoxville"}]`)),
+				},
+				params: prepareFuncPayload(t, `.foo`),
+				errv:   `could not register function, invalid body: could not transform payload: Unexpected "."`,
+			},
 		}
 	)