Support marshalling YANG empty values for TogNMINotifications. (#836)

* Support marshalling YANG empty values for TogNMINotifications.

* Add a couple more tests to clarify behaviour when empty is part of a union type

* Fix and remove .swp file

Author: wenovus

testutil/.testutil.go.swp

@@ -568,6 +568,16 @@ func findUpdatedLeaves(leaves any, s GoStruct, parent *gnmiPath) error {
 				addLeaf(&path{p}, fval.Interface())
 			}
 			continue
+		case reflect.Bool:
+			if fval.Type().Name() == EmptyTypeName {
+				// This is an empty value.
+				// Only marshal if the empty leaf is present.
+				if val := fval.Bool(); val {
+					for _, p := range mapPaths {
+						addLeaf(&path{p}, fval.Interface())
+					}
+				}
+			}
 		}
 	}
 	return errs.Err()

ygot/render.go

@@ -1054,6 +1054,17 @@ func TestTogNMINotifications(t *testing.T) {
 				Val:  &gnmipb.TypedValue{Value: &gnmipb.TypedValue_DoubleVal{42.0}},
 			}},
 		}},
+	}, {
+		name:        "simple empty value leaf example",
+		inTimestamp: 42,
+		inStruct:    &renderExample{Empty: true},
+		want: []*gnmipb.Notification{{
+			Timestamp: 42,
+			Update: []*gnmipb.Update{{
+				Path: &gnmipb.Path{Element: []string{"empty"}},
+				Val:  &gnmipb.TypedValue{Value: &gnmipb.TypedValue_BoolVal{true}},
+			}},
+		}},
 	}, {
 		name:        "struct with invalid GoStruct map",
 		inTimestamp: 42,
@@ -1174,6 +1185,17 @@ func TestTogNMINotifications(t *testing.T) {
 				Val:  &gnmipb.TypedValue{Value: &gnmipb.TypedValue_BytesVal{[]byte(base64testString)}},
 			}},
 		}},
+	}, {
+		name:        "struct with empty union",
+		inTimestamp: 42,
+		inStruct:    &renderExample{UnionValSimple: testutil.YANGEmpty(false)},
+		want: []*gnmipb.Notification{{
+			Timestamp: 42,
+			Update: []*gnmipb.Update{{
+				Path: &gnmipb.Path{Element: []string{"union-val-simple"}},
+				Val:  &gnmipb.TypedValue{Value: &gnmipb.TypedValue_BoolVal{false}},
+			}},
+		}},
 	}, {
 		name:        "string with leaf-list of union",
 		inTimestamp: 42,
@@ -1183,6 +1205,8 @@ func TestTogNMINotifications(t *testing.T) {
 				EnumTestVALTWO,
 				testutil.UnionInt64(42),
 				testutil.UnionFloat64(3.14),
+				testutil.YANGEmpty(true),
+				testutil.YANGEmpty(false),
 			},
 		},
 		want: []*gnmipb.Notification{{
@@ -1200,6 +1224,10 @@ func TestTogNMINotifications(t *testing.T) {
 								Value: &gnmipb.TypedValue_IntVal{42},
 							}, {
 								Value: &gnmipb.TypedValue_DoubleVal{3.14},
+							}, {
+								Value: &gnmipb.TypedValue_BoolVal{true},
+							}, {
+								Value: &gnmipb.TypedValue_BoolVal{false},
 							}},
 						},
 					},