Track the correct check id for idempotent service/check updates (#6794)

agent/agent.go

@@ -2248,8 +2248,6 @@ func (a *Agent) addServiceInternal(req *addServiceRequest) error {
 
 	// Create an associated health check
 	for i, chkType := range chkTypes {
-		existingChecks[chkType.CheckID] = true
-
 		checkID := string(chkType.CheckID)
 		if checkID == "" {
 			checkID = fmt.Sprintf("service:%s", service.ID)
@@ -2257,6 +2255,9 @@ func (a *Agent) addServiceInternal(req *addServiceRequest) error {
 				checkID += fmt.Sprintf(":%d", i+1)
 			}
 		}
+
+		existingChecks[types.CheckID(checkID)] = true
+
 		name := chkType.Name
 		if name == "" {
 			name = fmt.Sprintf("Service '%s' check", service.Service)

agent/agent_endpoint_test.go

@@ -2595,8 +2595,9 @@ func testAgent_RegisterService_ReRegister_ReplaceExistingChecks(t *testing.T, ex
 		Port: 8000,
 		Checks: []*structs.CheckType{
 			&structs.CheckType{
-				CheckID: types.CheckID("check_1"),
-				TTL:     20 * time.Second,
+				// explicitly not setting the check id to let it be auto-generated
+				// we want to ensure that we are testing out the cases with autogenerated names/ids
+				TTL: 20 * time.Second,
 			},
 			&structs.CheckType{
 				CheckID: types.CheckID("check_2"),
@@ -2619,8 +2620,7 @@ func testAgent_RegisterService_ReRegister_ReplaceExistingChecks(t *testing.T, ex
 		Port: 8000,
 		Checks: []*structs.CheckType{
 			&structs.CheckType{
-				CheckID: types.CheckID("check_1"),
-				TTL:     20 * time.Second,
+				TTL: 20 * time.Second,
 			},
 			&structs.CheckType{
 				CheckID: types.CheckID("check_3"),
@@ -2644,7 +2644,7 @@ func testAgent_RegisterService_ReRegister_ReplaceExistingChecks(t *testing.T, ex
 		checkIDs = append(checkIDs, string(id))
 	}
 	sort.Strings(checkIDs)
-	require.Equal(t, []string{"check_1", "check_3"}, checkIDs)
+	require.ElementsMatch(t, []string{"service:test:1", "check_3"}, checkIDs)
 }
 
 func TestAgent_RegisterService_TranslateKeys(t *testing.T) {