chore: Fix linter findings for `revive:enforce-slice-style` in `plugins/inputs/[k-o]*` (#16071)

plugins/inputs/kafka_consumer/kafka_consumer_test.go

@@ -418,7 +418,6 @@ func TestConsumerGroupHandlerHandle(t *testing.T) {
 				Topic: "telegraf",
 				Value: []byte("12345"),
 			},
-			expected:            []telegraf.Metric{},
 			expectedHandleError: "message exceeds max_message_len (actual 5, max 4)",
 		},
 		{
@@ -427,7 +426,6 @@ func TestConsumerGroupHandlerHandle(t *testing.T) {
 				Topic: "telegraf",
 				Value: []byte("not an integer"),
 			},
-			expected:            []telegraf.Metric{},
 			expectedHandleError: "strconv.Atoi: parsing \"integer\": invalid syntax",
 		},
 		{

plugins/inputs/kernel/kernel_test.go

@@ -208,7 +208,6 @@ func TestKSMDisabledNoKSMTags(t *testing.T) {
 		statFile:        "testdata/stat_file_full",
 		entropyStatFile: "testdata/entropy_stat_file_full",
 		ksmStatsDir:     "testdata/this_file_does_not_exist",
-		ConfigCollect:   []string{},
 	}
 
 	acc := testutil.Accumulator{}

plugins/inputs/kube_inventory/daemonset_test.go

@@ -15,8 +15,6 @@ import (
 
 func TestDaemonSet(t *testing.T) {
 	cli := &client{}
-	selectInclude := []string{}
-	selectExclude := []string{}
 	now := time.Now()
 	now = time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 1, 36, 0, now.Location())
 	tests := []struct {
@@ -102,9 +100,7 @@ func TestDaemonSet(t *testing.T) {
 
 	for _, v := range tests {
 		ks := &KubernetesInventory{
-			client:          cli,
-			SelectorInclude: selectInclude,
-			SelectorExclude: selectExclude,
+			client: cli,
 		}
 		require.NoError(t, ks.createSelectorFilters())
 		acc := new(testutil.Accumulator)
@@ -193,8 +189,6 @@ func TestDaemonSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 				"selector_select2": "s2",
@@ -207,7 +201,6 @@ func TestDaemonSetSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"select1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -218,7 +211,6 @@ func TestDaemonSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"select2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -231,7 +223,6 @@ func TestDaemonSetSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"*1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -242,7 +233,6 @@ func TestDaemonSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -254,7 +244,6 @@ func TestDaemonSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",

plugins/inputs/kube_inventory/deployment_test.go

@@ -16,8 +16,6 @@ import (
 
 func TestDeployment(t *testing.T) {
 	cli := &client{}
-	selectInclude := []string{}
-	selectExclude := []string{}
 	now := time.Now()
 	now = time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 1, 36, 0, now.Location())
 
@@ -107,9 +105,7 @@ func TestDeployment(t *testing.T) {
 
 	for _, v := range tests {
 		ks := &KubernetesInventory{
-			client:          cli,
-			SelectorInclude: selectInclude,
-			SelectorExclude: selectExclude,
+			client: cli,
 		}
 		require.NoError(t, ks.createSelectorFilters())
 		acc := new(testutil.Accumulator)
@@ -209,8 +205,6 @@ func TestDeploymentSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 				"selector_select2": "s2",
@@ -223,7 +217,6 @@ func TestDeploymentSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"select1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -234,7 +227,6 @@ func TestDeploymentSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"select2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -247,7 +239,6 @@ func TestDeploymentSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"*1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -258,7 +249,6 @@ func TestDeploymentSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -270,7 +260,6 @@ func TestDeploymentSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",

plugins/inputs/kube_inventory/kube_inventory.go

@@ -207,7 +207,7 @@ func init() {
 		return &KubernetesInventory{
 			ResponseTimeout: config.Duration(time.Second * 5),
 			Namespace:       "default",
-			SelectorInclude: []string{},
+			SelectorInclude: make([]string, 0),
 			SelectorExclude: []string{"*"},
 		}
 	})

plugins/inputs/kube_inventory/persistentvolumeclaim_test.go

@@ -15,8 +15,6 @@ import (
 
 func TestPersistentVolumeClaim(t *testing.T) {
 	cli := &client{}
-	selectInclude := []string{}
-	selectExclude := []string{}
 	now := time.Now()
 	now = time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 1, 36, 0, now.Location())
 
@@ -190,9 +188,7 @@ func TestPersistentVolumeClaim(t *testing.T) {
 
 	for _, v := range tests {
 		ks := &KubernetesInventory{
-			client:          cli,
-			SelectorInclude: selectInclude,
-			SelectorExclude: selectExclude,
+			client: cli,
 		}
 		require.NoError(t, ks.createSelectorFilters())
 		acc := new(testutil.Accumulator)
@@ -277,8 +273,6 @@ func TestPersistentVolumeClaimSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 				"selector_select2": "s2",
@@ -291,7 +285,6 @@ func TestPersistentVolumeClaimSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"select1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -302,7 +295,6 @@ func TestPersistentVolumeClaimSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"select2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -315,7 +307,6 @@ func TestPersistentVolumeClaimSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"*1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -326,7 +317,6 @@ func TestPersistentVolumeClaimSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -338,7 +328,6 @@ func TestPersistentVolumeClaimSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",

plugins/inputs/kube_inventory/pod_test.go

@@ -16,8 +16,6 @@ import (
 
 func TestPod(t *testing.T) {
 	cli := &client{}
-	selectInclude := []string{}
-	selectExclude := []string{}
 	now := time.Now()
 	started := time.Date(now.Year(), now.Month(), now.Day(), now.Hour()-1, 1, 36, 0, now.Location())
 	created := time.Date(now.Year(), now.Month(), now.Day(), now.Hour()-2, 1, 0, 0, now.Location())
@@ -441,9 +439,7 @@ func TestPod(t *testing.T) {
 	}
 	for _, v := range tests {
 		ks := &KubernetesInventory{
-			client:          cli,
-			SelectorInclude: selectInclude,
-			SelectorExclude: selectExclude,
+			client: cli,
 		}
 		require.NoError(t, ks.createSelectorFilters())
 		acc := new(testutil.Accumulator)
@@ -607,8 +603,6 @@ func TestPodSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
-			exclude:  []string{},
 			expected: map[string]string{
 				"node_selector_select1": "s1",
 				"node_selector_select2": "s2",
@@ -621,7 +615,6 @@ func TestPodSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"select1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"node_selector_select1": "s1",
 			},
@@ -632,7 +625,6 @@ func TestPodSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"select2"},
 			expected: map[string]string{
 				"node_selector_select1": "s1",
@@ -645,7 +637,6 @@ func TestPodSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"*1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"node_selector_select1": "s1",
 			},
@@ -656,7 +647,6 @@ func TestPodSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"node_selector_select1": "s1",
@@ -668,7 +658,6 @@ func TestPodSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"node_selector_select1": "s1",
@@ -705,8 +694,6 @@ func TestPodSelectorFilter(t *testing.T) {
 
 func TestPodPendingContainers(t *testing.T) {
 	cli := &client{}
-	selectInclude := []string{}
-	selectExclude := []string{}
 	now := time.Now()
 	started := time.Date(now.Year(), now.Month(), now.Day(), now.Hour()-1, 1, 36, 0, now.Location())
 	created := time.Date(now.Year(), now.Month(), now.Day(), now.Hour()-2, 1, 36, 0, now.Location())
@@ -808,7 +795,6 @@ func TestPodPendingContainers(t *testing.T) {
 											LastTransitionTime: metav1.Time{Time: cond1},
 										},
 									},
-									ContainerStatuses: []corev1.ContainerStatus{},
 								},
 								ObjectMeta: metav1.ObjectMeta{
 									OwnerReferences: []metav1.OwnerReference{
@@ -988,9 +974,7 @@ func TestPodPendingContainers(t *testing.T) {
 	}
 	for _, v := range tests {
 		ks := &KubernetesInventory{
-			client:          cli,
-			SelectorInclude: selectInclude,
-			SelectorExclude: selectExclude,
+			client: cli,
 		}
 		require.NoError(t, ks.createSelectorFilters())
 		acc := new(testutil.Accumulator)

plugins/inputs/kube_inventory/resourcequotas_test.go

@@ -30,7 +30,6 @@ func TestResourceQuota(t *testing.T) {
 					"/resourcequotas/": corev1.ResourceQuotaList{},
 				},
 			},
-			output:   []telegraf.Metric{},
 			hasError: false,
 		},
 		{

plugins/inputs/kube_inventory/service_test.go

@@ -191,8 +191,6 @@ func TestServiceSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 				"selector_select2": "s2",
@@ -205,7 +203,6 @@ func TestServiceSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"select1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -216,7 +213,6 @@ func TestServiceSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"select2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -229,7 +225,6 @@ func TestServiceSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"*1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -240,7 +235,6 @@ func TestServiceSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -252,7 +246,6 @@ func TestServiceSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",

plugins/inputs/kube_inventory/statefulset_test.go

@@ -15,8 +15,6 @@ import (
 
 func TestStatefulSet(t *testing.T) {
 	cli := &client{}
-	selectInclude := []string{}
-	selectExclude := []string{}
 	now := time.Now()
 	now = time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 1, 36, 0, now.Location())
 	tests := []struct {
@@ -204,9 +202,7 @@ func TestStatefulSet(t *testing.T) {
 
 	for _, v := range tests {
 		ks := &KubernetesInventory{
-			client:          cli,
-			SelectorInclude: selectInclude,
-			SelectorExclude: selectExclude,
+			client: cli,
 		}
 		require.NoError(t, ks.createSelectorFilters())
 		acc := &testutil.Accumulator{}
@@ -292,8 +288,6 @@ func TestStatefulSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 				"selector_select2": "s2",
@@ -306,7 +300,6 @@ func TestStatefulSetSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"select1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -317,7 +310,6 @@ func TestStatefulSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"select2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -330,7 +322,6 @@ func TestStatefulSetSelectorFilter(t *testing.T) {
 			},
 			hasError: false,
 			include:  []string{"*1"},
-			exclude:  []string{},
 			expected: map[string]string{
 				"selector_select1": "s1",
 			},
@@ -341,7 +332,6 @@ func TestStatefulSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",
@@ -353,7 +343,6 @@ func TestStatefulSetSelectorFilter(t *testing.T) {
 				responseMap: responseMap,
 			},
 			hasError: false,
-			include:  []string{},
 			exclude:  []string{"*2"},
 			expected: map[string]string{
 				"selector_select1": "s1",

plugins/inputs/kubernetes/kubernetes.go

@@ -51,7 +51,6 @@ type Kubernetes struct {
 func init() {
 	inputs.Add("kubernetes", func() telegraf.Input {
 		return &Kubernetes{
-			LabelInclude: []string{},
 			LabelExclude: []string{"*"},
 		}
 	})

plugins/inputs/ldap/ldap_test.go

@@ -33,8 +33,6 @@ func TestMockResult(t *testing.T) {
 				Attributes: []*ldap.EntryAttribute{{Name: "monitorCounter", Values: []string{"1"}}},
 			},
 		},
-		Referrals: []string{},
-		Controls:  []ldap.Control{},
 	}
 
 	// Setup the plugin

plugins/inputs/libvirt/libvirt_test.go

@@ -102,7 +102,7 @@ func TestLibvirt_Gather(t *testing.T) {
 			StatisticsGroups: []string{"state"},
 		}
 		mockLibvirtUtils.On("EnsureConnected", mock.Anything).Return(nil).Once().
-			On("GatherAllDomains", mock.Anything).Return([]golibvirt.Domain{}, nil).Once()
+			On("GatherAllDomains", mock.Anything).Return(nil, nil).Once()
 
 		err := l.Gather(&acc)
 		require.NoError(t, err)
@@ -207,11 +207,9 @@ func TestLibvirt_GatherMetrics(t *testing.T) {
 			var acc testutil.Accumulator
 			mockLibvirtUtils := MockLibvirtUtils{}
 			l := Libvirt{
-				utils:                &mockLibvirtUtils,
-				Log:                  testutil.Logger{},
-				StatisticsGroups:     []string{},
-				Domains:              test.excludeDomains,
-				AdditionalStatistics: []string{},
+				utils:   &mockLibvirtUtils,
+				Log:     testutil.Logger{},
+				Domains: test.excludeDomains,
 			}
 
 			mockLibvirtUtils.On("EnsureConnected", mock.Anything).Return(nil).Once().
@@ -223,7 +221,7 @@ func TestLibvirt_GatherMetrics(t *testing.T) {
 				l.metricNumber = domainStatsVCPU
 				mockLibvirtUtils.On("GatherNumberOfPCPUs").Return(4, nil).Once().
 					On("GatherVcpuMapping", domains[0], mock.Anything, mock.Anything).Return(test.vcpuMapping, nil).Once().
-					On("GatherVcpuMapping", domains[1], mock.Anything, mock.Anything).Return([]vcpuAffinity{}, nil).Once()
+					On("GatherVcpuMapping", domains[1], mock.Anything, mock.Anything).Return(nil, nil).Once()
 			}
 
 			err := l.Gather(&acc)

plugins/inputs/libvirt/libvirt_utils.go

@@ -40,7 +40,7 @@ func (l *utilsImpl) GatherAllDomains() (domains []golibvirt.Domain, err error) {
 func (l *utilsImpl) GatherStatsForDomains(domains []golibvirt.Domain, metricNumber uint32) ([]golibvirt.DomainStatsRecord, error) {
 	if metricNumber == 0 {
 		// do not need to do expensive call if no stats were set to gather
-		return []golibvirt.DomainStatsRecord{}, nil
+		return nil, nil
 	}
 
 	allDomainStatesFlag := golibvirt.ConnectGetAllDomainsStatsRunning + golibvirt.ConnectGetAllDomainsStatsPaused +

plugins/inputs/mesos/mesos.go

@@ -175,7 +175,7 @@ func (m *Mesos) createHTTPClient() (*http.Client, error) {
 
 // metricsDiff() returns set names for removal
 func metricsDiff(role Role, w []string) []string {
-	b := []string{}
+	b := make([]string, 0, len(allMetrics[role]))
 	s := make(map[string]bool)
 
 	if len(w) == 0 {
@@ -269,8 +269,8 @@ func (m *Mesos) getMetrics(role Role, group string) []string {
 		// framework_offers and allocator metrics have unpredictable names, so they can't be listed here.
 		// These empty groups are included to prevent the "unknown metrics group" info log below.
 		// filterMetrics() filters these metrics by looking for names with the corresponding prefix.
-		metrics["framework_offers"] = []string{}
-		metrics["allocator"] = []string{}
+		metrics["framework_offers"] = make([]string, 0)
+		metrics["allocator"] = make([]string, 0)
 
 		metrics["tasks"] = []string{
 			"master/tasks_error",
@@ -432,8 +432,8 @@ func (m *Mesos) getMetrics(role Role, group string) []string {
 	ret, ok := metrics[group]
 
 	if !ok {
-		m.Log.Infof("unknown role %q metrics group: %s", role, group)
-		return []string{}
+		m.Log.Infof("Unknown role %q metrics group: %s", role, group)
+		return nil
 	}
 
 	return ret

plugins/inputs/mesos/mesos_test.go

@@ -373,9 +373,8 @@ func TestMesosSlave(t *testing.T) {
 	var acc testutil.Accumulator
 
 	m := Mesos{
-		Log:     testutil.Logger{},
-		Masters: []string{},
-		Slaves:  []string{slaveTestServer.Listener.Addr().String()},
+		Log:    testutil.Logger{},
+		Slaves: []string{slaveTestServer.Listener.Addr().String()},
 		// SlaveTasks: true,
 		Timeout: 10,
 	}

plugins/inputs/minecraft/client.go

@@ -103,7 +103,7 @@ func (c *client) Scores(player string) ([]Score, error) {
 func parsePlayers(input string) []string {
 	parts := strings.SplitAfterN(input, ":", 2)
 	if len(parts) != 2 {
-		return []string{}
+		return nil
 	}
 
 	names := strings.Split(parts[1], ",")
@@ -135,7 +135,7 @@ type Score struct {
 
 func parseScores(input string) []Score {
 	if strings.Contains(input, "has no scores") {
-		return []Score{}
+		return nil
 	}
 
 	// Detect Minecraft <= 1.12

plugins/inputs/minecraft/client_test.go

@@ -33,7 +33,6 @@ func TestClient_Player(t *testing.T) {
 			commands: map[string]string{
 				"scoreboard players list": "There are no tracked players on the scoreboard",
 			},
-			expected: []string{},
 		},
 		{
 			name: "minecraft 1.12 single player",
@@ -75,7 +74,6 @@ func TestClient_Player(t *testing.T) {
 			commands: map[string]string{
 				"scoreboard players list": "There are no tracked entities",
 			},
-			expected: []string{},
 		},
 		{
 			name: "minecraft 1.13 single player",
@@ -120,7 +118,6 @@ func TestClient_Scores(t *testing.T) {
 			commands: map[string]string{
 				"scoreboard players list Etho": "Player Etho has no scores recorded",
 			},
-			expected: []Score{},
 		},
 		{
 			name:   "minecraft 1.12 player with one score",
@@ -150,7 +147,6 @@ func TestClient_Scores(t *testing.T) {
 			commands: map[string]string{
 				"scoreboard players list Etho": "Etho has no scores to show",
 			},
-			expected: []Score{},
 		},
 		{
 			name:   "minecraft 1.13 player with one score",

plugins/inputs/minecraft/minecraft_test.go

@@ -43,10 +43,9 @@ func TestGather(t *testing.T) {
 					return nil
 				},
 				PlayersF: func() ([]string, error) {
-					return []string{}, nil
+					return nil, nil
 				},
 			},
-			metrics: []telegraf.Metric{},
 		},
 		{
 			name: "one player without scores",
@@ -60,13 +59,12 @@ func TestGather(t *testing.T) {
 				ScoresF: func(player string) ([]Score, error) {
 					switch player {
 					case "Etho":
-						return []Score{}, nil
+						return nil, nil
 					default:
 						panic("unknown player")
 					}
 				},
 			},
-			metrics: []telegraf.Metric{},
 		},
 		{
 			name: "one player with scores",

plugins/inputs/modbus/configuration.go

@@ -17,7 +17,7 @@ type Configuration interface {
 
 func removeDuplicates(elements []uint16) []uint16 {
 	encountered := make(map[uint16]bool, len(elements))
-	result := []uint16{}
+	result := make([]uint16, 0, len(elements))
 
 	for _, addr := range elements {
 		if !encountered[addr] {

plugins/inputs/modbus/configuration_register_test.go

@@ -947,7 +947,7 @@ func TestRegisterReadMultipleCoilWithHole(t *testing.T) {
 	defer handler.Close()
 	client := mb.NewClient(handler)
 
-	fcs := []fieldDefinition{}
+	fcs := make([]fieldDefinition, 0, 26)
 	expectedFields := make(map[string]interface{})
 	writeValue := uint16(0)
 	readValue := uint16(0)
@@ -1032,7 +1032,7 @@ func TestRegisterReadMultipleCoilLimit(t *testing.T) {
 	defer handler.Close()
 	client := mb.NewClient(handler)
 
-	fcs := []fieldDefinition{}
+	fcs := make([]fieldDefinition, 0, 4000)
 	expectedFields := make(map[string]interface{})
 	writeValue := uint16(0)
 	readValue := uint16(0)
@@ -1091,7 +1091,7 @@ func TestRegisterReadMultipleHoldingRegisterWithHole(t *testing.T) {
 	defer handler.Close()
 	client := mb.NewClient(handler)
 
-	fcs := []fieldDefinition{}
+	fcs := make([]fieldDefinition, 0, 20)
 	expectedFields := make(map[string]interface{})
 	for i := 0; i < 10; i++ {
 		fc := fieldDefinition{
@@ -1165,7 +1165,7 @@ func TestRegisterReadMultipleHoldingRegisterLimit(t *testing.T) {
 	defer handler.Close()
 	client := mb.NewClient(handler)
 
-	fcs := []fieldDefinition{}
+	fcs := make([]fieldDefinition, 0, 401)
 	expectedFields := make(map[string]interface{})
 	for i := 0; i <= 400; i++ {
 		fc := fieldDefinition{}

plugins/inputs/modbus/configuration_request.go

@@ -231,12 +231,7 @@ func (c *ConfigurationPerRequest) Process() (map[byte]requestSet, error) {
 		// Make sure we have a set to work with
 		set, found := result[def.SlaveID]
 		if !found {
-			set = requestSet{
-				coil:     []request{},
-				discrete: []request{},
-				holding:  []request{},
-				input:    []request{},
-			}
+			set = requestSet{}
 		}
 
 		params := groupingParams{

plugins/inputs/modbus/configuration_request_test.go

@@ -1731,7 +1731,6 @@ func TestRequestFail(t *testing.T) {
 					SlaveID:      1,
 					ByteOrder:    "AB",
 					RegisterType: "coil",
-					Fields:       []requestFieldDefinition{},
 				},
 			},
 			errormsg: "configuration invalid: unknown byte-order \"AB\"",
@@ -1794,7 +1793,6 @@ func TestRequestFail(t *testing.T) {
 					SlaveID:      1,
 					ByteOrder:    "AB",
 					RegisterType: "discrete",
-					Fields:       []requestFieldDefinition{},
 				},
 			},
 			errormsg: "configuration invalid: unknown byte-order \"AB\"",
@@ -1857,7 +1855,6 @@ func TestRequestFail(t *testing.T) {
 					SlaveID:      1,
 					ByteOrder:    "AB",
 					RegisterType: "holding",
-					Fields:       []requestFieldDefinition{},
 				},
 			},
 			errormsg: "configuration invalid: unknown byte-order \"AB\"",
@@ -1969,7 +1966,6 @@ func TestRequestFail(t *testing.T) {
 					SlaveID:      1,
 					ByteOrder:    "AB",
 					RegisterType: "input",
-					Fields:       []requestFieldDefinition{},
 				},
 			},
 			errormsg: "configuration invalid: unknown byte-order \"AB\"",
@@ -2326,7 +2322,7 @@ func TestRequestMultipleSlavesOneFail(t *testing.T) {
 
 			if tcpframe.Device == 2 {
 				// Simulate device 2 being unavailable
-				return []byte{}, &mbserver.GatewayTargetDeviceFailedtoRespond
+				return nil, &mbserver.GatewayTargetDeviceFailedtoRespond
 			}
 			return []byte{0x02, 0x00, 0x42}, &mbserver.Success
 		},

plugins/inputs/modbus/request.go

@@ -28,7 +28,6 @@ func splitMaxBatchSize(g request, maxBatchSize uint16) []request {
 	idx := 0
 	for start := g.address; start < g.address+g.length; {
 		current := request{
-			fields:  []field{},
 			address: start,
 		}
 
@@ -238,7 +237,6 @@ func groupFieldsToRequests(fields []field, params groupingParams) []request {
 			groups = append(groups, current)
 		}
 		current = request{
-			fields:  []field{},
 			address: f.address,
 			length:  f.length,
 		}

plugins/inputs/mongodb/mongodb_data.go

@@ -34,7 +34,6 @@ func NewMongodbData(statLine *statLine, tags map[string]string) *MongodbData {
 		StatLine: statLine,
 		Tags:     tags,
 		Fields:   make(map[string]interface{}),
-		DbData:   []DbData{},
 	}
 }
 

plugins/inputs/neptune_apex/neptune_apex_test.go

@@ -34,8 +34,7 @@ func TestGather(t *testing.T) {
 			servers: []string{"http://abc", "https://def"},
 		},
 		{
-			name:    "Good case, 0 servers",
-			servers: []string{},
+			name: "Good case, 0 servers",
 		},
 		{
 			name:    "Good case nil",

plugins/inputs/netflow/type_conversion_test.go

@@ -269,7 +269,6 @@ func TestDecodeIPv4Options(t *testing.T) {
 	}{
 		{
 			name:     "none",
-			bits:     []int{},
 			expected: "",
 		},
 		{
@@ -323,12 +322,10 @@ func TestDecodeTCPFlags(t *testing.T) {
 	}{
 		{
 			name:     "none",
-			bits:     []int{},
 			expected: "........",
 		},
 		{
 			name:     "none IPFIX",
-			bits:     []int{},
 			expected: "................",
 			ipfix:    true,
 		},
@@ -423,7 +420,6 @@ func TestDecodeFragmentFlags(t *testing.T) {
 	}{
 		{
 			name:     "none",
-			bits:     []int{},
 			expected: "........",
 		},
 		{

plugins/inputs/opcua/opcua_test.go

@@ -192,7 +192,7 @@ func TestReadClientIntegrationAdditionalFields(t *testing.T) {
 		"The operation succeeded. StatusGood (0x0)",
 		"The operation succeeded. StatusGood (0x0)",
 	}
-	expectedopcmetrics := []telegraf.Metric{}
+	expectedopcmetrics := make([]telegraf.Metric, 0, len(testopctags))
 	for i, x := range testopctags {
 		now := time.Now()
 		tags := map[string]string{
@@ -233,8 +233,7 @@ func TestReadClientIntegrationAdditionalFields(t *testing.T) {
 
 	require.NoError(t, client.Connect())
 
-	actualopcmetrics := []telegraf.Metric{}
-
+	actualopcmetrics := make([]telegraf.Metric, 0, len(client.LastReceivedData))
 	for i := range client.LastReceivedData {
 		actualopcmetrics = append(actualopcmetrics, client.MetricForNode(i))
 	}

plugins/inputs/opcua_listener/opcua_listener_test.go

@@ -281,7 +281,7 @@ func TestSubscribeClientIntegrationAdditionalFields(t *testing.T) {
 		"The operation succeeded. StatusGood (0x0)",
 		"The operation succeeded. StatusGood (0x0)",
 	}
-	expectedopcmetrics := []telegraf.Metric{}
+	expectedopcmetrics := make([]telegraf.Metric, 0, len(testopctags))
 	for i, x := range testopctags {
 		now := time.Now()
 		tags := map[string]string{

plugins/inputs/opcua_listener/subscribe_client.go

@@ -152,10 +152,6 @@ func (o *SubscribeClient) Stop(ctx context.Context) <-chan struct{} {
 	return closing
 }
 
-func (o *SubscribeClient) CurrentValues() ([]telegraf.Metric, error) {
-	return []telegraf.Metric{}, nil
-}
-
 func (o *SubscribeClient) StartStreamValues(ctx context.Context) (<-chan telegraf.Metric, error) {
 	err := o.Connect()
 	if err != nil {

plugins/inputs/openldap/openldap_test.go

@@ -28,8 +28,6 @@ func TestOpenldapMockResult(t *testing.T) {
 				Attributes: []*ldap.EntryAttribute{{Name: "monitorCounter", Values: []string{"1"}}},
 			},
 		},
-		Referrals: []string{},
-		Controls:  []ldap.Control{},
 	}
 
 	o := &Openldap{

plugins/inputs/opensearch_query/opensearch_query_test.go

@@ -242,7 +242,6 @@ func testData() []osAggregationQueryTest {
 				FilterQuery:     "response: 200",
 				DateField:       "@timestamp",
 				QueryPeriod:     queryPeriod,
-				Tags:            []string{},
 				mapMetricFields: map[string]string{},
 			},
 			expectedMetrics: []telegraf.Metric{
@@ -264,7 +263,6 @@ func testData() []osAggregationQueryTest {
 				MetricFunction:  "max",
 				DateField:       "@timestamp",
 				QueryPeriod:     queryPeriod,
-				Tags:            []string{},
 				mapMetricFields: map[string]string{"size": "long"},
 			},
 			expectedMetrics: []telegraf.Metric{
@@ -286,7 +284,6 @@ func testData() []osAggregationQueryTest {
 				MetricFunction:  "average",
 				DateField:       "@timestamp",
 				QueryPeriod:     queryPeriod,
-				Tags:            []string{},
 				mapMetricFields: map[string]string{"size": "long"},
 			},
 			wantInitErr: true,
@@ -299,7 +296,6 @@ func testData() []osAggregationQueryTest {
 				MetricFields:    []string{"none"},
 				DateField:       "@timestamp",
 				QueryPeriod:     queryPeriod,
-				Tags:            []string{},
 				mapMetricFields: map[string]string{},
 			},
 			wantQueryResErr: true,
@@ -312,7 +308,6 @@ func testData() []osAggregationQueryTest {
 				MeasurementName: "measurement11",
 				DateField:       "@timestamp",
 				QueryPeriod:     queryPeriod,
-				Tags:            []string{},
 				mapMetricFields: map[string]string{},
 			},
 			wantQueryResErr: true,
@@ -326,7 +321,6 @@ func testData() []osAggregationQueryTest {
 				MetricFunction:  "avg",
 				DateField:       "@notatimestamp",
 				QueryPeriod:     queryPeriod,
-				Tags:            []string{},
 				mapMetricFields: map[string]string{"size": "long"},
 			},
 			expectedMetrics: []telegraf.Metric{
@@ -360,7 +354,6 @@ func testData() []osAggregationQueryTest {
 				DateField:       "@timestamp",
 				DateFieldFormat: "yyyy",
 				QueryPeriod:     queryPeriod,
-				Tags:            []string{},
 				mapMetricFields: map[string]string{},
 			},
 			wantQueryResErr: true,