chore: Enable `revive:enforce-slice-style` rule (#16173)

.golangci.yml

@@ -265,6 +265,8 @@ linters-settings:
       - name: enforce-map-style
         arguments: ["make"]
         exclude: [ "TEST" ]
+      - name: enforce-slice-style
+        arguments: ["make"]
       - name: error-naming
       - name: error-return
       - name: error-strings

agent/accumulator_test.go

@@ -127,7 +127,7 @@ func TestSetPrecision(t *testing.T) {
 
 func TestAddTrackingMetricGroupEmpty(t *testing.T) {
 	ch := make(chan telegraf.Metric, 10)
-	metrics := []telegraf.Metric{}
+	metrics := make([]telegraf.Metric, 0)
 	acc := NewAccumulator(&TestMetricMaker{}, ch).WithTracking(1)
 
 	id := acc.AddTrackingMetricGroup(metrics)

agent/agent_test.go

@@ -83,7 +83,6 @@ func TestAgent_LoadOutput(t *testing.T) {
 	require.Len(t, a.Config.Outputs, 1)
 
 	c = config.NewConfig()
-	c.OutputFilters = []string{}
 	err = c.LoadConfig("../config/testdata/telegraf-agent.toml")
 	require.NoError(t, err)
 	a = NewAgent(c)

agent/tick_test.go

@@ -37,8 +37,7 @@ func TestAlignedTicker(t *testing.T) {
 		time.Unix(60, 0).UTC(),
 	}
 
-	actual := []time.Time{}
-
+	actual := make([]time.Time, 0)
 	clk.Add(10 * time.Second)
 	for !clk.Now().After(until) {
 		tm := <-ticker.Elapsed()
@@ -109,8 +108,7 @@ func TestAlignedTickerOffset(t *testing.T) {
 		time.Unix(53, 0).UTC(),
 	}
 
-	actual := []time.Time{}
-
+	actual := make([]time.Time, 0)
 	clk.Add(10*time.Second + offset)
 	for !clk.Now().After(until) {
 		tm := <-ticker.Elapsed()
@@ -174,7 +172,7 @@ func TestUnalignedTicker(t *testing.T) {
 		time.Unix(61, 0).UTC(),
 	}
 
-	actual := []time.Time{}
+	actual := make([]time.Time, 0)
 	for !clk.Now().After(until) {
 		select {
 		case tm := <-ticker.Elapsed():
@@ -215,7 +213,7 @@ func TestRollingTicker(t *testing.T) {
 		time.Unix(61, 0).UTC(),
 	}
 
-	actual := []time.Time{}
+	actual := make([]time.Time, 0)
 	for !clk.Now().After(until) {
 		select {
 		case tm := <-ticker.Elapsed():

cmd/telegraf/cmd_win_service_notwindows.go

@@ -9,7 +9,7 @@ import (
 )
 
 func cliFlags() []cli.Flag {
-	return []cli.Flag{}
+	return make([]cli.Flag, 0)
 }
 
 func getServiceCommands(io.Writer) []*cli.Command {

cmd/telegraf/printer.go

@@ -24,7 +24,7 @@ var (
 	inputDefaults = []string{"cpu", "mem", "swap", "system", "kernel", "processes", "disk", "diskio"}
 
 	// Default output plugins
-	outputDefaults = []string{}
+	outputDefaults = make([]string, 0)
 )
 
 var header = `# Telegraf Configuration
@@ -126,7 +126,7 @@ func printSampleConfig(outputBuffer io.Writer, filters Filters) {
 			printFilteredSecretstores(secretstoreFilters, false, outputBuffer)
 		} else {
 			fmt.Print(secretstoreHeader)
-			snames := []string{}
+			snames := make([]string, 0, len(secretstores.SecretStores))
 			for sname := range secretstores.SecretStores {
 				snames = append(snames, sname)
 			}
@@ -165,7 +165,7 @@ func printSampleConfig(outputBuffer io.Writer, filters Filters) {
 			printFilteredProcessors(processorFilters, false, outputBuffer)
 		} else {
 			outputBuffer.Write([]byte(processorHeader))
-			pnames := []string{}
+			pnames := make([]string, 0, len(processors.Processors))
 			for pname := range processors.Processors {
 				pnames = append(pnames, pname)
 			}
@@ -182,7 +182,7 @@ func printSampleConfig(outputBuffer io.Writer, filters Filters) {
 			printFilteredAggregators(aggregatorFilters, false, outputBuffer)
 		} else {
 			outputBuffer.Write([]byte(aggregatorHeader))
-			pnames := []string{}
+			pnames := make([]string, 0, len(aggregators.Aggregators))
 			for pname := range aggregators.Aggregators {
 				pnames = append(pnames, pname)
 			}
@@ -261,7 +261,7 @@ func printFilteredInputs(inputFilters []string, commented bool, outputBuffer io.
 	// cache service inputs to print them at the end
 	servInputs := make(map[string]telegraf.ServiceInput)
 	// for alphabetical looping:
-	servInputNames := []string{}
+	servInputNames := make([]string, 0, len(pnames))
 
 	// Print Inputs
 	for _, pname := range pnames {

config/config.go

@@ -434,7 +434,7 @@ func GetDefaultConfigPath() ([]string, error) {
 
 	// At this point we need to check if the files under /etc/telegraf are
 	// populated and return them all.
-	confFiles := []string{}
+	confFiles := make([]string, 0)
 	if _, err := os.Stat(etcfile); err == nil {
 		confFiles = append(confFiles, etcfile)
 	}
@@ -1805,7 +1805,7 @@ func (c *Config) getFieldTagFilter(tbl *ast.Table, fieldName string) []models.Ta
 }
 
 func keys(m map[string]bool) []string {
-	result := []string{}
+	result := make([]string, 0, len(m))
 	for k := range m {
 		result = append(result, k)
 	}

config/config_test.go

@@ -479,8 +479,6 @@ func TestConfig_InlineTables(t *testing.T) {
 }
 
 func TestConfig_SliceComment(t *testing.T) {
-	t.Skipf("Skipping until #3642 is resolved")
-
 	c := config.NewConfig()
 	require.NoError(t, c.LoadConfig("./testdata/slice_comment.toml"))
 	require.Len(t, c.Outputs, 1)
@@ -1575,7 +1573,6 @@ func (m *MockupStatePlugin) Init() error {
 	}
 	m.state = MockupState{
 		Name:     "mockup",
-		Bits:     []int{},
 		Modified: t0,
 	}
 

config/secret_test.go

@@ -67,7 +67,7 @@ func TestGettingMissingResolver(t *testing.T) {
 	mysecret := "a @{referenced:secret}"
 	s := NewSecret([]byte(mysecret))
 	defer s.Destroy()
-	s.unlinked = []string{}
+	s.unlinked = make([]string, 0)
 	s.resolvers = map[string]telegraf.ResolveFunc{
 		"@{a:dummy}": func() ([]byte, bool, error) {
 			return nil, false, nil
@@ -82,7 +82,7 @@ func TestGettingResolverError(t *testing.T) {
 	mysecret := "a @{referenced:secret}"
 	s := NewSecret([]byte(mysecret))
 	defer s.Destroy()
-	s.unlinked = []string{}
+	s.unlinked = make([]string, 0)
 	s.resolvers = map[string]telegraf.ResolveFunc{
 		"@{referenced:secret}": func() ([]byte, bool, error) {
 			return nil, false, errors.New("broken")
@@ -111,7 +111,7 @@ func TestEnclaveOpenError(t *testing.T) {
 	err := s.Link(map[string]telegraf.ResolveFunc{})
 	require.ErrorContains(t, err, "opening enclave failed")
 
-	s.unlinked = []string{}
+	s.unlinked = make([]string, 0)
 	_, err = s.Get()
 	require.ErrorContains(t, err, "opening enclave failed")
 }

filter/filter_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 func TestCompile(t *testing.T) {
-	f, err := Compile([]string{})
+	f, err := Compile(nil)
 	require.NoError(t, err)
 	require.Nil(t, f)
 
@@ -50,10 +50,10 @@ func TestCompile(t *testing.T) {
 }
 
 func TestIncludeExclude(t *testing.T) {
-	tags := []string{}
 	labels := []string{"best", "com_influxdata", "timeseries", "com_influxdata_telegraf", "ever"}
+	tags := make([]string, 0, len(labels))
 
-	filter, err := NewIncludeExcludeFilter([]string{}, []string{"com_influx*"})
+	filter, err := NewIncludeExcludeFilter(nil, []string{"com_influx*"})
 	if err != nil {
 		t.Fatalf("Failed to create include/exclude filter - %v", err)
 	}

internal/process/process.go

@@ -45,7 +45,7 @@ func New(command []string, envs []string) (*Process, error) {
 	p := &Process{
 		RestartDelay: 5 * time.Second,
 		name:         command[0],
-		args:         []string{},
+		args:         make([]string, 0),
 		envs:         envs,
 	}
 

internal/snmp/field_test.go

@@ -181,7 +181,7 @@ func TestConvertHextoint(t *testing.T) {
 		{
 			name:       "big endian invalid",
 			conversion: "hextoint:BigEndian:invalid",
-			ent:        gosnmp.SnmpPDU{Type: gosnmp.OctetString, Value: []uint8{}},
+			ent:        gosnmp.SnmpPDU{Type: gosnmp.OctetString, Value: make([]uint8, 0)},
 			errmsg:     "invalid bit value",
 		},
 		{
@@ -223,13 +223,13 @@ func TestConvertHextoint(t *testing.T) {
 		{
 			name:       "little endian invalid",
 			conversion: "hextoint:LittleEndian:invalid",
-			ent:        gosnmp.SnmpPDU{Type: gosnmp.OctetString, Value: []byte{}},
+			ent:        gosnmp.SnmpPDU{Type: gosnmp.OctetString, Value: make([]byte, 0)},
 			errmsg:     "invalid bit value",
 		},
 		{
 			name:       "invalid",
 			conversion: "hextoint:invalid:uint64",
-			ent:        gosnmp.SnmpPDU{Type: gosnmp.OctetString, Value: []byte{}},
+			ent:        gosnmp.SnmpPDU{Type: gosnmp.OctetString, Value: make([]byte, 0)},
 			errmsg:     "invalid Endian value",
 		},
 	}

internal/snmp/mib_loader.go

@@ -92,8 +92,8 @@ func LoadMibsFromPath(paths []string, log telegraf.Logger, loader MibLoader) err
 // should walk the paths given and find all folders
 func walkPaths(paths []string, log telegraf.Logger) ([]string, error) {
 	once.Do(gosmi.Init)
-	folders := []string{}
 
+	folders := make([]string, 0)
 	for _, mibPath := range paths {
 		// Check if we loaded that path already and skip it if so
 		m.Lock()

internal/snmp/translator_netsnmp_mocks_test.go

@@ -28,7 +28,7 @@ func TestMockExecCommand(_ *testing.T) {
 	var cmd []string //nolint:prealloc // Pre-allocated this slice would break the algorithm
 	for _, arg := range os.Args {
 		if arg == "--" {
-			cmd = []string{}
+			cmd = make([]string, 0)
 			continue
 		}
 		if cmd == nil {

metric/series_grouper.go

@@ -23,7 +23,7 @@ import (
 func NewSeriesGrouper() *SeriesGrouper {
 	return &SeriesGrouper{
 		metrics:  make(map[uint64]telegraf.Metric),
-		ordered:  []telegraf.Metric{},
+		ordered:  make([]telegraf.Metric, 0),
 		hashSeed: maphash.MakeSeed(),
 	}
 }

models/buffer_disk.go

@@ -127,7 +127,7 @@ func (b *DiskBuffer) Batch(batchSize int) []telegraf.Metric {
 
 	if b.length() == 0 {
 		// no metrics in the wal file, so return an empty array
-		return []telegraf.Metric{}
+		return make([]telegraf.Metric, 0)
 	}
 	b.batchFirst = b.readIndex()
 	var metrics []telegraf.Metric

models/filter.go

@@ -206,7 +206,7 @@ func (f *Filter) shouldTagsPass(tags []*telegraf.Tag) bool {
 
 // filterFields removes fields according to fieldinclude/fieldexclude.
 func (f *Filter) filterFields(metric telegraf.Metric) {
-	filterKeys := []string{}
+	filterKeys := make([]string, 0, len(metric.FieldList()))
 	for _, field := range metric.FieldList() {
 		if !ShouldPassFilters(f.fieldIncludeFilter, f.fieldExcludeFilter, field.Key) {
 			filterKeys = append(filterKeys, field.Key)
@@ -220,7 +220,7 @@ func (f *Filter) filterFields(metric telegraf.Metric) {
 
 // filterTags removes tags according to taginclude/tagexclude.
 func (f *Filter) filterTags(metric telegraf.Metric) {
-	filterKeys := []string{}
+	filterKeys := make([]string, 0, len(metric.TagList()))
 	for _, tag := range metric.TagList() {
 		if !ShouldPassFilters(f.tagIncludeFilter, f.tagExcludeFilter, tag.Key) {
 			filterKeys = append(filterKeys, tag.Key)

models/running_output_test.go

@@ -777,10 +777,6 @@ func (m *mockOutput) Write(metrics []telegraf.Metric) error {
 		return errors.New("failed write")
 	}
 
-	if m.metrics == nil {
-		m.metrics = []telegraf.Metric{}
-	}
-
 	m.metrics = append(m.metrics, metrics...)
 	return nil
 }

plugins/aggregators/basicstats/basicstats_test.go

@@ -718,7 +718,7 @@ func TestBasicStatsWithAllStats(t *testing.T) {
 // Test that if an empty array is passed, no points are pushed
 func TestBasicStatsWithNoStats(t *testing.T) {
 	aggregator := NewBasicStats()
-	aggregator.Stats = []string{}
+	aggregator.Stats = make([]string, 0)
 	aggregator.Log = testutil.Logger{}
 	aggregator.initConfiguredStats()
 

plugins/aggregators/histogram/histogram.go

@@ -139,9 +139,8 @@ func (h *HistogramAggregator) Add(in telegraf.Metric) {
 
 // Push returns histogram values for metrics
 func (h *HistogramAggregator) Push(acc telegraf.Accumulator) {
-	metricsWithGroupedFields := []groupedByCountFields{}
 	now := timeNow()
-
+	metricsWithGroupedFields := make([]groupedByCountFields, 0)
 	for id, aggregate := range h.cache {
 		if h.ExpirationInterval != 0 && now.After(aggregate.expireTime) {
 			delete(h.cache, id)

plugins/inputs/dmcache/dmcache_notlinux.go

@@ -11,5 +11,5 @@ func (*DMCache) Gather(_ telegraf.Accumulator) error {
 }
 
 func dmSetupStatus() ([]string, error) {
-	return []string{}, nil
+	return make([]string, 0), nil
 }

plugins/inputs/win_perf_counters/win_perf_counters_test.go

@@ -99,7 +99,7 @@ func (m *FakePerformanceQuery) ExpandWildCardPath(counterPath string) ([]string,
 	if e, ok := m.expandPaths[counterPath]; ok {
 		return e, nil
 	}
-	return []string{}, fmt.Errorf("in ExpandWildCardPath: invalid counter path: %q", counterPath)
+	return nil, fmt.Errorf("in ExpandWildCardPath: invalid counter path: %q", counterPath)
 }
 
 func (m *FakePerformanceQuery) GetFormattedCounterValueDouble(counterHandle pdhCounterHandle) (float64, error) {

plugins/inputs/win_services/win_services_integration_test.go

@@ -50,7 +50,7 @@ func TestEmptyListIntegration(t *testing.T) {
 	}()
 
 	winServices := &WinServices{
-		ServiceNames: []string{},
+		ServiceNames: make([]string, 0),
 	}
 
 	require.NoError(t, winServices.Init())

testutil/container.go

@@ -78,9 +78,7 @@ func (c *Container) Start() error {
 	}
 	c.container = cntnr
 
-	c.Logs = TestLogConsumer{
-		Msgs: []string{},
-	}
+	c.Logs = TestLogConsumer{}
 	c.container.FollowOutput(&c.Logs)
 	err = c.container.StartLogProducer(c.ctx)
 	if err != nil {

tools/readme_linter/main.go

@@ -97,7 +97,7 @@ func checkFile(filename string, pluginType plugin, sourceFlag bool) (bool, error
 	scanner := bufio.NewScanner(bytes.NewReader(md))
 	scanner.Split(bufio.ScanRunes)
 	offset := 0
-	newlineOffsets := []int{}
+	newlineOffsets := make([]int, 0)
 	for scanner.Scan() {
 		if scanner.Text() == "\n" {
 			newlineOffsets = append(newlineOffsets, offset)

tools/readme_linter/rules.go

@@ -92,7 +92,7 @@ func noLongLinesInParagraphs(threshold int) func(*T, ast.Node) error {
 	return func(t *T, root ast.Node) error {
 		// We're looking for long lines in paragraphs. Find paragraphs
 		// first, then which lines are in paragraphs
-		paraLines := []int{}
+		paraLines := make([]int, 0)
 		for n := root.FirstChild(); n != nil; n = n.NextSibling() {
 			var p *ast.Paragraph
 			var ok bool
@@ -108,7 +108,7 @@ func noLongLinesInParagraphs(threshold int) func(*T, ast.Node) error {
 		}
 
 		// Find long lines in the whole file
-		longLines := []int{}
+		longLines := make([]int, 0, len(t.newlineOffsets))
 		last := 0
 		for i, cur := range t.newlineOffsets {
 			length := cur - last - 1 // -1 to exclude the newline
@@ -121,7 +121,7 @@ func noLongLinesInParagraphs(threshold int) func(*T, ast.Node) error {
 		// Merge both lists
 		p := 0
 		l := 0
-		bads := []int{}
+		bads := make([]int, 0, max(len(paraLines), len(longLines)))
 		for p < len(paraLines) && l < len(longLines) {
 			long := longLines[l]
 			para := paraLines[p]