chore: Apply simple linter fixes.

Use `_` for unused variables.

.github/workflows/golangci-lint.yml

@@ -21,8 +21,12 @@ jobs:
       - uses: actions/checkout@v4
       - uses: golangci/golangci-lint-action@v3
         with:
-          # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
+          # Required: the version of golangci-lint is required and must be
+          # specified without patch version: we always use the latest patch
+          # version.
           version: v1.52
 
-          # Optional: show only new issues if it's a pull request. The default value is `false`.
+          # Optional: show only new issues if it's a pull request. The default
+          # value is `false`.  Be careful upgrading because this won't show
+          # existing lints.
           only-new-issues: true

Makefile

@@ -104,7 +104,7 @@ veryclean: clean depclean
 
 # This version should match the one in .github/workflows/golangci-lint.yml
 GOLANGCILINT_VERSION=$(shell grep 'version: v' .github/workflows/golangci-lint.yml | cut -f2 -d: | tr -d ' ')
-#GOLANGCILINT_VERSION=v1.52
+
 # lint
 .PHONY: lint
 lint:  $(GOFILES) $(GOGENFILES) $(GOTESTFILES)

internal/exporter/graphite.go

@@ -53,7 +53,7 @@ func (e *Exporter) HandleGraphite(w http.ResponseWriter, r *http.Request) {
 
 // metricToGraphite encodes a metric in the graphite text protocol format.  The
 // metric lock is held before entering this function.
-func metricToGraphite(hostname string, m *metrics.Metric, l *metrics.LabelSet, _ time.Duration) string {
+func metricToGraphite(_ string, m *metrics.Metric, l *metrics.LabelSet, _ time.Duration) string {
 	var b strings.Builder
 	if m.Kind == metrics.Histogram && m.Type == metrics.Buckets {
 		d := m.LabelValues[0].Value

internal/exporter/json.go

@@ -14,7 +14,7 @@ import (
 var exportJSONErrors = expvar.NewInt("exporter_json_errors")
 
 // HandleJSON exports the metrics in JSON format via HTTP.
-func (e *Exporter) HandleJSON(w http.ResponseWriter, r *http.Request) {
+func (e *Exporter) HandleJSON(w http.ResponseWriter, _ *http.Request) {
 	b, err := json.MarshalIndent(e.store, "", "  ")
 	if err != nil {
 		exportJSONErrors.Add(1)

internal/exporter/statsd.go

@@ -24,7 +24,7 @@ var (
 
 // metricToStatsd encodes a metric in the statsd text protocol format.  The
 // metric lock is held before entering this function.
-func metricToStatsd(hostname string, m *metrics.Metric, l *metrics.LabelSet, _ time.Duration) string {
+func metricToStatsd(_ string, m *metrics.Metric, l *metrics.LabelSet, _ time.Duration) string {
 	var t string
 	switch m.Kind {
 	case metrics.Counter:

internal/metrics/datum/datum.go

@@ -94,7 +94,7 @@ func MakeString(v string, ts time.Time) Datum {
 
 // MakeBuckets creates a new bucket datum with the provided list of ranges and
 // timestamp.  If no +inf bucket is provided, one is created.
-func MakeBuckets(buckets []Range, ts time.Time) Datum {
+func MakeBuckets(buckets []Range, _ time.Time) Datum {
 	d := &Buckets{}
 	seenInf := false
 	highest := 0.0

internal/metrics/metric.go

@@ -64,7 +64,7 @@ func (m Kind) String() string {
 }
 
 // Generate implements the quick.Generator interface for Kind.
-func (Kind) Generate(rand *rand.Rand, size int) reflect.Value {
+func (Kind) Generate(rand *rand.Rand, _ int) reflect.Value {
 	return reflect.ValueOf(Kind(rand.Intn(int(endKind))))
 }
 

internal/metrics/type.go

@@ -39,6 +39,6 @@ func (t Type) String() string {
 }
 
 // Generate implements the quick.Generator interface for Type.
-func (Type) Generate(rand *rand.Rand, size int) reflect.Value {
+func (Type) Generate(rand *rand.Rand, _ int) reflect.Value {
 	return reflect.ValueOf(Type(rand.Intn(int(endType))))
 }

internal/mtail/httpstatus.go

@@ -31,7 +31,7 @@ const statusTemplateEnd = `
 
 // ServeHTTP satisfies the http.Handler interface, and is used to serve the
 // root page of mtail for online status reporting.
-func (m *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+func (m *Server) ServeHTTP(w http.ResponseWriter, _ *http.Request) {
 	t, err := template.New("status").Parse(statusTemplate)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -77,7 +77,7 @@ func (m *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 // FaviconHandler is used to serve up the favicon.ico for mtail's http server.
-func FaviconHandler(w http.ResponseWriter, r *http.Request) {
+func FaviconHandler(w http.ResponseWriter, _ *http.Request) {
 	w.Header().Set("Content-Type", "image/x-icon")
 	w.Header().Set("Cache-Control", "public, max-age=7776000")
 	if _, err := w.Write(logoFavicon); err != nil {

internal/mtail/options.go

@@ -261,7 +261,7 @@ var LogRuntimeErrors = &niladicOption{
 // JaegerReporter creates a new jaeger reporter that sends to the given Jaeger endpoint address.
 type JaegerReporter string
 
-func (opt JaegerReporter) apply(m *Server) error {
+func (opt JaegerReporter) apply(_ *Server) error {
 	je, err := jaeger.NewExporter(jaeger.Options{
 		CollectorEndpoint: string(opt),
 		Process: jaeger.Process{

internal/runtime/compiler/symbol/symtab_test.go

@@ -25,7 +25,7 @@ func TestInsertLookup(t *testing.T) {
 }
 
 // Generate implements the quick.Generator interface for SymbolKind.
-func (Kind) Generate(rand *rand.Rand, size int) reflect.Value {
+func (Kind) Generate(rand *rand.Rand, _ int) reflect.Value {
 	return reflect.ValueOf(Kind(rand.Intn(int(endSymbol))))
 }
 

internal/runtime/vm/vm.go

@@ -959,7 +959,7 @@ func (v *VM) execute(t *thread, i code.Instr) {
 
 // ProcessLogLine handles the incoming lines by running a fetch-execute cycle
 // on the VM bytecode with the line as input to the program, until termination.
-func (v *VM) ProcessLogLine(ctx context.Context, line *logline.LogLine) {
+func (v *VM) ProcessLogLine(_ context.Context, line *logline.LogLine) {
 	start := time.Now()
 	defer func() {
 		LineProcessingDurations.WithLabelValues(v.name).Observe(time.Since(start).Seconds())

internal/tailer/logstream/pipestream.go

@@ -41,7 +41,7 @@ func (ps *pipeStream) LastReadTime() time.Time {
 	return ps.lastReadTime
 }
 
-func (ps *pipeStream) stream(ctx context.Context, wg *sync.WaitGroup, waker waker.Waker, fi os.FileInfo) error {
+func (ps *pipeStream) stream(ctx context.Context, wg *sync.WaitGroup, waker waker.Waker, _ os.FileInfo) error {
 	// Open in nonblocking mode because the write end of the pipe may not have started yet.
 	fd, err := os.OpenFile(ps.pathname, os.O_RDONLY|syscall.O_NONBLOCK, 0o600)
 	if err != nil {