refactor: bump golangci-lint to 2.6.2

.github/workflows/presubmit.yml

@@ -43,7 +43,7 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v7
         with:
-          version: v2.0.2
+          version: v2.6.2
           skip-cache: true
           args: --timeout=5m --verbose
   validate:

.golangci.yml

@@ -44,6 +44,7 @@ linters:
     - nilnil
     - nlreturn
     - noctx
+    - noinlineerr
     # TODO(bwplotka): Remove once https://github.com/golangci/golangci-lint/issues/3228 is fixed.
     - nolintlint
     - nonamedreturns
@@ -61,7 +62,36 @@ linters:
     - wastedassign
     - wrapcheck
     - wsl
+    - wsl_v5
   settings:
+    errcheck:
+      # Report about not checking of errors in type assertions: `a := b.(MyStruct)`.
+      # Such cases aren't reported by default.
+      # Default: false
+      check-type-assertions: false
+      # report about assignment of errors to blank identifier: `num, _ := strconv.Atoi(numStr)`.
+      # Such cases aren't reported by default.
+      # Default: false
+      check-blank: false
+      # To disable the errcheck built-in exclude list.
+      # See `-excludeonly` option in https://github.com/kisielk/errcheck#excluding-functions for details.
+      # Default: false
+      disable-default-exclusions: false
+      # List of functions to exclude from checking, where each entry is a single function to exclude.
+      # See https://github.com/kisielk/errcheck#excluding-functions for details.
+      exclude-functions:
+        - fmt.Fprint
+        - fmt.Fprintf
+        - fmt.Fprintln
+        - fmt.Print
+        - fmt.Printf
+        - fmt.Println
+        - io/ioutil.ReadFile
+        - io.Copy(*bytes.Buffer)
+        - io.Copy(os.Stdout)
+      # Display function signature instead of selector.
+      # Default: false
+      verbose: true
     importas:
       alias:
         - pkg: k8s.io/api/apps/v1
@@ -167,11 +197,17 @@ linters:
           severity: warning
           disabled: true
         - name: unhandled-error
-          arguments:
-            - fmt.Printf
-            - myFunction
           severity: warning
-          disabled: true
+          disabled: false
+          exclude: [""]
+          arguments:
+            - "fmt.Fprint"
+            - "fmt.Fprintf"
+            - "fmt.Fprintln"
+            - "fmt.Print"
+            - "fmt.Printf"
+            - "fmt.Println"
+            - "strings.Builder.WriteByte"
         - name: unused-receiver
           arguments:
             - allowRegex: ^_

cmd/datasource-syncer/main.go

@@ -135,8 +135,7 @@ func main() {
 
 	dsSuccessfullyUpdated := []string{}
 	dsErrors := []string{}
-	datasourceUIDs := strings.Split(*datasourceUIDList, ",")
-	for _, datasourceUID := range datasourceUIDs {
+	for datasourceUID := range strings.SplitSeq(*datasourceUIDList, ",") {
 		datasourceUID = strings.TrimSpace(datasourceUID)
 		if datasourceUID == "" {
 			continue
@@ -290,7 +289,7 @@ func buildUpdateDataSourceRequest(dataSource grafana.DataSource, token string) (
 	}
 	authHeaderValue := fmt.Sprintf("%s%d", httpHeaderValue, x)
 	if dataSource.SecureJSONData == nil {
-		dataSource.SecureJSONData = map[string]interface{}{}
+		dataSource.SecureJSONData = map[string]any{}
 	}
 	// Add token to SecureJSONData e.g. httpHeaderValue1: Bearer 123.
 	dataSource.SecureJSONData[authHeaderValue] = fmt.Sprintf("Bearer %s", token)

cmd/datasource-syncer/main_test.go

@@ -36,20 +36,20 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			name: "OK",
 			input: grafana.DataSource{
 				Type:     "prometheus",
-				JSONData: map[string]interface{}{},
+				JSONData: map[string]any{},
 			},
 			want: grafana.DataSource{
 				URL:  "https://monitoring.googleapis.com/v1/projects/test/location/global/prometheus/",
 				Type: "prometheus",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1":   "Authorization",
 					"httpMethod":        "GET",
 					"prometheusType":    "Prometheus",
 					"prometheusVersion": "2.40.0",
 					"queryTimeout":      "2m",
 					"timeout":           "120",
 				},
-				SecureJSONData: map[string]interface{}{
+				SecureJSONData: map[string]any{
 					"httpHeaderValue1": "Bearer 12345",
 				},
 			},
@@ -59,15 +59,15 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			input: grafana.DataSource{
 				URL:  "http://localhost:9090",
 				Type: "prometheus",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1": "X-Custom-Header",
 					"httpHeaderName2": "X-Custom-Header2",
 				},
 			},
 			want: grafana.DataSource{
 				URL:  "https://monitoring.googleapis.com/v1/projects/test/location/global/prometheus/",
 				Type: "prometheus",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1":   "X-Custom-Header",
 					"httpHeaderName2":   "X-Custom-Header2",
 					"httpHeaderName3":   "Authorization",
@@ -77,7 +77,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 					"queryTimeout":      "2m",
 					"timeout":           "120",
 				},
-				SecureJSONData: map[string]interface{}{
+				SecureJSONData: map[string]any{
 					"httpHeaderValue3": "Bearer 12345",
 				},
 			},
@@ -87,7 +87,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			input: grafana.DataSource{
 				URL:  "http://localhost:9090",
 				Type: "prometheus",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1":   "X-Custom-Header",
 					"httpHeaderName2":   "Authorization",
 					"httpHeaderName3":   "X-Custom-Header3",
@@ -99,7 +99,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			want: grafana.DataSource{
 				URL:  "https://monitoring.googleapis.com/v1/projects/test/location/global/prometheus/",
 				Type: "prometheus",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1":   "X-Custom-Header",
 					"httpHeaderName2":   "Authorization",
 					"httpHeaderName3":   "X-Custom-Header3",
@@ -109,7 +109,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 					"queryTimeout":      "2m",
 					"timeout":           "120",
 				},
-				SecureJSONData: map[string]interface{}{
+				SecureJSONData: map[string]any{
 					"httpHeaderValue2": "Bearer 12345",
 				},
 			},
@@ -119,7 +119,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			input: grafana.DataSource{
 				Type: "prometheus",
 				URL:  "http://localhost:9090",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1":   "X-Custom-Header",
 					"httpHeaderName2":   "X-Custom-Header2",
 					"httpHeaderName3":   "Authorization",
@@ -131,7 +131,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			want: grafana.DataSource{
 				URL:  "https://monitoring.googleapis.com/v1/projects/test/location/global/prometheus/",
 				Type: "prometheus",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1":   "X-Custom-Header",
 					"httpHeaderName2":   "X-Custom-Header2",
 					"httpHeaderName3":   "Authorization",
@@ -141,7 +141,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 					"queryTimeout":      "2m",
 					"timeout":           "120",
 				},
-				SecureJSONData: map[string]interface{}{
+				SecureJSONData: map[string]any{
 					"httpHeaderValue3": "Bearer 12345",
 				},
 			},
@@ -151,7 +151,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			input: grafana.DataSource{
 				Type: "prometheus",
 				URL:  "http://localhost:9090",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"prometheusType":    "Prometheus",
 					"prometheusVersion": "2.42.0",
 					"queryTimeout":      "3m",
@@ -161,15 +161,15 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			want: grafana.DataSource{
 				URL:  "https://monitoring.googleapis.com/v1/projects/test/location/global/prometheus/",
 				Type: "prometheus",
-				JSONData: map[string]interface{}{
+				JSONData: map[string]any{
 					"httpHeaderName1":   "Authorization",
 					"httpMethod":        "GET",
 					"prometheusType":    "Prometheus",
 					"prometheusVersion": "2.42.0",
 					"queryTimeout":      "3m",
 					"timeout":           "160",
 				},
-				SecureJSONData: map[string]interface{}{
+				SecureJSONData: map[string]any{
 					"httpHeaderValue1": "Bearer 12345",
 				},
 			},
@@ -188,7 +188,7 @@ func TestBuildUpdateDataSourceRequest(t *testing.T) {
 			got, err := buildUpdateDataSourceRequest(tt.input, accessToken)
 			if tt.fail {
 				if err == nil {
-					t.Fatalf("unexpectedly succeeded")
+					t.Fatal("unexpectedly succeeded")
 				}
 				return
 			}

cmd/frontend/main.go

@@ -69,6 +69,7 @@ var (
 	targetURLStr = flag.String("query.target-url", fmt.Sprintf("https://monitoring.googleapis.com/v1/projects/%s/location/global/prometheus", projectIDVar),
 		fmt.Sprintf("The URL to forward authenticated requests to. (%s is replaced with the --query.project-id flag.)", projectIDVar))
 
+	//nolint:revive // Allow insecure http connection
 	ruleEndpointURLStrings = flag.String("rules.target-urls", "http://rule-evaluator.gmp-system.svc.cluster.local:19092", "Comma separated lists of URLs that support HTTP Prometheus Alert and Rules APIs (/api/v1/alerts, /api/v1/rules), e.g. GMP rule-evaluator. NOTE: Results are merged as-is, no sorting and deduplication is done.")
 
 	logLevel = flag.String("log.level", "info",
@@ -126,7 +127,7 @@ func main() {
 	}
 
 	var ruleEndpointURLs []url.URL
-	for _, ruleEndpointURLStr := range strings.Split(*ruleEndpointURLStrings, ",") {
+	for ruleEndpointURLStr := range strings.SplitSeq(*ruleEndpointURLStrings, ",") {
 		ruleEndpointURL, err := url.Parse(strings.TrimSpace(ruleEndpointURLStr))
 		if err != nil || ruleEndpointURL == nil {
 			_ = level.Error(logger).Log("msg", "parsing rule endpoint URL failed", "err", err, "url", strings.TrimSpace(ruleEndpointURLStr))
@@ -187,11 +188,11 @@ func main() {
 
 		http.HandleFunc("/-/healthy", func(w http.ResponseWriter, _ *http.Request) {
 			w.WriteHeader(http.StatusOK)
-			fmt.Fprintf(w, "Prometheus frontend is Healthy.\n")
+			fmt.Fprint(w, "Prometheus frontend is Healthy.\n")
 		})
 		http.HandleFunc("/-/ready", func(w http.ResponseWriter, _ *http.Request) {
 			w.WriteHeader(http.StatusOK)
-			fmt.Fprintf(w, "Prometheus frontend is Ready.\n")
+			fmt.Fprint(w, "Prometheus frontend is Ready.\n")
 		})
 
 		http.Handle("/", authenticate(ui.Handler(externalURL)))

cmd/rule-evaluator/internal/api.go

@@ -54,12 +54,12 @@ const (
 // https://prometheus.io/docs/prometheus/latest/querying/api/#format-overview
 // response is the prometheus-compatible response format.
 type response struct {
-	Status    status      `json:"status"`
-	Data      interface{} `json:"data,omitempty"`
-	ErrorType errorType   `json:"errorType,omitempty"`
-	Error     string      `json:"error,omitempty"`
-	Warnings  []string    `json:"warnings,omitempty"`
-	Infos     []string    `json:"infos,omitempty"`
+	Status    status    `json:"status"`
+	Data      any       `json:"data,omitempty"`
+	ErrorType errorType `json:"errorType,omitempty"`
+	Error     string    `json:"error,omitempty"`
+	Warnings  []string  `json:"warnings,omitempty"`
+	Infos     []string  `json:"infos,omitempty"`
 }
 
 // RuleRetriever provides a list of active rules.
@@ -102,7 +102,7 @@ func (api *API) writeResponse(w http.ResponseWriter, httpResponseCode int, endpo
 	}
 }
 
-func (api *API) writeSuccessResponse(w http.ResponseWriter, httpResponseCode int, endpointURI string, data interface{}) {
+func (api *API) writeSuccessResponse(w http.ResponseWriter, httpResponseCode int, endpointURI string, data any) {
 	api.writeResponse(w, httpResponseCode, endpointURI, response{
 		Status: statusSuccess,
 		Data:   data,

cmd/rule-evaluator/internal/rules_test.go

@@ -87,7 +87,6 @@ func TestAPI_HandleRulesEndpoint(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		tt := tt //nolint:copyloopvar // parallel test
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 
@@ -480,7 +479,6 @@ func TestAPI_groupToAPIGroup(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		tt := tt //nolint:copyloopvar // parallel test
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			api := &API{logger: log.NewNopLogger()}

cmd/rule-evaluator/main.go

@@ -342,7 +342,7 @@ func main() {
 		})
 		http.HandleFunc("/-/ready", func(w http.ResponseWriter, _ *http.Request) {
 			w.WriteHeader(http.StatusOK)
-			fmt.Fprintf(w, "rule-evaluator is Ready.\n")
+			fmt.Fprintln(w, "rule-evaluator is Ready.")
 		})
 		// https://prometheus.io/docs/prometheus/latest/querying/api/#runtime-information
 		// Useful for knowing whether a config reload was successful.
@@ -685,7 +685,7 @@ func (m *configMetrics) setFailure() {
 // reloadConfig applies the configuration files.
 func reloadConfig(filename string, logger log.Logger, metrics *configMetrics, rls ...reloader) (err error) {
 	start := time.Now()
-	timings := []interface{}{}
+	timings := []any{}
 	_ = level.Info(logger).Log("msg", "Loading configuration file", "filename", filename)
 
 	content, err := os.ReadFile(filename)
@@ -713,7 +713,7 @@ func reloadConfig(filename string, logger log.Logger, metrics *configMetrics, rl
 	}
 
 	metrics.setSuccess()
-	l := []interface{}{"msg", "Completed loading of configuration file", "filename", filename, "totalDuration", time.Since(start)}
+	l := []any{"msg", "Completed loading of configuration file", "filename", filename, "totalDuration", time.Since(start)}
 	_ = level.Info(logger).Log(append(l, timings...)...)
 	return nil
 }
@@ -853,6 +853,7 @@ func (s *queryStorage) Querier(mint, maxt int64) (storage.Querier, error) {
 type queryAccess struct {
 	// storage.LabelQuerier satisfies the interface. Calling related methods will result in panic.
 	storage.LabelQuerier
+
 	api   v1.API
 	mint  int64
 	maxt  int64