chore: Upgrade golangci-lint to v2

- Migrate the configuration file
- Update the tooling version and CI
- Apply auto-fixes

Signed-off-by: Kemal Akkoyun <[email protected]>

Author: kakkoyun

.github/workflows/golangci-lint.yml

@@ -33,7 +33,7 @@ jobs:
         run: sudo apt-get update && sudo apt-get -y install libsnmp-dev
         if: github.repository == 'prometheus/snmp_exporter'
       - name: Lint
-        uses: golangci/golangci-lint-action@55c2c1448f86e01eaae002a5a3a9624417608d84 # v6.5.2
+        uses: golangci/golangci-lint-action@1481404843c368bc19ca9406f87d6e0fc97bdcfd # v7.0.0
         with:
           args: --verbose
-          version: v1.64.6
+          version: v2.0.2

.golangci.yml

@@ -1,46 +1,60 @@
-issues:
-  max-issues-per-linter: 0
-  max-same-issues: 0
+version: "2"
 linters:
   enable:
-    - errcheck
     - errorlint
-    - gofumpt
-    - goimports
-    - gosimple
-    - govet
-    - ineffassign
     - misspell
     - perfsprint
     - revive
-    - staticcheck
     - testifylint
-    - unused
-linters-settings:
-  goimports:
-    local-prefixes: github.com/prometheus/common
-  perfsprint:
-    # Optimizes even if it requires an int or uint type cast.
-    int-conversion: true
-    # Optimizes into `err.Error()` even if it is only equivalent for non-nil errors.
-    err-error: true
-    # Optimizes `fmt.Errorf`.
-    errorf: true
-    # Optimizes `fmt.Sprintf` with only one argument.
-    sprintf1: true
-    # Optimizes into strings concatenation.
-    strconcat: false
-  revive:
-    rules:
-      # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#unused-parameter
-      - name: unused-parameter
-        severity: warning
-        disabled: true
-  testifylint:
-    disable:
-      - go-require
-    enable-all: true
-    formatter:
-      require-f-funcs: true
-run:
-  timeout: 5m
+  settings:
+    perfsprint:
+      # Optimizes even if it requires an int or uint type cast.
+      int-conversion: true
+      # Optimizes into `err.Error()` even if it is only equivalent for non-nil errors.
+      err-error: true
+      # Optimizes `fmt.Errorf`.
+      errorf: true
+      # Optimizes `fmt.Sprintf` with only one argument.
+      sprintf1: true
+      # Optimizes into strings concatenation.
+      strconcat: false
+    revive:
+      rules:
+        # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#unused-parameter
+        - name: unused-parameter
+          severity: warning
+          disabled: true
+    testifylint:
+      enable-all: true
+      disable:
+        - go-require
+      formatter:
+        require-f-funcs: true
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
+issues:
+  max-issues-per-linter: 0
+  max-same-issues: 0
+formatters:
+  enable:
+    - gofumpt
+    - goimports
+  settings:
+    goimports:
+      local-prefixes:
+        - github.com/prometheus/common
+  exclusions:
+    generated: lax
+    paths:
+      - third_party$
+      - builtin$
+      - examples$

Makefile.common

@@ -61,7 +61,7 @@ PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_
 SKIP_GOLANGCI_LINT :=
 GOLANGCI_LINT :=
 GOLANGCI_LINT_OPTS ?=
-GOLANGCI_LINT_VERSION ?= v1.64.6
+GOLANGCI_LINT_VERSION ?= v2.0.2
 # golangci-lint only supports linux, darwin and windows platforms on i386/amd64/arm64.
 # windows isn't included here because of the path separator being different.
 ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))

config/http_config.go

@@ -225,7 +225,7 @@ func (u *URL) UnmarshalJSON(data []byte) error {
 // MarshalJSON implements the json.Marshaler interface for URL.
 func (u URL) MarshalJSON() ([]byte, error) {
 	if u.URL != nil {
-		return json.Marshal(u.URL.String())
+		return json.Marshal(u.String())
 	}
 	return []byte("null"), nil
 }
@@ -251,7 +251,7 @@ func (o *OAuth2) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if err := unmarshal((*plain)(o)); err != nil {
 		return err
 	}
-	return o.ProxyConfig.Validate()
+	return o.Validate()
 }
 
 // UnmarshalJSON implements the json.Marshaler interface for URL.
@@ -260,7 +260,7 @@ func (o *OAuth2) UnmarshalJSON(data []byte) error {
 	if err := json.Unmarshal(data, (*plain)(o)); err != nil {
 		return err
 	}
-	return o.ProxyConfig.Validate()
+	return o.Validate()
 }
 
 // SetDirectory joins any relative file paths with dir.
@@ -604,8 +604,8 @@ func NewRoundTripperFromConfigWithContext(ctx context.Context, cfg HTTPClientCon
 		// The only timeout we care about is the configured scrape timeout.
 		// It is applied on request. So we leave out any timings here.
 		var rt http.RoundTripper = &http.Transport{
-			Proxy:                 cfg.ProxyConfig.Proxy(),
-			ProxyConnectHeader:    cfg.ProxyConfig.GetProxyConnectHeader(),
+			Proxy:                 cfg.Proxy(),
+			ProxyConnectHeader:    cfg.GetProxyConnectHeader(),
 			MaxIdleConns:          20000,
 			MaxIdleConnsPerHost:   1000, // see https://github.com/golang/go/issues/13801
 			DisableKeepAlives:     !opts.keepAlivesEnabled,
@@ -914,8 +914,8 @@ func (rt *oauth2RoundTripper) newOauth2TokenSource(req *http.Request, secret str
 	tlsTransport := func(tlsConfig *tls.Config) (http.RoundTripper, error) {
 		return &http.Transport{
 			TLSClientConfig:       tlsConfig,
-			Proxy:                 rt.config.ProxyConfig.Proxy(),
-			ProxyConnectHeader:    rt.config.ProxyConfig.GetProxyConnectHeader(),
+			Proxy:                 rt.config.Proxy(),
+			ProxyConnectHeader:    rt.config.GetProxyConnectHeader(),
 			DisableKeepAlives:     !rt.opts.keepAlivesEnabled,
 			MaxIdleConns:          20,
 			MaxIdleConnsPerHost:   1, // see https://github.com/golang/go/issues/13801
@@ -1508,7 +1508,7 @@ func (c *ProxyConfig) Proxy() (fn func(*http.Request) (*url.URL, error)) {
 		}
 		return
 	}
-	if c.ProxyURL.URL != nil && c.ProxyURL.URL.String() != "" {
+	if c.ProxyURL.URL != nil && c.ProxyURL.String() != "" {
 		if c.NoProxy == "" {
 			c.proxyFunc = http.ProxyURL(c.ProxyURL.URL)
 			return

expfmt/text_parse.go

@@ -345,8 +345,8 @@ func (p *TextParser) startLabelName() stateFn {
 	}
 	// Special summary/histogram treatment. Don't add 'quantile' and 'le'
 	// labels to 'real' labels.
-	if !(p.currentMF.GetType() == dto.MetricType_SUMMARY && p.currentLabelPair.GetName() == model.QuantileLabel) &&
-		!(p.currentMF.GetType() == dto.MetricType_HISTOGRAM && p.currentLabelPair.GetName() == model.BucketLabel) {
+	if (p.currentMF.GetType() != dto.MetricType_SUMMARY || p.currentLabelPair.GetName() != model.QuantileLabel) &&
+		(p.currentMF.GetType() != dto.MetricType_HISTOGRAM || p.currentLabelPair.GetName() != model.BucketLabel) {
 		p.currentLabelPairs = append(p.currentLabelPairs, p.currentLabelPair)
 	}
 	// Check for duplicate label names.

model/labels.go

@@ -122,7 +122,8 @@ func (ln LabelName) IsValidLegacy() bool {
 		return false
 	}
 	for i, b := range ln {
-		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) {
+		// TODO: Apply De Morgan's law. Make sure there are tests for this.
+		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) { //nolint:staticcheck
 			return false
 		}
 	}

route/route_test.go

@@ -154,7 +154,7 @@ func TestInstrumentations(t *testing.T) {
 		r, err := http.NewRequest("GET", "http://localhost:9090/foo", nil)
 		require.NoErrorf(t, err, "Error building test request: %s", err)
 		c.router.ServeHTTP(nil, r)
-		require.Equalf(t, len(c.want), len(got), "Unexpected value: want %q, got %q", c.want, got)
+		require.Lenf(t, got, len(c.want), "Unexpected value: want %q, got %q", c.want, got)
 		for i, v := range c.want {
 			require.Equalf(t, v, got[i], "Unexpected value: want %q, got %q", c.want, got)
 		}