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

.gitignore

@@ -28,3 +28,4 @@ vendor/
 *.out
 
 .idea
+*.bck.*

.golangci.yml

@@ -1,86 +1,90 @@
----
-run:
-  timeout: 5m
-
-output:
-  sort-results: true
+version: "2"
+issues:
+  max-same-issues: 0
 
 linters:
   enable:
     - copyloopvar
     - depguard
     - durationcheck
     - errorlint
-    # The linter 'exportloopref' is deprecated (since v1.60.2) due to: Since Go1.22 (loopvar) this linter is no longer relevant. Replaced by copyloopvar.
-    # - exportloopref
-    - gofmt
-    - gofumpt
-    - goimports
-    - gosimple
-    - ineffassign
     - misspell
     - nolintlint
     - perfsprint
     - predeclared
     - revive
-    - staticcheck
     - unconvert
-    - unused
     - usestdlibvars
     - wastedassign
+  exclusions:
+      generated: lax
+      presets:
+        - comments
+        - common-false-positives
+        - legacy
+        - std-error-handling
+      rules:
+        - linters:
+            - errcheck
+            - govet
+            - structcheck
+            - nolintlint
+          path: _test.go
+      paths:
+        - ^.*\.(pb|y)\.go$
+        - third_party$
+        - builtin$
+        - examples$
+  settings:
+    depguard:
+      rules:
+        main:
+          deny:
+            - pkg: github.com/stretchr/testify/assert
+              desc: Use github.com/stretchr/testify/require instead of github.com/stretchr/testify/assert
+            - pkg: github.com/go-kit/kit/log
+              desc: Use github.com/go-kit/log instead of github.com/go-kit/kit/log
+            - pkg: io/ioutil
+              desc: Use corresponding 'os' or 'io' functions instead.
+    errcheck:
+      exclude-functions:
+        # The following 2 methods always return nil as the error
+        - (*github.com/cespare/xxhash/v2.Digest).Write
+        - (*github.com/cespare/xxhash/v2.Digest).WriteString
+        - (*bufio.Writer).WriteRune
+    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: true
+    revive:
+      rules:
 
-issues:
-  max-same-issues: 0
-  exclude-rules:
-    - path: _test.go
-      linters:
-        - errcheck
-        - govet
-        - structcheck
-  # The configuration option `run.skip-files` is deprecated, please use `issues.exclude-files`. 
-  exclude-files:
-    # Skip autogenerated files.
-    - ^.*\.(pb|y)\.go$
+        - name: unused-parameter
+          severity: warning
+          disabled: true
 
-linters-settings:
-  depguard:
-    rules:
-      main:
-        deny:
-        #- pkg: "sync/atomic"
-        #  desc: "Use go.uber.org/atomic instead of sync/atomic"
-        - pkg: "github.com/stretchr/testify/assert"
-          desc: "Use github.com/stretchr/testify/require instead of github.com/stretchr/testify/assert"
-        - pkg: "github.com/go-kit/kit/log"
-          desc: "Use github.com/go-kit/log instead of github.com/go-kit/kit/log"
-        - pkg: "io/ioutil"
-          desc: "Use corresponding 'os' or 'io' functions instead."
-        #- pkg: "regexp"
-        #  desc: "Use github.com/grafana/regexp instead of regexp"
-  errcheck:
-    exclude-functions:
-      # The following 2 methods always return nil as the error
-      - (*github.com/cespare/xxhash/v2.Digest).Write
-      - (*github.com/cespare/xxhash/v2.Digest).WriteString
-      - (*bufio.Writer).WriteRune
-  goimports:
-    local-prefixes: github.com/prometheus/client_golang
-  gofumpt:
-    extra-rules: true
-  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: true
-  revive:
-    rules:
-      # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#unused-parameter
-      - name: unused-parameter
-        severity: warning
-        disabled: true
+formatters:
+  enable:
+    - gofmt
+    - gofumpt
+    - goimports
+  settings:
+    gofumpt:
+      extra-rules: true
+    goimports:
+      local-prefixes:
+        - github.com/prometheus/client_golang
+  exclusions:
+    generated: lax
+    paths:
+      - ^.*\.(pb|y)\.go$
+      - 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))

prometheus/graphite/bridge.go

@@ -307,7 +307,8 @@ func replaceInvalidRune(c rune) rune {
 	if c == ' ' {
 		return '.'
 	}
-	if !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || c == ':' || c == '-' || (c >= '0' && c <= '9')) {
+	// TODO: Apply De Morgan's law to the condition. Make sure to test the condition first.
+	if !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || c == ':' || c == '-' || (c >= '0' && c <= '9')) { //nolint:staticcheck
 		return '_'
 	}
 	return c

prometheus/internal/difflib.go

@@ -453,7 +453,7 @@ func (m *SequenceMatcher) GetGroupedOpCodes(n int) [][]OpCode {
 		}
 		group = append(group, OpCode{c.Tag, i1, i2, j1, j2})
 	}
-	if len(group) > 0 && !(len(group) == 1 && group[0].Tag == 'e') {
+	if len(group) > 0 && (len(group) != 1 || group[0].Tag != 'e') {
 		groups = append(groups, group)
 	}
 	return groups
@@ -568,7 +568,7 @@ func WriteUnifiedDiff(writer io.Writer, diff UnifiedDiff) error {
 	buf := bufio.NewWriter(writer)
 	defer buf.Flush()
 	wf := func(format string, args ...interface{}) error {
-		_, err := buf.WriteString(fmt.Sprintf(format, args...))
+		_, err := fmt.Fprintf(buf, format, args)
 		return err
 	}
 	ws := func(s string) error {

prometheus/process_collector_darwin.go

@@ -25,9 +25,9 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-// notImplementedErr is returned by stub functions that replace cgo functions, when cgo
+// errNotImplemented is returned by stub functions that replace cgo functions, when cgo
 // isn't available.
-var notImplementedErr = errors.New("not implemented")
+var errNotImplemented = errors.New("not implemented")
 
 type memoryInfo struct {
 	vsize uint64 // Virtual memory size in bytes
@@ -101,7 +101,7 @@ func (c *processCollector) processCollect(ch chan<- Metric) {
 	if memInfo, err := getMemory(); err == nil {
 		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(memInfo.rss))
 		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(memInfo.vsize))
-	} else if !errors.Is(err, notImplementedErr) {
+	} else if !errors.Is(err, errNotImplemented) {
 		// Don't report an error when support is not compiled in.
 		c.reportError(ch, c.rss, err)
 		c.reportError(ch, c.vsize, err)

prometheus/process_collector_procfsenabled.go

@@ -66,11 +66,11 @@ func (c *processCollector) processCollect(ch chan<- Metric) {
 
 	if netstat, err := p.Netstat(); err == nil {
 		var inOctets, outOctets float64
-		if netstat.IpExt.InOctets != nil {
-			inOctets = *netstat.IpExt.InOctets
+		if netstat.InOctets != nil {
+			inOctets = *netstat.InOctets
 		}
-		if netstat.IpExt.OutOctets != nil {
-			outOctets = *netstat.IpExt.OutOctets
+		if netstat.OutOctets != nil {
+			outOctets = *netstat.OutOctets
 		}
 		ch <- MustNewConstMetric(c.inBytes, CounterValue, inOctets)
 		ch <- MustNewConstMetric(c.outBytes, CounterValue, outOctets)

prometheus/promhttp/instrument_server.go

@@ -392,7 +392,7 @@ func isLabelCurried(c prometheus.Collector, label string) bool {
 func labels(code, method bool, reqMethod string, status int, extraMethods ...string) prometheus.Labels {
 	labels := prometheus.Labels{}
 
-	if !(code || method) {
+	if !code && !method {
 		return labels
 	}
 

prometheus/vec.go

@@ -79,7 +79,7 @@ func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
 		return false
 	}
 
-	return m.metricMap.deleteByHashWithLabelValues(h, lvs, m.curry)
+	return m.deleteByHashWithLabelValues(h, lvs, m.curry)
 }
 
 // Delete deletes the metric where the variable labels are the same as those
@@ -101,7 +101,7 @@ func (m *MetricVec) Delete(labels Labels) bool {
 		return false
 	}
 
-	return m.metricMap.deleteByHashWithLabels(h, labels, m.curry)
+	return m.deleteByHashWithLabels(h, labels, m.curry)
 }
 
 // DeletePartialMatch deletes all metrics where the variable labels contain all of those
@@ -114,7 +114,7 @@ func (m *MetricVec) DeletePartialMatch(labels Labels) int {
 	labels, closer := constrainLabels(m.desc, labels)
 	defer closer()
 
-	return m.metricMap.deleteByLabels(labels, m.curry)
+	return m.deleteByLabels(labels, m.curry)
 }
 
 // Without explicit forwarding of Describe, Collect, Reset, those methods won't
@@ -216,7 +216,7 @@ func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
 		return nil, err
 	}
 
-	return m.metricMap.getOrCreateMetricWithLabelValues(h, lvs, m.curry), nil
+	return m.getOrCreateMetricWithLabelValues(h, lvs, m.curry), nil
 }
 
 // GetMetricWith returns the Metric for the given Labels map (the label names
@@ -244,7 +244,7 @@ func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
 		return nil, err
 	}
 
-	return m.metricMap.getOrCreateMetricWithLabels(h, labels, m.curry), nil
+	return m.getOrCreateMetricWithLabels(h, labels, m.curry), nil
 }
 
 func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) {