permanently enable the linters

.golangci.yml

@@ -1,5 +1,20 @@
-# Run only staticcheck for now. Additional linters will be enabled one-by-one.
 linters:
   enable:
-  - staticcheck
+    - deadcode
+    - depguard
+    - durationcheck
+    - errorlint
+    - exportloopref
+    - gofmt
+    - gosimple
+    - ineffassign
+    - misspell
+    - nolintlint
+    - predeclared
+    - staticcheck
+    - structcheck
+    - unconvert
+    - unused
+    - varcheck
+    - wastedassign
   disable-all: true

api/prometheus/v1/api_test.go

@@ -1024,7 +1024,7 @@ func TestAPIs(t *testing.T) {
 			reqMethod: "GET",
 			reqPath:   "/api/v1/metadata",
 			res: map[string][]Metadata{
-				"go_goroutines": []Metadata{
+				"go_goroutines": {
 					{
 						Type: "gauge",
 						Help: "Number of goroutines that currently exist.",
@@ -1455,9 +1455,13 @@ func TestAPIClientDo(t *testing.T) {
 				}
 
 				if test.expectedErr.Detail != "" {
-					apiErr := err.(*Error)
-					if apiErr.Detail != test.expectedErr.Detail {
-						t.Fatalf("expected error detail :%v, but got:%v", apiErr.Detail, test.expectedErr.Detail)
+					apiErr := &Error{}
+					if errors.As(err, &apiErr) {
+						if apiErr.Detail != test.expectedErr.Detail {
+							t.Fatalf("expected error detail :%v, but got:%v", apiErr.Detail, test.expectedErr.Detail)
+						}
+					} else {
+						t.Fatalf("expected v1.Error instance, but got:%T", err)
 					}
 				}
 

prometheus/counter_test.go

@@ -231,7 +231,7 @@ func TestCounterExemplar(t *testing.T) {
 	}
 	expectedExemplar := &dto.Exemplar{
 		Label: []*dto.LabelPair{
-			&dto.LabelPair{Name: proto.String("foo"), Value: proto.String("bar")},
+			{Name: proto.String("foo"), Value: proto.String("bar")},
 		},
 		Value:     proto.Float64(42),
 		Timestamp: ts,

prometheus/internal/difflib.go

@@ -163,12 +163,12 @@ func (m *SequenceMatcher) chainB() {
 	m.bJunk = map[string]struct{}{}
 	if m.IsJunk != nil {
 		junk := m.bJunk
-		for s, _ := range b2j {
+		for s := range b2j {
 			if m.IsJunk(s) {
 				junk[s] = struct{}{}
 			}
 		}
-		for s, _ := range junk {
+		for s := range junk {
 			delete(b2j, s)
 		}
 	}
@@ -183,7 +183,7 @@ func (m *SequenceMatcher) chainB() {
 				popular[s] = struct{}{}
 			}
 		}
-		for s, _ := range popular {
+		for s := range popular {
 			delete(b2j, s)
 		}
 	}

prometheus/internal/difflib_test.go

@@ -185,14 +185,14 @@ func TestWithAsciiBJunk(t *testing.T) {
 
 	sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
 		splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
-	assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}})
+	assertEqual(t, sm.bJunk, map[string]struct{}{" ": {}})
 
 	isJunk = func(s string) bool {
 		return s == " " || s == "b"
 	}
 	sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
 		splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
-	assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}, "b": struct{}{}})
+	assertEqual(t, sm.bJunk, map[string]struct{}{" ": {}, "b": {}})
 }
 
 func TestSFBugsRatioForNullSeqn(t *testing.T) {

prometheus/process_collector.go

@@ -154,11 +154,11 @@ func NewPidFileFn(pidFilePath string) func() (int, error) {
 	return func() (int, error) {
 		content, err := ioutil.ReadFile(pidFilePath)
 		if err != nil {
-			return 0, fmt.Errorf("can't read pid file %q: %+v", pidFilePath, err)
+			return 0, fmt.Errorf("can't read pid file %q: %w", pidFilePath, err)
 		}
 		pid, err := strconv.Atoi(strings.TrimSpace(string(content)))
 		if err != nil {
-			return 0, fmt.Errorf("can't parse pid file %q: %+v", pidFilePath, err)
+			return 0, fmt.Errorf("can't parse pid file %q: %w", pidFilePath, err)
 		}
 
 		return pid, nil

prometheus/registry.go

@@ -15,6 +15,7 @@ package prometheus
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -725,7 +726,8 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 	for i, g := range gs {
 		mfs, err := g.Gather()
 		if err != nil {
-			if multiErr, ok := err.(MultiError); ok {
+			multiErr := MultiError{}
+			if errors.As(err, &multiErr) {
 				for _, err := range multiErr {
 					errs = append(errs, fmt.Errorf("[from Gatherer #%d] %w", i+1, err))
 				}

prometheus/registry_test.go

@@ -1243,7 +1243,7 @@ func TestNewMultiTRegistry(t *testing.T) {
 	t.Run("two registries, one with error", func(t *testing.T) {
 		m := prometheus.NewMultiTRegistry(prometheus.ToTransactionalGatherer(reg), treg)
 		ret, done, err := m.Gather()
-		if err != treg.err {
+		if !errors.Is(err, treg.err) {
 			t.Error("unexpected error:", err)
 		}
 		done()