permanently enable the linters

Signed-off-by: Christoph Mewes <christoph@kubermatic.com>

.golangci.yml

@@ -8,10 +8,26 @@ output:
 
 linters:
   enable:
+    - deadcode
+    - depguard
+    - durationcheck
+    - errorlint
+    - exportloopref
+    - gofmt
     - gofumpt
     - goimports
-    - revive
+    - gosimple
+    - ineffassign
     - misspell
+    - nolintlint
+    - predeclared
+    - revive
+    - staticcheck
+    - structcheck
+    - unconvert
+    - unused
+    - varcheck
+    - wastedassign
 
 issues:
   max-same-issues: 0

api/prometheus/v1/api_test.go

@@ -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/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/promhttp/instrument_server_test.go

@@ -145,7 +145,6 @@ func TestLabelCheck(t *testing.T) {
 				},
 				append(sc.varLabels, sc.curriedLabels...),
 			))
-			//nolint:typecheck // Ignore declared but unused error.
 			for _, l := range sc.curriedLabels {
 				c = c.MustCurryWith(prometheus.Labels{l: "dummy"})
 				o = o.MustCurryWith(prometheus.Labels{l: "dummy"})

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

@@ -1242,7 +1242,7 @@ 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()