Enable more linters

.golangci.yml

@@ -9,9 +9,23 @@ linters:
     - staticcheck
     - whitespace
     - wrapcheck
+    - ineffassign
+    - unused
+    - unconvert
+    - bodyclose
+    - copyloopvar
+    - nilerr
+    - nilnil
+    - wastedassign
+    - maintidx
+    - nakedret
+    - predeclared
+    - gocritic
+    - prealloc
   exclusions:
     presets:
       - comments
 formatters:
   enable:
-    - gofmt
+    - gofumpt
+    - goimports

backend.go

@@ -19,9 +19,11 @@ func implementedBackends(m *Machine) []backend {
  * "auto" backend chooses them.
  */
 func BackendNames() []string {
-	names := []string{"auto"}
+	backends := implementedBackends(nil)
+	names := make([]string, 0, 1+len(backends))
+	names = append(names, "auto")
 
-	for _, backend := range implementedBackends(nil) {
+	for _, backend := range backends {
 		names = append(names, backend.Name())
 	}
 

backend_qemu.go

@@ -177,7 +177,7 @@ func (b qemuBackend) ModulePath() (string, error) {
 }
 
 func (b qemuBackend) UdevRules() []string {
-	udevRules := []string{}
+	udevRules := make([]string, 0, 2*len(b.machine.images))
 
 	// create symlink under /dev/disk/by-fakemachine-label/ for each virtual image
 	for i, img := range b.machine.images {
@@ -228,14 +228,16 @@ func (b qemuBackend) StartQemu(kvm bool) (bool, error) {
 	}
 	memory := fmt.Sprintf("%d", m.memory)
 	numcpus := fmt.Sprintf("%d", m.numcpus)
-	qemuargs := []string{qemuMachine.binary,
+	qemuargs := []string{
+		qemuMachine.binary,
 		"-smp", numcpus,
 		"-m", memory,
 		"-kernel", kernelPath,
 		"-initrd", m.initrdpath,
 		"-display", "none",
 		"-nic", "user,model=virtio-net-pci",
-		"-no-reboot"}
+		"-no-reboot",
+	}
 
 	if kvm {
 		qemuargs = append(qemuargs,
@@ -247,9 +249,11 @@ func (b qemuBackend) StartQemu(kvm bool) (bool, error) {
 
 	qemuargs = append(qemuargs, "-machine", qemuMachine.machine)
 	console := fmt.Sprintf("console=%s", qemuMachine.console)
-	kernelargs := []string{console, "panic=-1",
+	kernelargs := []string{
+		console, "panic=-1",
 		"plymouth.enable=0",
-		"systemd.unit=fakemachine.service"}
+		"systemd.unit=fakemachine.service",
+	}
 
 	if m.showBoot {
 		// Create a character device representing our stdio

cmd/fakemachine/main.go

@@ -1,15 +1,17 @@
 package main
 
 import (
-	"al.essio.dev/pkg/shellescape"
 	"errors"
 	"fmt"
-	"github.com/docker/go-units"
-	"github.com/go-debos/fakemachine"
-	"github.com/jessevdk/go-flags"
 	"os"
 	"runtime/debug"
 	"strings"
+
+	"al.essio.dev/pkg/shellescape"
+
+	"github.com/docker/go-units"
+	"github.com/go-debos/fakemachine"
+	"github.com/jessevdk/go-flags"
 )
 
 var Version string
@@ -28,8 +30,10 @@ type Options struct {
 	Version     bool              `long:"version" description:"Print fakemachine version"`
 }
 
-var options Options
-var parser = flags.NewParser(&options, flags.Default)
+var (
+	options Options
+	parser  = flags.NewParser(&options, flags.Default)
+)
 
 func determineVersionFromBuild() string {
 	info, ok := debug.ReadBuildInfo()
@@ -131,7 +135,7 @@ func SetupEnviron(m *fakemachine.Machine, options Options) {
 	// These are the environment variables that will be detected on the
 	// host and propagated to fakemachine. These are listed lower case, but
 	// they are detected and configured in both lower case and upper case.
-	var environVars = [...]string{
+	environVars := [...]string{
 		"http_proxy",
 		"https_proxy",
 		"ftp_proxy",
@@ -166,7 +170,7 @@ func SetupEnviron(m *fakemachine.Machine, options Options) {
 	}
 
 	// Puts in a format that is compatible with output of os.Environ()
-	EnvironString := []string{}
+	EnvironString := make([]string, 0, len(EnvironVars))
 	for k, v := range EnvironVars {
 		warnLocalhost(k, v)
 		EnvironString = append(EnvironString, fmt.Sprintf("%s=%s", k, v))

cpio/writerhelper.go

@@ -10,7 +10,7 @@ import (
 	"path/filepath"
 	"strings"
 
-	"github.com/surma/gocpio"
+	cpio "github.com/surma/gocpio"
 )
 
 type WriterHelper struct {
@@ -54,7 +54,7 @@ func (w *WriterHelper) ensureBaseDirectory(directory string) error {
 			continue
 		}
 
-		err := w.WriteDirectory(collector, 0755)
+		err := w.WriteDirectory(collector, 0o755)
 		if err != nil {
 			return err
 		}
@@ -184,11 +184,12 @@ func (w *WriterHelper) CopyTree(path string) error {
 		if err != nil {
 			return fmt.Errorf("error visiting %s: %w", p, err)
 		}
-		if info.Mode().IsDir() {
+		switch {
+		case info.Mode().IsDir():
 			err = w.WriteDirectory(p, info.Mode() & ^os.ModeType)
-		} else if info.Mode().IsRegular() {
+		case info.Mode().IsRegular():
 			err = w.CopyFile(p)
-		} else {
+		default:
 			err = fmt.Errorf("file type not handled for %s", p)
 		}
 

decompressors.go

@@ -30,7 +30,7 @@ func XzDecompressor(dst io.Writer, src io.Reader) error {
 		return fmt.Errorf("failed to create xz decompressor: %w", err)
 	}
 	// There is no Close() API. See: https://github.com/ulikunitz/xz/issues/45
-	//defer decompressor.Close()
+	// defer decompressor.Close()
 
 	_, err = io.Copy(dst, decompressor)
 	if err != nil {

decompressors_test.go

@@ -10,7 +10,7 @@ import (
 	"path"
 	"testing"
 
-	"github.com/go-debos/fakemachine/cpio"
+	writerhelper "github.com/go-debos/fakemachine/cpio"
 	"github.com/stretchr/testify/require"
 )