enhance linters configuration and improve code readability

.golangci.yml

@@ -3,6 +3,9 @@ version: "2"
 linters:
   enable:
     - errorlint
+    - gocritic
+    - modernize
+    - revive
     - unconvert
     - unparam
   exclusions:
@@ -11,6 +14,28 @@ linters:
       - comments
       - std-error-handling
   settings:
+    gocritic:
+      disabled-checks:
+        - appendAssign
+        - builtinShadow
+        - deferInLoop
+        - hugeParam
+        - unnamedResult
+        - whyNoLint
+      enable-all: true
+    revive:
+      enable-all-rules: false
+      enable-default-rules: true
+      max-open-files: 2048
+      rules:
+        - name: dot-imports
+          disabled: true
+        - name: package-comments
+          disabled: true
+        - name: redefines-builtin-id
+          disabled: true
+        - name: var-naming
+          disabled: true
     staticcheck:
       # Enable all options, with some exceptions.
       # For defaults, see https://golangci-lint.run/usage/linters/#staticcheck
@@ -24,3 +49,7 @@ formatters:
     - gofumpt
   exclusions:
     generated: disable
+
+issues:
+  max-issues-per-linter: 0
+  max-same-issues: 0

capability/capability_linux.go

@@ -77,11 +77,12 @@ func mkString(c Capabilities, max CapType) (ret string) {
 	ret = "{"
 	for i := CapType(1); i <= max; i <<= 1 {
 		ret += " " + i.String() + "=\""
-		if c.Empty(i) {
+		switch {
+		case c.Empty(i):
 			ret += "empty"
-		} else if c.Full(i) {
+		case c.Full(i):
 			ret += "full"
-		} else {
+		default:
 			ret += c.StringCap(i)
 		}
 		ret += "\""

capability/capability_test.go

@@ -133,7 +133,7 @@ func TestNewPid2Load(t *testing.T) {
 	// Assuming that at least bounding set is not empty.
 	bset := c.StringCap(BOUNDING)
 	t.Logf("Bounding set: %s", bset)
-	if len(bset) == 0 {
+	if bset == "" {
 		t.Fatal("loaded bounding set: want non-empty, got empty")
 	}
 }

devices/device_unix_test.go

@@ -42,7 +42,7 @@ func TestDeviceFromPathLstatFailure(t *testing.T) {
 	testError := errors.New("test error")
 
 	// Override unix.Lstat to inject error.
-	unixLstat = func(path string, stat *unix.Stat_t) error {
+	unixLstat = func(_ string, _ *unix.Stat_t) error {
 		return testError
 	}
 	defer cleanupTest()
@@ -57,7 +57,7 @@ func TestHostDevicesIoutilReadDirFailure(t *testing.T) {
 	testError := errors.New("test error")
 
 	// Override os.ReadDir to inject error.
-	osReadDir = func(dirname string) ([]fs.DirEntry, error) {
+	osReadDir = func(_ string) ([]fs.DirEntry, error) {
 		return nil, testError
 	}
 	defer cleanupTest()
@@ -73,7 +73,7 @@ func TestHostDevicesIoutilReadDirDeepFailure(t *testing.T) {
 	called := false
 
 	// Override os.ReadDir to inject error after the first call.
-	osReadDir = func(dirname string) ([]fs.DirEntry, error) {
+	osReadDir = func(_ string) ([]fs.DirEntry, error) {
 		if called {
 			return nil, testError
 		}

mount/mounter_linux_test.go

@@ -106,7 +106,7 @@ func ensureUnmount(t *testing.T, mnt string) {
 }
 
 // validateMount checks that mnt has the given options
-func validateMount(t *testing.T, mnt string, opts, optional, vfs string) {
+func validateMount(t *testing.T, mnt, opts, optional, vfs string) {
 	info, err := mountinfo.GetMounts(nil)
 	if err != nil {
 		t.Fatal(err)

mount/sharedsubtree_linux_test.go

@@ -313,9 +313,7 @@ func TestSubtreeUnbindable(t *testing.T) {
 	} else if err == nil {
 		t.Fatalf("%q should not have been bindable", sourceDir)
 	}
-	defer func() {
-		if err := Unmount(targetDir); err != nil {
-			t.Fatal(err)
-		}
-	}()
+	if err := Unmount(targetDir); err != nil {
+		t.Fatal(err)
+	}
 }

mountinfo/mounted_linux_test.go

@@ -60,7 +60,7 @@ var testMounts = []testMount{
 	{
 		desc:       "non-existent path",
 		isNotExist: true,
-		prepare: func(t *testing.T) string {
+		prepare: func(_ *testing.T) string {
 			return "/non/existent/path"
 		},
 	},
@@ -385,9 +385,7 @@ func TestMountedBy(t *testing.T) {
 						t.Errorf("%s: expected false on error", name)
 					}
 				} else if mounted != tc.isMount {
-					if tc.isBind && strings.HasSuffix(name, "mountedByStat") {
-						// mountedByStat can not detect bind mounts.
-					} else {
+					if !tc.isBind || !strings.HasSuffix(name, "mountedByStat") {
 						t.Errorf("%s: expected %v, got %v", name, tc.isMount, mounted)
 					}
 				}

reexec/reexec_test.go

@@ -212,7 +212,7 @@ func TestDispatch(t *testing.T) {
 	}{
 		{
 			name: "not-registered",
-			ctx: func(t *testing.T) context.Context {
+			ctx: func(_ *testing.T) context.Context {
 				return context.Background()
 			},
 			check: func(t *testing.T, ok bool, err error) {

signal/signal.go

@@ -41,11 +41,11 @@ func ParseSignal(rawSignal string) (syscall.Signal, error) {
 		}
 		return syscall.Signal(s), nil
 	}
-	signal, ok := SignalMap[strings.TrimPrefix(strings.ToUpper(rawSignal), "SIG")]
+	sig, ok := SignalMap[strings.TrimPrefix(strings.ToUpper(rawSignal), "SIG")]
 	if !ok {
 		return -1, fmt.Errorf("invalid signal: %s", rawSignal)
 	}
-	return signal, nil
+	return sig, nil
 }
 
 // ValidSignalForPlatform returns true if a signal is valid on the platform

user/idtools_unix.go

@@ -51,16 +51,16 @@ func mkdirAs(path string, mode os.FileMode, uid, gid int, mkAll, onlyNew bool) e
 				paths = append(paths, dirPath)
 			}
 		}
-		if err = os.MkdirAll(path, mode); err != nil {
+		if err := os.MkdirAll(path, mode); err != nil {
 			return err
 		}
-	} else if err = os.Mkdir(path, mode); err != nil {
+	} else if err := os.Mkdir(path, mode); err != nil {
 		return err
 	}
 	// even if it existed, we will chown the requested path + any subpaths that
 	// didn't exist when we called MkdirAll
 	for _, pathComponent := range paths {
-		if err = setPermissions(pathComponent, mode, uid, gid, nil); err != nil {
+		if err := setPermissions(pathComponent, mode, uid, gid, nil); err != nil {
 			return err
 		}
 	}
@@ -137,7 +137,7 @@ func lookupSubRangesFile(path string, usr User) ([]IDMap, error) {
 			ParentID: idrange.SubID,
 			Count:    idrange.Count,
 		})
-		containerID = containerID + idrange.Count
+		containerID += idrange.Count
 	}
 	return idMap, nil
 }