*: use Go 1.13+ errors.Is instead of os.IsNotExist

Signed-off-by: Matt Layher <[email protected]>

Author: mdlayher

client.go

@@ -1,6 +1,7 @@
 package wgctrl
 
 import (
+	"errors"
 	"os"
 
 	"golang.zx2c4.com/wireguard/wgctrl/internal/wginternal"
@@ -58,14 +59,14 @@ func (c *Client) Devices() ([]*wgtypes.Device, error) {
 // Device retrieves a WireGuard device by its interface name.
 //
 // If the device specified by name does not exist or is not a WireGuard device,
-// an error is returned which can be checked using os.IsNotExist.
+// an error is returned which can be checked using `errors.Is(err, os.ErrNotExist)`.
 func (c *Client) Device(name string) (*wgtypes.Device, error) {
 	for _, wgc := range c.cs {
 		d, err := wgc.Device(name)
 		switch {
 		case err == nil:
 			return d, nil
-		case os.IsNotExist(err):
+		case errors.Is(err, os.ErrNotExist):
 			continue
 		default:
 			return nil, err
@@ -82,14 +83,14 @@ func (c *Client) Device(name string) (*wgtypes.Device, error) {
 // configuring a device.
 //
 // If the device specified by name does not exist or is not a WireGuard device,
-// an error is returned which can be checked using os.IsNotExist.
+// an error is returned which can be checked using `errors.Is(err, os.ErrNotExist)`.
 func (c *Client) ConfigureDevice(name string, cfg wgtypes.Config) error {
 	for _, wgc := range c.cs {
 		err := wgc.ConfigureDevice(name, cfg)
 		switch {
 		case err == nil:
 			return nil
-		case os.IsNotExist(err):
+		case errors.Is(err, os.ErrNotExist):
 			continue
 		default:
 			return err

client_integration_test.go

@@ -1,6 +1,7 @@
 package wgctrl_test
 
 import (
+	"errors"
 	"fmt"
 	"net"
 	"os"
@@ -91,7 +92,7 @@ func TestIntegrationClientIsNotExist(t *testing.T) {
 	c, done := integrationClient(t)
 	defer done()
 
-	if _, err := c.Device("wgnotexist0"); !os.IsNotExist(err) {
+	if _, err := c.Device("wgnotexist0"); !errors.Is(err, os.ErrNotExist) {
 		t.Fatalf("expected is not exist error, but got: %v", err)
 	}
 }
@@ -111,7 +112,7 @@ func integrationClient(t *testing.T) (*wgctrl.Client, func()) {
 
 	c, err := wgctrl.New()
 	if err != nil {
-		if os.IsNotExist(err) {
+		if errors.Is(err, os.ErrNotExist) {
 			t.Skip("skipping, wgctrl is not available on this system")
 		}
 

internal/wglinux/client_linux.go

@@ -3,6 +3,7 @@
 package wglinux
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"syscall"
@@ -43,10 +44,7 @@ func initClient(c *genetlink.Conn) (*Client, bool, error) {
 	if err != nil {
 		_ = c.Close()
 
-		//lint:ignore SA1019 maintain compatibility with old versions of Go
-		// by using netlink.IsNotExist for now. We can switch to errors.Is at
-		// a later time.
-		if netlink.IsNotExist(err) {
+		if errors.Is(err, os.ErrNotExist) {
 			// The generic netlink interface is not available.
 			return nil, false, nil
 		}
@@ -157,8 +155,8 @@ func (c *Client) execute(command uint8, flags netlink.HeaderFlags, attrb []byte)
 		return msgs, nil
 	}
 
-	// We don't want to expose netlink errors directly to callers, so unpack
-	// the error for use with os.IsNotExist and similar.
+	// We don't want to expose netlink errors directly to callers so unpack to
+	// something more generic.
 	oerr, ok := err.(*netlink.OpError)
 	if !ok {
 		// Expect all errors to conform to netlink.OpError.
@@ -167,7 +165,7 @@ func (c *Client) execute(command uint8, flags netlink.HeaderFlags, attrb []byte)
 
 	switch oerr.Err {
 	// Convert "no such device" and "not a wireguard device" to an error
-	// compatible with os.IsNotExist for easy checking.
+	// compatible with os.ErrNotExist for easy checking.
 	case unix.ENODEV, unix.ENOTSUP:
 		return nil, os.ErrNotExist
 	default:

internal/wglinux/client_linux_test.go

@@ -3,6 +3,7 @@
 package wglinux
 
 import (
+	"errors"
 	"fmt"
 	"net"
 	"os"
@@ -119,7 +120,7 @@ func TestLinuxClientIsNotExist(t *testing.T) {
 			})
 			defer c.Close()
 
-			if err := tt.fn(c); !os.IsNotExist(err) {
+			if err := tt.fn(c); !errors.Is(err, os.ErrNotExist) {
 				t.Fatalf("expected is not exist, but got: %v", err)
 			}
 		})

internal/wgopenbsd/client_openbsd_test.go

@@ -283,7 +283,7 @@ func TestClientDeviceNotExist(t *testing.T) {
 				},
 			}
 
-			if _, err := c.Device("wgnotexist0"); !os.IsNotExist(err) {
+			if _, err := c.Device("wgnotexist0"); !errors.Is(err, os.ErrNotExist) {
 				t.Fatalf("expected is not exist, but got: %v", err)
 			}
 		})

internal/wguser/client_test.go

@@ -1,6 +1,7 @@
 package wguser
 
 import (
+	"errors"
 	"os"
 	"strings"
 	"sync"
@@ -44,7 +45,7 @@ func TestClientDevice(t *testing.T) {
 
 			dev, err := c.Device(tt.device)
 			if err != nil {
-				if !tt.exists && os.IsNotExist(err) {
+				if !tt.exists && errors.Is(err, os.ErrNotExist) {
 					return
 				}
 

internal/wguser/configure_test.go

@@ -1,6 +1,7 @@
 package wguser
 
 import (
+	"errors"
 	"net"
 	"os"
 	"testing"
@@ -68,10 +69,10 @@ func TestClientConfigureDeviceError(t *testing.T) {
 				t.Fatal("expected an error, but none occurred")
 			}
 
-			if !tt.notExist && os.IsNotExist(err) {
+			if !tt.notExist && errors.Is(err, os.ErrNotExist) {
 				t.Fatalf("expected other error, but got not exist: %v", err)
 			}
-			if tt.notExist && !os.IsNotExist(err) {
+			if tt.notExist && !errors.Is(err, os.ErrNotExist) {
 				t.Fatalf("expected not exist error, but got: %v", err)
 			}
 		})

internal/wguser/conn_unix.go

@@ -3,6 +3,7 @@
 package wguser
 
 import (
+	"errors"
 	"io/ioutil"
 	"net"
 	"os"
@@ -29,7 +30,7 @@ func findUNIXSockets(dirs []string) ([]string, error) {
 	for _, d := range dirs {
 		files, err := ioutil.ReadDir(d)
 		if err != nil {
-			if os.IsNotExist(err) {
+			if errors.Is(err, os.ErrNotExist) {
 				continue
 			}
 

internal/wguser/conn_windows_test.go

@@ -3,6 +3,7 @@
 package wguser
 
 import (
+	"errors"
 	"fmt"
 	"net"
 	"os"
@@ -18,7 +19,7 @@ var isWINE = func() bool {
 	// Reference: https://forum.winehq.org/viewtopic.php?t=4988.
 	k, err := registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\Wine`, registry.QUERY_VALUE)
 	if err != nil {
-		if os.IsNotExist(err) {
+		if errors.Is(err, os.ErrNotExist) {
 			// No key; the tests don't appear to be running in WINE.
 			return false
 		}