Use errors.As() instead of type assertions

It is more idiomatic because it also works for wrapped errors.

Signed-off-by: Jan Dubois <jan.dubois@suse.com>

Author: jandubois

cmd/limactl/main.go

@@ -47,7 +47,7 @@ func main() {
 	rootCmd := newApp()
 	if err := executeWithPluginSupport(rootCmd, os.Args[1:]); err != nil {
 		server.StopAllExternalDrivers()
-		handleExitCoder(err)
+		handleExitError(err)
 		logrus.Fatal(err)
 	}
 
@@ -200,17 +200,13 @@ func newApp() *cobra.Command {
 	return rootCmd
 }
 
-type ExitCoder interface {
-	error
-	ExitCode() int
-}
-
-func handleExitCoder(err error) {
+func handleExitError(err error) {
 	if err == nil {
 		return
 	}
 
-	if exitErr, ok := err.(ExitCoder); ok {
+	var exitErr *exec.ExitError
+	if errors.As(err, &exitErr) {
 		os.Exit(exitErr.ExitCode()) //nolint:revive // it's intentional to call os.Exit in this function
 		return
 	}
@@ -253,7 +249,7 @@ func runExternalPlugin(ctx context.Context, name string, args []string) {
 	cmd.Env = os.Environ()
 
 	err = cmd.Run()
-	handleExitCoder(err)
+	handleExitError(err)
 	if err == nil {
 		os.Exit(0) //nolint:revive // it's intentional to call os.Exit in this function
 	}

pkg/downloader/downloader.go

@@ -564,8 +564,9 @@ func decompressLocal(ctx context.Context, decompressCmd, dst, src, ext, descript
 	bar.Start()
 	err = cmd.Run()
 	if err != nil {
-		if ee, ok := err.(*exec.ExitError); ok {
-			ee.Stderr = buf.Bytes()
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			exitErr.Stderr = buf.Bytes()
 		}
 	}
 	bar.Finish()

pkg/networks/usernet/udpfileconn.go

@@ -16,7 +16,8 @@ type UDPFileConn struct {
 func (conn *UDPFileConn) Read(b []byte) (n int, err error) {
 	// Check if the connection has been closed
 	if err := conn.SetReadDeadline(time.Time{}); err != nil {
-		if opErr, ok := err.(*net.OpError); ok && opErr.Err.Error() == "use of closed network connection" {
+		var opErr *net.OpError
+		if errors.As(err, &opErr) && opErr.Err.Error() == "use of closed network connection" {
 			return 0, errors.New("UDPFileConn connection closed")
 		}
 	}