all: replace uses of ioutil with io and os (#24869)

node/config.go

@@ -19,7 +19,6 @@ package node
 import (
 	"crypto/ecdsa"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -470,7 +469,7 @@ func getKeyStoreDir(conf *Config) (string, bool, error) {
 	isEphemeral := false
 	if keydir == "" {
 		// There is no datadir.
-		keydir, err = ioutil.TempDir("", "go-ethereum-keystore")
+		keydir, err = os.MkdirTemp("", "go-ethereum-keystore")
 		isEphemeral = true
 	}
 

node/config_test.go

@@ -18,7 +18,6 @@ package node
 
 import (
 	"bytes"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -54,7 +53,7 @@ func TestDatadirCreation(t *testing.T) {
 		t.Fatalf("freshly created datadir not accessible: %v", err)
 	}
 	// Verify that an impossible datadir fails creation
-	file, err := ioutil.TempFile("", "")
+	file, err := os.CreateTemp("", "")
 	if err != nil {
 		t.Fatalf("failed to create temporary file: %v", err)
 	}
@@ -132,7 +131,7 @@ func TestNodeKeyPersistency(t *testing.T) {
 	if _, err = crypto.LoadECDSA(keyfile); err != nil {
 		t.Fatalf("failed to load freshly persisted node key: %v", err)
 	}
-	blob1, err := ioutil.ReadFile(keyfile)
+	blob1, err := os.ReadFile(keyfile)
 	if err != nil {
 		t.Fatalf("failed to read freshly persisted node key: %v", err)
 	}
@@ -140,7 +139,7 @@ func TestNodeKeyPersistency(t *testing.T) {
 	// Configure a new node and ensure the previously persisted key is loaded
 	config = &Config{Name: "unit-test", DataDir: dir}
 	config.NodeKey()
-	blob2, err := ioutil.ReadFile(filepath.Join(keyfile))
+	blob2, err := os.ReadFile(filepath.Join(keyfile))
 	if err != nil {
 		t.Fatalf("failed to read previously persisted node key: %v", err)
 	}

node/rpcstack.go

@@ -21,7 +21,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"sort"
@@ -444,7 +443,7 @@ func (h *virtualHostHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 var gzPool = sync.Pool{
 	New: func() interface{} {
-		w := gzip.NewWriter(ioutil.Discard)
+		w := gzip.NewWriter(io.Discard)
 		return w
 	},
 }