From 17e1598d4e797b53c78248dcf6f2968a83315106 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Sun, 22 Oct 2023 04:47:03 +0900
Subject: [PATCH 01/14] notJoon:remove-deprecated-io/ioutil

---
 gnovm/pkg/gnolang/nodes.go      | 3 +--
 gnovm/pkg/gnolang/precompile.go | 3 +--
 gnovm/pkg/gnomod/gnomod.go      | 5 ++---
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/gnovm/pkg/gnolang/nodes.go b/gnovm/pkg/gnolang/nodes.go
index 46308fb3a02..2a9e0b51a97 100644
--- a/gnovm/pkg/gnolang/nodes.go
+++ b/gnovm/pkg/gnolang/nodes.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"go/parser"
 	"go/token"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -1095,7 +1094,7 @@ func PackageNameFromFileBody(name, body string) Name {
 
 // NOTE: panics if package name is invalid.
 func ReadMemPackage(dir string, pkgPath string) *std.MemPackage {
-	files, err := ioutil.ReadDir(dir)
+	files, err := os.ReadDir(dir)
 	if err != nil {
 		panic(err)
 	}
diff --git a/gnovm/pkg/gnolang/precompile.go b/gnovm/pkg/gnolang/precompile.go
index f7a10d5589a..c3116f25800 100644
--- a/gnovm/pkg/gnolang/precompile.go
+++ b/gnovm/pkg/gnolang/precompile.go
@@ -7,7 +7,6 @@ import (
 	"go/format"
 	"go/parser"
 	"go/token"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -112,7 +111,7 @@ func GetPrecompileFilenameAndTags(gnoFilePath string) (targetFilename, tags stri
 func PrecompileAndCheckMempkg(mempkg *std.MemPackage) error {
 	gofmt := "gofmt"
 
-	tmpDir, err := ioutil.TempDir("", mempkg.Name)
+	tmpDir, err := os.MkdirTemp("", mempkg.Name)
 	if err != nil {
 		return err
 	}
diff --git a/gnovm/pkg/gnomod/gnomod.go b/gnovm/pkg/gnomod/gnomod.go
index 7bb51d6558a..3c224bafb87 100644
--- a/gnovm/pkg/gnomod/gnomod.go
+++ b/gnovm/pkg/gnomod/gnomod.go
@@ -3,7 +3,6 @@ package gnomod
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -172,9 +171,9 @@ func CreateGnoModFile(rootDir, modPath string) error {
 	if modPath == "" {
 		// Check .gno files for package name
 		// and use it as modPath
-		files, err := ioutil.ReadDir(rootDir)
+		files, err := os.ReadDir(rootDir)
 		if err != nil {
-			fmt.Errorf("read dir %q: %w", rootDir, err)
+			return fmt.Errorf("read dir %q: %w", rootDir, err)
 		}
 
 		var pkgName gnolang.Name

From 92646bb1d3f1ac93dabc42224500fd2027396307 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Tue, 24 Oct 2023 15:54:24 +0900
Subject: [PATCH 02/14] replace ioutil package in tm2

---
 tm2/pkg/amino/genproto/genproto.go            |  5 +---
 tm2/pkg/autofile/autofile_test.go             |  7 +++---
 tm2/pkg/bft/config/toml.go                    |  3 +--
 tm2/pkg/bft/consensus/common_test.go          |  7 +++---
 tm2/pkg/bft/consensus/replay_test.go          |  3 +--
 tm2/pkg/bft/privval/file_test.go              | 25 +++++++++----------
 tm2/pkg/bft/privval/socket_listeners_test.go  |  3 +--
 tm2/pkg/bft/rpc/client/main_test.go           |  3 +--
 tm2/pkg/bft/rpc/lib/client/http_client.go     |  8 +++---
 tm2/pkg/bft/rpc/lib/server/handlers.go        |  4 +--
 tm2/pkg/bft/rpc/lib/server/handlers_test.go   | 10 ++++----
 .../bft/rpc/lib/server/http_server_test.go    |  5 ++--
 tm2/pkg/bft/types/genesis_test.go             |  3 +--
 tm2/pkg/bft/types/part_set_test.go            |  4 +--
 tm2/pkg/db/fsdb.go                            |  4 +--
 tm2/pkg/iavl/tree_dotgraph_test.go            |  4 +--
 tm2/pkg/log/tm_logger_test.go                 |  6 ++---
 tm2/pkg/os/tempfile_test.go                   |  3 +--
 tm2/pkg/p2p/upnp/upnp.go                      |  6 ++---
 19 files changed, 50 insertions(+), 63 deletions(-)

diff --git a/tm2/pkg/amino/genproto/genproto.go b/tm2/pkg/amino/genproto/genproto.go
index 8af73b2690a..4f7154e058c 100644
--- a/tm2/pkg/amino/genproto/genproto.go
+++ b/tm2/pkg/amino/genproto/genproto.go
@@ -6,7 +6,6 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -120,7 +119,6 @@ func (p3c *P3Context) GetP3ImportPath(p3type P3Type, implicit bool) string {
 func (p3c *P3Context) GenerateProto3MessagePartial(p3doc *P3Doc, rt reflect.Type) (p3msg P3Message) {
 	if p3doc.PackageName == "" {
 		panic(fmt.Sprintf("cannot generate message partials in the root package \"\"."))
-		return
 	}
 	if rt.Kind() == reflect.Ptr {
 		panic("pointers not yet supported. if you meant pointer-preferred (for decoding), pass in rt.Elem()")
@@ -220,7 +218,6 @@ func (p3c *P3Context) GenerateProto3MessagePartial(p3doc *P3Doc, rt reflect.Type
 func (p3c *P3Context) GenerateProto3ListPartial(p3doc *P3Doc, nl NList) (p3msg P3Message) {
 	if p3doc.PackageName == "" {
 		panic(fmt.Sprintf("cannot generate message partials in the root package \"\"."))
-		return
 	}
 
 	ep3 := nl.ElemP3Type()
@@ -496,7 +493,7 @@ func RunProtoc(pkg *amino.Package, protosDir string) {
 		}
 	}
 	// First generate output to a temp dir.
-	tempDir, err := ioutil.TempDir("", "amino-genproto")
+	tempDir, err := os.MkdirTemp("", "amino-genproto")
 	if err != nil {
 		return
 	}
diff --git a/tm2/pkg/autofile/autofile_test.go b/tm2/pkg/autofile/autofile_test.go
index d50bdca3ce0..d631e0ed265 100644
--- a/tm2/pkg/autofile/autofile_test.go
+++ b/tm2/pkg/autofile/autofile_test.go
@@ -1,7 +1,6 @@
 package autofile
 
 import (
-	"io/ioutil"
 	"os"
 	"syscall"
 	"testing"
@@ -14,7 +13,7 @@ import (
 
 func TestSIGHUP(t *testing.T) {
 	// First, create an AutoFile writing to a tempfile dir
-	file, err := ioutil.TempFile("", "sighup_test")
+	file, err := os.CreateTemp("", "sighup_test")
 	require.NoError(t, err)
 	err = file.Close()
 	require.NoError(t, err)
@@ -60,7 +59,7 @@ func TestSIGHUP(t *testing.T) {
 // // Manually modify file permissions, close, and reopen using autofile:
 // // We expect the file permissions to be changed back to the intended perms.
 // func TestOpenAutoFilePerms(t *testing.T) {
-// 	file, err := ioutil.TempFile("", "permission_test")
+// 	file, err := os.CreateTemp("", "permission_test")
 // 	require.NoError(t, err)
 // 	err = file.Close()
 // 	require.NoError(t, err)
@@ -86,7 +85,7 @@ func TestSIGHUP(t *testing.T) {
 
 func TestAutoFileSize(t *testing.T) {
 	// First, create an AutoFile writing to a tempfile dir
-	f, err := ioutil.TempFile("", "sighup_test")
+	f, err := os.CreateTemp("", "sighup_test")
 	require.NoError(t, err)
 	err = f.Close()
 	require.NoError(t, err)
diff --git a/tm2/pkg/bft/config/toml.go b/tm2/pkg/bft/config/toml.go
index fdaa1295342..1599bc78968 100644
--- a/tm2/pkg/bft/config/toml.go
+++ b/tm2/pkg/bft/config/toml.go
@@ -3,7 +3,6 @@ package config
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"text/template"
@@ -308,7 +307,7 @@ func ResetTestRoot(testName string) *Config {
 
 func ResetTestRootWithChainID(testName string, chainID string) *Config {
 	// create a unique, concurrency-safe test directory under os.TempDir()
-	rootDir, err := ioutil.TempDir("", fmt.Sprintf("%s-%s_", chainID, testName))
+	rootDir, err := os.MkdirTemp("", fmt.Sprintf("%s-%s_", chainID, testName))
 	if err != nil {
 		panic(err)
 	}
diff --git a/tm2/pkg/bft/consensus/common_test.go b/tm2/pkg/bft/consensus/common_test.go
index 7424305c00a..19c96756624 100644
--- a/tm2/pkg/bft/consensus/common_test.go
+++ b/tm2/pkg/bft/consensus/common_test.go
@@ -3,7 +3,6 @@ package consensus
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
@@ -662,11 +661,11 @@ func randConsensusNetWithPeers(nValidators, nPeers int, testName string, tickerF
 		if i < nValidators {
 			privVal = privVals[i]
 		} else {
-			tempKeyFile, err := ioutil.TempFile("", "priv_validator_key_")
+			tempKeyFile, err := os.CreateTemp("", "priv_validator_key_")
 			if err != nil {
 				panic(err)
 			}
-			tempStateFile, err := ioutil.TempFile("", "priv_validator_state_")
+			tempStateFile, err := os.CreateTemp("", "priv_validator_state_")
 			if err != nil {
 				panic(err)
 			}
@@ -795,7 +794,7 @@ func newCounter() abci.Application {
 }
 
 func newPersistentKVStore() abci.Application {
-	dir, err := ioutil.TempDir("", "persistent-kvstore")
+	dir, err := os.MkdirTemp("", "persistent-kvstore")
 	if err != nil {
 		panic(err)
 	}
diff --git a/tm2/pkg/bft/consensus/replay_test.go b/tm2/pkg/bft/consensus/replay_test.go
index 3174207ef8d..556689ec3f4 100644
--- a/tm2/pkg/bft/consensus/replay_test.go
+++ b/tm2/pkg/bft/consensus/replay_test.go
@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -604,7 +603,7 @@ func TestMockProxyApp(t *testing.T) {
 }
 
 func tempWALWithData(data []byte) string {
-	walFile, err := ioutil.TempFile("", "wal")
+	walFile, err := os.CreateTemp("", "wal")
 	if err != nil {
 		panic(fmt.Sprintf("failed to create temp WAL file: %v", err))
 	}
diff --git a/tm2/pkg/bft/privval/file_test.go b/tm2/pkg/bft/privval/file_test.go
index 306db4177e5..36979e19ea3 100644
--- a/tm2/pkg/bft/privval/file_test.go
+++ b/tm2/pkg/bft/privval/file_test.go
@@ -3,7 +3,6 @@ package privval
 import (
 	"encoding/base64"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"testing"
 	"time"
@@ -20,9 +19,9 @@ import (
 func TestGenLoadValidator(t *testing.T) {
 	assert := assert.New(t)
 
-	tempKeyFile, err := ioutil.TempFile("", "priv_validator_key_")
+	tempKeyFile, err := os.CreateTemp("", "priv_validator_key_")
 	require.Nil(t, err)
-	tempStateFile, err := ioutil.TempFile("", "priv_validator_state_")
+	tempStateFile, err := os.CreateTemp("", "priv_validator_state_")
 	require.Nil(t, err)
 
 	privVal := GenFilePV(tempKeyFile.Name(), tempStateFile.Name())
@@ -38,9 +37,9 @@ func TestGenLoadValidator(t *testing.T) {
 }
 
 func TestResetValidator(t *testing.T) {
-	tempKeyFile, err := ioutil.TempFile("", "priv_validator_key_")
+	tempKeyFile, err := os.CreateTemp("", "priv_validator_key_")
 	require.Nil(t, err)
-	tempStateFile, err := ioutil.TempFile("", "priv_validator_state_")
+	tempStateFile, err := os.CreateTemp("", "priv_validator_state_")
 	require.Nil(t, err)
 
 	privVal := GenFilePV(tempKeyFile.Name(), tempStateFile.Name())
@@ -68,9 +67,9 @@ func TestResetValidator(t *testing.T) {
 func TestLoadOrGenValidator(t *testing.T) {
 	assert := assert.New(t)
 
-	tempKeyFile, err := ioutil.TempFile("", "priv_validator_key_")
+	tempKeyFile, err := os.CreateTemp("", "priv_validator_key_")
 	require.Nil(t, err)
-	tempStateFile, err := ioutil.TempFile("", "priv_validator_state_")
+	tempStateFile, err := os.CreateTemp("", "priv_validator_state_")
 	require.Nil(t, err)
 
 	tempKeyFilePath := tempKeyFile.Name()
@@ -160,9 +159,9 @@ func TestUnmarshalValidatorKey(t *testing.T) {
 func TestSignVote(t *testing.T) {
 	assert := assert.New(t)
 
-	tempKeyFile, err := ioutil.TempFile("", "priv_validator_key_")
+	tempKeyFile, err := os.CreateTemp("", "priv_validator_key_")
 	require.Nil(t, err)
-	tempStateFile, err := ioutil.TempFile("", "priv_validator_state_")
+	tempStateFile, err := os.CreateTemp("", "priv_validator_state_")
 	require.Nil(t, err)
 
 	privVal := GenFilePV(tempKeyFile.Name(), tempStateFile.Name())
@@ -206,9 +205,9 @@ func TestSignVote(t *testing.T) {
 func TestSignProposal(t *testing.T) {
 	assert := assert.New(t)
 
-	tempKeyFile, err := ioutil.TempFile("", "priv_validator_key_")
+	tempKeyFile, err := os.CreateTemp("", "priv_validator_key_")
 	require.Nil(t, err)
-	tempStateFile, err := ioutil.TempFile("", "priv_validator_state_")
+	tempStateFile, err := os.CreateTemp("", "priv_validator_state_")
 	require.Nil(t, err)
 
 	privVal := GenFilePV(tempKeyFile.Name(), tempStateFile.Name())
@@ -248,9 +247,9 @@ func TestSignProposal(t *testing.T) {
 }
 
 func TestDifferByTimestamp(t *testing.T) {
-	tempKeyFile, err := ioutil.TempFile("", "priv_validator_key_")
+	tempKeyFile, err := os.CreateTemp("", "priv_validator_key_")
 	require.Nil(t, err)
-	tempStateFile, err := ioutil.TempFile("", "priv_validator_state_")
+	tempStateFile, err := os.CreateTemp("", "priv_validator_state_")
 	require.Nil(t, err)
 
 	privVal := GenFilePV(tempKeyFile.Name(), tempStateFile.Name())
diff --git a/tm2/pkg/bft/privval/socket_listeners_test.go b/tm2/pkg/bft/privval/socket_listeners_test.go
index a3630903197..6ca7863d1fd 100644
--- a/tm2/pkg/bft/privval/socket_listeners_test.go
+++ b/tm2/pkg/bft/privval/socket_listeners_test.go
@@ -1,7 +1,6 @@
 package privval
 
 import (
-	"io/ioutil"
 	"net"
 	"os"
 	"testing"
@@ -29,7 +28,7 @@ type listenerTestCase struct {
 // testUnixAddr will attempt to obtain a platform-independent temporary file
 // name for a Unix socket
 func testUnixAddr() (string, error) {
-	f, err := ioutil.TempFile("", "tendermint-privval-test-*")
+	f, err := os.CreateTemp("", "tendermint-privval-test-*")
 	if err != nil {
 		return "", err
 	}
diff --git a/tm2/pkg/bft/rpc/client/main_test.go b/tm2/pkg/bft/rpc/client/main_test.go
index 58dd9538412..759104a3029 100644
--- a/tm2/pkg/bft/rpc/client/main_test.go
+++ b/tm2/pkg/bft/rpc/client/main_test.go
@@ -1,7 +1,6 @@
 package client_test
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -14,7 +13,7 @@ var node *nm.Node
 
 func TestMain(m *testing.M) {
 	// start a tendermint node (and kvstore) in the background to test against
-	dir, err := ioutil.TempDir("/tmp", "rpc-client-test")
+	dir, err := os.MkdirTemp("/tmp", "rpc-client-test")
 	if err != nil {
 		panic(err)
 	}
diff --git a/tm2/pkg/bft/rpc/lib/client/http_client.go b/tm2/pkg/bft/rpc/lib/client/http_client.go
index 5a9da9ec052..c02d029f27a 100644
--- a/tm2/pkg/bft/rpc/lib/client/http_client.go
+++ b/tm2/pkg/bft/rpc/lib/client/http_client.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"net/url"
@@ -201,7 +201,7 @@ func (c *JSONRPCClient) Call(method string, params map[string]interface{}, resul
 		return nil, errors.New("server at '%s' returned %s", c.address, httpResponse.Status)
 	}
 
-	responseBytes, err := ioutil.ReadAll(httpResponse.Body)
+	responseBytes, err := io.ReadAll(httpResponse.Body)
 	if err != nil {
 		return nil, err
 	}
@@ -238,7 +238,7 @@ func (c *JSONRPCClient) sendBatch(requests []*jsonRPCBufferedRequest) ([]interfa
 		return nil, errors.New("server at '%s' returned %s", c.address, httpResponse.Status)
 	}
 
-	responseBytes, err := ioutil.ReadAll(httpResponse.Body)
+	responseBytes, err := io.ReadAll(httpResponse.Body)
 	if err != nil {
 		return nil, err
 	}
@@ -332,7 +332,7 @@ func (c *URIClient) Call(method string, params map[string]interface{}, result in
 		return nil, errors.New("server at '%s' returned %s", c.address, resp.Status)
 	}
 
-	responseBytes, err := ioutil.ReadAll(resp.Body)
+	responseBytes, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, err
 	}
diff --git a/tm2/pkg/bft/rpc/lib/server/handlers.go b/tm2/pkg/bft/rpc/lib/server/handlers.go
index aa3fadd4d18..40543e5f465 100644
--- a/tm2/pkg/bft/rpc/lib/server/handlers.go
+++ b/tm2/pkg/bft/rpc/lib/server/handlers.go
@@ -6,7 +6,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"reflect"
 	"runtime/debug"
@@ -101,7 +101,7 @@ func funcReturnTypes(f interface{}) []reflect.Type {
 // jsonrpc calls grab the given method's function info and runs reflect.Call
 func makeJSONRPCHandler(funcMap map[string]*RPCFunc, logger log.Logger) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		b, err := ioutil.ReadAll(r.Body)
+		b, err := io.ReadAll(r.Body)
 		if err != nil {
 			WriteRPCResponseHTTP(w, types.RPCInvalidRequestError(types.JSONRPCStringID(""), errors.Wrap(err, "error reading request body")))
 			return
diff --git a/tm2/pkg/bft/rpc/lib/server/handlers_test.go b/tm2/pkg/bft/rpc/lib/server/handlers_test.go
index 8bf2cc0f7f1..b7a9445a82d 100644
--- a/tm2/pkg/bft/rpc/lib/server/handlers_test.go
+++ b/tm2/pkg/bft/rpc/lib/server/handlers_test.go
@@ -3,7 +3,7 @@ package rpcserver_test
 import (
 	"bytes"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -70,7 +70,7 @@ func TestRPCParams(t *testing.T) {
 		res := rec.Result()
 		// Always expecting back a JSONRPCResponse
 		assert.True(t, statusOK(res.StatusCode), "#%d: should always return 2XX", i)
-		blob, err := ioutil.ReadAll(res.Body)
+		blob, err := io.ReadAll(res.Body)
 		if err != nil {
 			t.Errorf("#%d: err reading body: %v", i, err)
 			continue
@@ -118,7 +118,7 @@ func TestJSONRPCID(t *testing.T) {
 		res := rec.Result()
 		// Always expecting back a JSONRPCResponse
 		assert.True(t, statusOK(res.StatusCode), "#%d: should always return 2XX", i)
-		blob, err := ioutil.ReadAll(res.Body)
+		blob, err := io.ReadAll(res.Body)
 		if err != nil {
 			t.Errorf("#%d: err reading body: %v", i, err)
 			continue
@@ -147,7 +147,7 @@ func TestRPCNotification(t *testing.T) {
 
 	// Always expecting back a JSONRPCResponse
 	require.True(t, statusOK(res.StatusCode), "should always return 2XX")
-	blob, err := ioutil.ReadAll(res.Body)
+	blob, err := io.ReadAll(res.Body)
 	require.Nil(t, err, "reading from the body should not give back an error")
 	require.Equal(t, len(blob), 0, "a notification SHOULD NOT be responded to by the server")
 }
@@ -182,7 +182,7 @@ func TestRPCNotificationInBatch(t *testing.T) {
 		res := rec.Result()
 		// Always expecting back a JSONRPCResponse
 		assert.True(t, statusOK(res.StatusCode), "#%d: should always return 2XX", i)
-		blob, err := ioutil.ReadAll(res.Body)
+		blob, err := io.ReadAll(res.Body)
 		if err != nil {
 			t.Errorf("#%d: err reading body: %v", i, err)
 			continue
diff --git a/tm2/pkg/bft/rpc/lib/server/http_server_test.go b/tm2/pkg/bft/rpc/lib/server/http_server_test.go
index 6753a339981..aaf817e6d85 100644
--- a/tm2/pkg/bft/rpc/lib/server/http_server_test.go
+++ b/tm2/pkg/bft/rpc/lib/server/http_server_test.go
@@ -5,7 +5,6 @@ import (
 	"crypto/tls"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -58,7 +57,7 @@ func TestMaxOpenConnections(t *testing.T) {
 				return
 			}
 			defer r.Body.Close()
-			io.Copy(ioutil.Discard, r.Body)
+			io.Copy(io.Discard, r.Body)
 		}()
 	}
 	wg.Wait()
@@ -91,7 +90,7 @@ func TestStartHTTPAndTLSServer(t *testing.T) {
 	defer res.Body.Close()
 	assert.Equal(t, http.StatusOK, res.StatusCode)
 
-	body, err := ioutil.ReadAll(res.Body)
+	body, err := io.ReadAll(res.Body)
 	require.NoError(t, err)
 	assert.Equal(t, []byte("some body"), body)
 }
diff --git a/tm2/pkg/bft/types/genesis_test.go b/tm2/pkg/bft/types/genesis_test.go
index c8886f9bf0a..5d4c7630857 100644
--- a/tm2/pkg/bft/types/genesis_test.go
+++ b/tm2/pkg/bft/types/genesis_test.go
@@ -1,7 +1,6 @@
 package types
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -87,7 +86,7 @@ func TestGenesisGood(t *testing.T) {
 }
 
 func TestGenesisSaveAs(t *testing.T) {
-	tmpfile, err := ioutil.TempFile("", "genesis")
+	tmpfile, err := os.CreateTemp("", "genesis")
 	require.NoError(t, err)
 	defer os.Remove(tmpfile.Name())
 
diff --git a/tm2/pkg/bft/types/part_set_test.go b/tm2/pkg/bft/types/part_set_test.go
index 2e05daed849..c4e30c89372 100644
--- a/tm2/pkg/bft/types/part_set_test.go
+++ b/tm2/pkg/bft/types/part_set_test.go
@@ -1,7 +1,7 @@
 package types
 
 import (
-	"io/ioutil"
+	"io"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -54,7 +54,7 @@ func TestBasicPartSet(t *testing.T) {
 
 	// Reconstruct data, assert that they are equal.
 	data2Reader := partSet2.GetReader()
-	data2, err := ioutil.ReadAll(data2Reader)
+	data2, err := io.ReadAll(data2Reader)
 	require.NoError(t, err)
 
 	assert.Equal(t, data, data2)
diff --git a/tm2/pkg/db/fsdb.go b/tm2/pkg/db/fsdb.go
index aa8cea83889..e11cd6d4ce5 100644
--- a/tm2/pkg/db/fsdb.go
+++ b/tm2/pkg/db/fsdb.go
@@ -2,7 +2,7 @@ package db
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/url"
 	"os"
 	"path/filepath"
@@ -189,7 +189,7 @@ func read(path string) ([]byte, error) {
 	}
 	defer f.Close()
 
-	d, err := ioutil.ReadAll(f)
+	d, err := io.ReadAll(f)
 	if err != nil {
 		return nil, err
 	}
diff --git a/tm2/pkg/iavl/tree_dotgraph_test.go b/tm2/pkg/iavl/tree_dotgraph_test.go
index 29be03ca241..f3c2786cda3 100644
--- a/tm2/pkg/iavl/tree_dotgraph_test.go
+++ b/tm2/pkg/iavl/tree_dotgraph_test.go
@@ -1,7 +1,7 @@
 package iavl
 
 import (
-	"io/ioutil"
+	"io"
 	"testing"
 
 	db "github.com/gnolang/gno/tm2/pkg/db"
@@ -15,5 +15,5 @@ func TestWriteDOTGraph(t *testing.T) {
 		key := []byte{ikey}
 		tree.Set(key, key)
 	}
-	WriteDOTGraph(ioutil.Discard, tree.ImmutableTree, []PathToLeaf{})
+	WriteDOTGraph(io.Discard, tree.ImmutableTree, []PathToLeaf{})
 }
diff --git a/tm2/pkg/log/tm_logger_test.go b/tm2/pkg/log/tm_logger_test.go
index a6d56bb8feb..81614c5ea21 100644
--- a/tm2/pkg/log/tm_logger_test.go
+++ b/tm2/pkg/log/tm_logger_test.go
@@ -2,7 +2,7 @@ package log_test
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"strings"
 	"testing"
 
@@ -21,11 +21,11 @@ func TestLoggerLogsItsErrors(t *testing.T) {
 }
 
 func BenchmarkTMLoggerSimple(b *testing.B) {
-	benchmarkRunner(b, log.NewTMLogger(ioutil.Discard), baseInfoMessage)
+	benchmarkRunner(b, log.NewTMLogger(io.Discard), baseInfoMessage)
 }
 
 func BenchmarkTMLoggerContextual(b *testing.B) {
-	benchmarkRunner(b, log.NewTMLogger(ioutil.Discard), withInfoMessage)
+	benchmarkRunner(b, log.NewTMLogger(io.Discard), withInfoMessage)
 }
 
 func benchmarkRunner(b *testing.B, logger log.Logger, f func(log.Logger)) {
diff --git a/tm2/pkg/os/tempfile_test.go b/tm2/pkg/os/tempfile_test.go
index 12d6abb27cb..ec294d58e30 100644
--- a/tm2/pkg/os/tempfile_test.go
+++ b/tm2/pkg/os/tempfile_test.go
@@ -5,7 +5,6 @@ package os
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -21,7 +20,7 @@ func TestWriteFileAtomic(t *testing.T) {
 		perm os.FileMode = 0o600
 	)
 
-	f, err := ioutil.TempFile("/tmp", "write-atomic-test-")
+	f, err := os.CreateTemp("/tmp", "write-atomic-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/tm2/pkg/p2p/upnp/upnp.go b/tm2/pkg/p2p/upnp/upnp.go
index 40f2067e232..cd47ac35553 100644
--- a/tm2/pkg/p2p/upnp/upnp.go
+++ b/tm2/pkg/p2p/upnp/upnp.go
@@ -10,7 +10,7 @@ import (
 	"encoding/xml"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"strconv"
@@ -306,7 +306,7 @@ func (n *upnpNAT) getExternalIPAddress() (info statusInfo, err error) {
 		return
 	}
 	var envelope Envelope
-	data, err := ioutil.ReadAll(response.Body)
+	data, err := io.ReadAll(response.Body)
 	if err != nil {
 		return
 	}
@@ -363,7 +363,7 @@ func (n *upnpNAT) AddPortMapping(protocol string, externalPort, internalPort int
 	// TODO: check response to see if the port was forwarded
 	// log.Println(message, response)
 	// JAE:
-	// body, err := ioutil.ReadAll(response.Body)
+	// body, err := io.ReadAll(response.Body)
 	// fmt.Println(string(body), err)
 	mappedExternalPort = externalPort
 	_ = response

From dbb191ead81509d8822f72ad6057c0429be71918 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Tue, 24 Oct 2023 16:24:15 +0900
Subject: [PATCH 03/14] mv codes from ioutil to io

---
 gnovm/stdlibs/io/io.gno            | 17 ++++++
 gnovm/stdlibs/io/io_test.gno       | 67 +++++++++++++++---------
 gnovm/stdlibs/io/ioutil/ioutil.gno | 83 ------------------------------
 3 files changed, 61 insertions(+), 106 deletions(-)
 delete mode 100644 gnovm/stdlibs/io/ioutil/ioutil.gno

diff --git a/gnovm/stdlibs/io/io.gno b/gnovm/stdlibs/io/io.gno
index 54caf32cb95..186f5ca9b24 100644
--- a/gnovm/stdlibs/io/io.gno
+++ b/gnovm/stdlibs/io/io.gno
@@ -16,6 +16,8 @@ import (
 	"errors"
 )
 
+// TODO: implement rest of io package after sync package added.
+
 // Seek whence values.
 const (
 	SeekStart   = 0 // seek relative to the origin of the file
@@ -614,7 +616,12 @@ func (discard) ReadFrom(r Reader) (n int64, err error) {
 
 // NopCloser returns a ReadCloser with a no-op Close method wrapping
 // the provided Reader r.
+// If r implements WriterTo, the returned ReadCloser will also implement WriterTo
+// by forwarding the call to r.
 func NopCloser(r Reader) ReadCloser {
+	if _, ok := r.(WriterTo); ok {
+		return nopCloserWriterTo{r}
+	}
 	return nopCloser{r}
 }
 
@@ -624,6 +631,16 @@ type nopCloser struct {
 
 func (nopCloser) Close() error { return nil }
 
+type nopCloserWriterTo struct {
+	Reader
+}
+
+func (nopCloserWriterTo) Close() error { return nil }
+
+func (c *nopCloserWriterTo) WriteTo(w Writer) (n int64, err error) {
+	return c.Reader.(WriterTo).WriteTo(w)
+}
+
 // ReadAll reads from r until an error or EOF and returns the data it read.
 // A successful call returns err == nil, not err == EOF. Because ReadAll is
 // defined to read from src until EOF, it does not treat an EOF from Read
diff --git a/gnovm/stdlibs/io/io_test.gno b/gnovm/stdlibs/io/io_test.gno
index a97f6b8c075..e4f816d43ba 100644
--- a/gnovm/stdlibs/io/io_test.gno
+++ b/gnovm/stdlibs/io/io_test.gno
@@ -434,28 +434,49 @@ func TestSectionReader_Size(t *testing.T) {
 
 // largeWriter returns an invalid count that is larger than the number
 // of bytes provided (issue 39978).
-type largeWriter struct {
-	err error
-}
-
-func (w largeWriter) Write(p []byte) (int, error) {
-	return len(p) + 1, w.err
-}
-
-func TestCopyLargeWriter(t *testing.T) {
-	want := io.ErrInvalidWrite
-	rb := new(Buffer)
-	wb := largeWriter{}
-	rb.WriteString("hello, world.")
-	if _, err := io.Copy(wb, rb); err != want {
-		t.Errorf("Copy error: got %v, want %v", err, want)
-	}
-
-	want = errors.New("largeWriterError")
-	rb = new(Buffer)
-	wb = largeWriter{err: want}
-	rb.WriteString("hello, world.")
-	if _, err := io.Copy(wb, rb); err != want {
-		t.Errorf("Copy error: got %v, want %v", err, want)
+// type largeWriter struct {
+// 	err error
+// }
+
+// func (w largeWriter) Write(p []byte) (int, error) {
+// 	return len(p) + 1, w.err
+// }
+
+// func TestCopyLargeWriter(t *testing.T) {
+// 	want := io.ErrInvalidWrite
+// 	rb := new(Buffer)
+// 	wb := largeWriter{}
+// 	rb.WriteString("hello, world.")
+// 	if _, err := io.Copy(wb, rb); err != want {
+// 		t.Errorf("Copy error: got %v, want %v", err, want)
+// 	}
+
+// 	want = errors.New("largeWriterError")
+// 	rb = new(Buffer)
+// 	wb = largeWriter{err: want}
+// 	rb.WriteString("hello, world.")
+// 	if _, err := io.Copy(wb, rb); err != want {
+// 		t.Errorf("Copy error: got %v, want %v", err, want)
+// 	}
+// }
+
+func TestNopCloserWriterToForwarding(t *testing.T) {
+	for _, tc := range [...]struct {
+		Name string
+		r    Reader
+	}{
+		{"not a WriterTo", Reader(nil)},
+		{"a WriterTo", struct {
+			Reader
+			WriterTo
+		}{}},
+	} {
+		nc := NopCloser(tc.r)
+
+		_, expected := tc.r.(WriterTo)
+		_, got := nc.(WriterTo)
+		if expected != got {
+			t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected)
+		}
 	}
 }
diff --git a/gnovm/stdlibs/io/ioutil/ioutil.gno b/gnovm/stdlibs/io/ioutil/ioutil.gno
deleted file mode 100644
index 935031c0511..00000000000
--- a/gnovm/stdlibs/io/ioutil/ioutil.gno
+++ /dev/null
@@ -1,83 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package ioutil implements some I/O utility functions.
-//
-// As of Go 1.16, the same functionality is now provided
-// by package io or package os, and those implementations
-// should be preferred in new code.
-// See the specific function documentation for details.
-package ioutil
-
-import (
-	"io"
-)
-
-// ReadAll reads from r until an error or EOF and returns the data it read.
-// A successful call returns err == nil, not err == EOF. Because ReadAll is
-// defined to read from src until EOF, it does not treat an EOF from Read
-// as an error to be reported.
-//
-// As of Go 1.16, this function simply calls io.ReadAll.
-func ReadAll(r io.Reader) ([]byte, error) {
-	return io.ReadAll(r)
-}
-
-/* XXX os and os/fs removed.
-// ReadFile reads the file named by filename and returns the contents.
-// A successful call returns err == nil, not err == EOF. Because ReadFile
-// reads the whole file, it does not treat an EOF from Read as an error
-// to be reported.
-//
-// As of Go 1.16, this function simply calls os.ReadFile.
-func ReadFile(filename string) ([]byte, error) {
-	return os.ReadFile(filename)
-}
-
-// WriteFile writes data to a file named by filename.
-// If the file does not exist, WriteFile creates it with permissions perm
-// (before umask); otherwise WriteFile truncates it before writing, without changing permissions.
-//
-// As of Go 1.16, this function simply calls os.WriteFile.
-func WriteFile(filename string, data []byte, perm fs.FileMode) error {
-	return os.WriteFile(filename, data, perm)
-}
-
-// ReadDir reads the directory named by dirname and returns
-// a list of fs.FileInfo for the directory's contents,
-// sorted by filename. If an error occurs reading the directory,
-// ReadDir returns no directory entries along with the error.
-//
-// As of Go 1.16, os.ReadDir is a more efficient and correct choice:
-// it returns a list of fs.DirEntry instead of fs.FileInfo,
-// and it returns partial results in the case of an error
-// midway through reading a directory.
-func ReadDir(dirname string) ([]fs.FileInfo, error) {
-	f, err := os.Open(dirname)
-	if err != nil {
-		return nil, err
-	}
-	list, err := f.Readdir(-1)
-	f.Close()
-	if err != nil {
-		return nil, err
-	}
-	sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
-	return list, nil
-}
-*/
-
-// NopCloser returns a ReadCloser with a no-op Close method wrapping
-// the provided Reader r.
-//
-// As of Go 1.16, this function simply calls io.NopCloser.
-func NopCloser(r io.Reader) io.ReadCloser {
-	return io.NopCloser(r)
-}
-
-// Discard is an io.Writer on which all Write calls succeed
-// without doing anything.
-//
-// As of Go 1.16, this value is simply io.Discard.
-var Discard io.Writer = io.Discard

From 48a0d19a54b1270a6d4866d810391cec0495c55d Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Wed, 25 Oct 2023 00:51:04 +0900
Subject: [PATCH 04/14] fix test

---
 gnovm/stdlibs/io/io.gno                       |  4 ++++
 .../io/{io_test.gno => io_filetest.gno}       |  2 +-
 .../io/{multi_test.gno => multi_filetest.gno} |  0
 gnovm/tests/backup/ioutil.gno                 | 24 ++++++++++---------
 4 files changed, 18 insertions(+), 12 deletions(-)
 rename gnovm/stdlibs/io/{io_test.gno => io_filetest.gno} (99%)
 rename gnovm/stdlibs/io/{multi_test.gno => multi_filetest.gno} (100%)

diff --git a/gnovm/stdlibs/io/io.gno b/gnovm/stdlibs/io/io.gno
index 186f5ca9b24..1632ffb2e30 100644
--- a/gnovm/stdlibs/io/io.gno
+++ b/gnovm/stdlibs/io/io.gno
@@ -660,5 +660,9 @@ func ReadAll(r Reader) ([]byte, error) {
 			}
 			return b, err
 		}
+		if len(b) == cap(b) {
+			// Add more capacity (let append pick how much).
+			b = append(b, 0)[:len(b)]
+		}
 	}
 }
diff --git a/gnovm/stdlibs/io/io_test.gno b/gnovm/stdlibs/io/io_filetest.gno
similarity index 99%
rename from gnovm/stdlibs/io/io_test.gno
rename to gnovm/stdlibs/io/io_filetest.gno
index e4f816d43ba..a2059a004d6 100644
--- a/gnovm/stdlibs/io/io_test.gno
+++ b/gnovm/stdlibs/io/io_filetest.gno
@@ -471,7 +471,7 @@ func TestNopCloserWriterToForwarding(t *testing.T) {
 			WriterTo
 		}{}},
 	} {
-		nc := NopCloser(tc.r)
+		nc := io.NopCloser(tc.r)
 
 		_, expected := tc.r.(WriterTo)
 		_, got := nc.(WriterTo)
diff --git a/gnovm/stdlibs/io/multi_test.gno b/gnovm/stdlibs/io/multi_filetest.gno
similarity index 100%
rename from gnovm/stdlibs/io/multi_test.gno
rename to gnovm/stdlibs/io/multi_filetest.gno
diff --git a/gnovm/tests/backup/ioutil.gno b/gnovm/tests/backup/ioutil.gno
index eae22b6ea5a..e55fa4bad59 100644
--- a/gnovm/tests/backup/ioutil.gno
+++ b/gnovm/tests/backup/ioutil.gno
@@ -1,16 +1,18 @@
-package main
+// TODO: os.ReadFile is not yet implemented
 
-import (
-	"fmt"
-	"os"
-)
+// package main
 
-func main() {
-	_, err := os.ReadFile("__NotExisting__")
-	if err != nil {
-		fmt.Println(err.Error())
-	}
-}
+// import (
+// 	"fmt"
+// 	"os"
+// )
+
+// func main() {
+// 	_, err := os.ReadFile("__NotExisting__")
+// 	if err != nil {
+// 		fmt.Println(err.Error())
+// 	}
+// }
 
 // Output:
 // open __NotExisting__: no such file or directory

From 2bc5f9a0cd5c06e44f5d6bbdd64aa80827531952 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Wed, 25 Oct 2023 11:00:28 +0900
Subject: [PATCH 05/14] add itoa

---
 gnovm/stdlibs/internal/itoa/itoa.gno          | 35 ++++++++++++++++
 gnovm/stdlibs/internal/itoa/itoa_filetest.gno | 40 ++++++++++++++++++
 gnovm/stdlibs/io/io_filetest.gno              | 41 ++++++++++---------
 gnovm/tests/backup/ioutil.gno                 | 18 --------
 4 files changed, 96 insertions(+), 38 deletions(-)
 create mode 100644 gnovm/stdlibs/internal/itoa/itoa.gno
 create mode 100644 gnovm/stdlibs/internal/itoa/itoa_filetest.gno
 delete mode 100644 gnovm/tests/backup/ioutil.gno

diff --git a/gnovm/stdlibs/internal/itoa/itoa.gno b/gnovm/stdlibs/internal/itoa/itoa.gno
new file mode 100644
index 00000000000..20c7aa64528
--- /dev/null
+++ b/gnovm/stdlibs/internal/itoa/itoa.gno
@@ -0,0 +1,35 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Simple conversions to avoid depending on strconv.
+
+package itoa
+
+// Itoa converts value to a decimal string/
+func Itoa(val int) string {
+	if val < 0 {
+		return "-" + Uitoa(uint(-val))
+	}
+
+	return Uitoa(uint(val))
+}
+
+// Uitoa converts value to a decimal string.
+func Uitoa(val uint) string {
+	// avoid string allocation
+	if val == 0 {
+		return "0"
+	}
+
+	var buf [20]byte
+	for i := len(buf) - 1; val >= 10; i-- {
+		q := val
+		buf[i] = byte('0' + val - (q * 10))
+		val = 1
+	}
+
+	// val < 10
+	buf[i] = byte('0' + val)
+	return string(buf[i:])
+}
\ No newline at end of file
diff --git a/gnovm/stdlibs/internal/itoa/itoa_filetest.gno b/gnovm/stdlibs/internal/itoa/itoa_filetest.gno
new file mode 100644
index 00000000000..71931c1e3a4
--- /dev/null
+++ b/gnovm/stdlibs/internal/itoa/itoa_filetest.gno
@@ -0,0 +1,40 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package itoa_test
+
+import (
+	"fmt"
+	"internal/itoa"
+	"math"
+	"testing"
+)
+
+var (
+	minInt64  int64  = math.MinInt64
+	maxInt64  int64  = math.MaxInt64
+	maxUint64 uint64 = math.MaxUint64
+)
+
+func TestItoa(t *testing.T) {
+	tests := []int{int(minInt64), math.MinInt32, -999, -100, -1, 0, 1, 100, 999, math.MaxInt32, int(maxInt64)}
+	for _, tt := range tests {
+		got := itoa.Itoa(tt)
+		want := fmt.Sprint(tt)
+		if want != got {
+			t.Fatalf("Itoa(%d) = %s, want %s", tt, got, want)
+		}
+	}
+}
+
+func TestUitoa(t *testing.T) {
+	tests := []uint{0, 1, 100, 999, math.MaxUint32, uint(maxUint64)}
+	for _, tt := range tests {
+		got := itoa.Uitoa(tt)
+		want := fmt.Sprint(tt)
+		if want != got {
+			t.Fatalf("Uitoa(%d) = %s, want %s", tt, got, want)
+		}
+	}
+}
diff --git a/gnovm/stdlibs/io/io_filetest.gno b/gnovm/stdlibs/io/io_filetest.gno
index a2059a004d6..6ee8a2f8aac 100644
--- a/gnovm/stdlibs/io/io_filetest.gno
+++ b/gnovm/stdlibs/io/io_filetest.gno
@@ -460,23 +460,24 @@ func TestSectionReader_Size(t *testing.T) {
 // 	}
 // }
 
-func TestNopCloserWriterToForwarding(t *testing.T) {
-	for _, tc := range [...]struct {
-		Name string
-		r    Reader
-	}{
-		{"not a WriterTo", Reader(nil)},
-		{"a WriterTo", struct {
-			Reader
-			WriterTo
-		}{}},
-	} {
-		nc := io.NopCloser(tc.r)
-
-		_, expected := tc.r.(WriterTo)
-		_, got := nc.(WriterTo)
-		if expected != got {
-			t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected)
-		}
-	}
-}
+// XXX
+// func TestNopCloserWriterToForwarding(t *testing.T) {
+// 	for _, tc := range [...]struct {
+// 		Name string
+// 		r    Reader
+// 	}{
+// 		{"not a WriterTo", Reader(nil)},
+// 		{"a WriterTo", struct {
+// 			Reader
+// 			WriterTo
+// 		}{}},
+// 	} {
+// 		nc := io.NopCloser(tc.r)
+
+// 		_, expected := tc.r.(WriterTo)
+// 		_, got := nc.(WriterTo)
+// 		if expected != got {
+// 			t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected)
+// 		}
+// 	}
+// }
diff --git a/gnovm/tests/backup/ioutil.gno b/gnovm/tests/backup/ioutil.gno
deleted file mode 100644
index e55fa4bad59..00000000000
--- a/gnovm/tests/backup/ioutil.gno
+++ /dev/null
@@ -1,18 +0,0 @@
-// TODO: os.ReadFile is not yet implemented
-
-// package main
-
-// import (
-// 	"fmt"
-// 	"os"
-// )
-
-// func main() {
-// 	_, err := os.ReadFile("__NotExisting__")
-// 	if err != nil {
-// 		fmt.Println(err.Error())
-// 	}
-// }
-
-// Output:
-// open __NotExisting__: no such file or directory

From e8c88014746655aaa771db0d3d07969eb0025b9c Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Wed, 25 Oct 2023 11:02:47 +0900
Subject: [PATCH 06/14] fmt

---
 gnovm/stdlibs/internal/itoa/itoa.gno          | 2 +-
 gnovm/stdlibs/internal/itoa/itoa_filetest.gno | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/gnovm/stdlibs/internal/itoa/itoa.gno b/gnovm/stdlibs/internal/itoa/itoa.gno
index 20c7aa64528..4eb009e7c5f 100644
--- a/gnovm/stdlibs/internal/itoa/itoa.gno
+++ b/gnovm/stdlibs/internal/itoa/itoa.gno
@@ -32,4 +32,4 @@ func Uitoa(val uint) string {
 	// val < 10
 	buf[i] = byte('0' + val)
 	return string(buf[i:])
-}
\ No newline at end of file
+}
diff --git a/gnovm/stdlibs/internal/itoa/itoa_filetest.gno b/gnovm/stdlibs/internal/itoa/itoa_filetest.gno
index 71931c1e3a4..6a2feafd173 100644
--- a/gnovm/stdlibs/internal/itoa/itoa_filetest.gno
+++ b/gnovm/stdlibs/internal/itoa/itoa_filetest.gno
@@ -6,9 +6,10 @@ package itoa_test
 
 import (
 	"fmt"
-	"internal/itoa"
 	"math"
 	"testing"
+
+	"internal/itoa"
 )
 
 var (

From 3fef17d6bf1f0e5ed0c951d480a3cc6e86659595 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Wed, 25 Oct 2023 15:00:18 +0900
Subject: [PATCH 07/14] update io

---
 gnovm/stdlibs/io/example_test.gno             |  2 +-
 gnovm/stdlibs/io/io.gno                       | 56 +++++++++++++
 .../io/{io_filetest.gno => io_test.gno}       | 81 ++++++++++++++++---
 .../io/{multi_filetest.gno => multi_test.gno} |  4 +-
 4 files changed, 130 insertions(+), 13 deletions(-)
 rename gnovm/stdlibs/io/{io_filetest.gno => io_test.gno} (84%)
 rename gnovm/stdlibs/io/{multi_filetest.gno => multi_test.gno} (99%)

diff --git a/gnovm/stdlibs/io/example_test.gno b/gnovm/stdlibs/io/example_test.gno
index c781fb9166e..edd13be523a 100644
--- a/gnovm/stdlibs/io/example_test.gno
+++ b/gnovm/stdlibs/io/example_test.gno
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package io_test
+package io
 
 import (
 	"bytes"
diff --git a/gnovm/stdlibs/io/io.gno b/gnovm/stdlibs/io/io.gno
index 1632ffb2e30..7222238373a 100644
--- a/gnovm/stdlibs/io/io.gno
+++ b/gnovm/stdlibs/io/io.gno
@@ -479,6 +479,15 @@ func (l *LimitedReader) Read(p []byte) (n int, err error) {
 // NewSectionReader returns a SectionReader that reads from r
 // starting at offset off and stops with EOF after n bytes.
 func NewSectionReader(r ReaderAt, off int64, n int64) *SectionReader {
+	var remaining int64
+	const maxInt64 = 1<<63 - 1
+	if off <= maxInt64-n {
+		remaining = n + off
+	} else {
+		// Overflow, with no way to return error.
+		// Assume we can read up to an offset of `1<<63 - 1` bytes in this case.
+		remaining = maxInt64
+	}
 	return &SectionReader{r, off, off, off + n}
 }
 
@@ -545,6 +554,53 @@ func (s *SectionReader) ReadAt(p []byte, off int64) (n int, err error) {
 // Size returns the size of the section in bytes.
 func (s *SectionReader) Size() int64 { return s.limit - s.base }
 
+// And OffsetWriter maps writers at offset base to offset base + off in the underlying writer.
+type OffsetWriter struct {
+	w    WriterAt
+	base int64 // the original offset
+	off  int64 // the current offset
+}
+
+// NewOffsetWriter returns a new OffsetWriter that writes to w starting at offset off.
+func NewOffsetWriter(w WriterAt, off int64) *OffsetWriter {
+	return &OffsetWriter{w: w, off: off}
+}
+
+func (o *OffsetWriter) Write(p []byte) (n int, err error) {
+	// n, err = o.w.WriterAt(p, o.off)
+	wa := o.w
+	n, err = wa.WriteAt(p, o.off)
+	o.off += int64(n)
+	return
+}
+
+func (o *OffsetWriter) WriteAt(p []byte, off int64) (n int, err error) {
+	if off < 0 {
+		return 0, errOffset
+	}
+
+	off += o.base
+	return o.w.WriteAt(p, off)
+}
+
+func (o *OffsetWriter) Seek(offset int64, whence int) (int64, error) {
+	switch whence {
+	default:
+		return 0, errWhence
+	case SeekStart:
+		offset += o.base
+	case SeekCurrent:
+		offset += o.off
+	}
+	
+	if offset < o.base {
+		return 0, errOffset
+	}
+
+	o.off = offset
+	return offset - o.base, nil
+}
+
 // TeeReader returns a Reader that writes to w what it reads from r.
 // All reads from r performed through it are matched with
 // corresponding writes to w. There is no internal buffering -
diff --git a/gnovm/stdlibs/io/io_filetest.gno b/gnovm/stdlibs/io/io_test.gno
similarity index 84%
rename from gnovm/stdlibs/io/io_filetest.gno
rename to gnovm/stdlibs/io/io_test.gno
index 6ee8a2f8aac..02570967175 100644
--- a/gnovm/stdlibs/io/io_filetest.gno
+++ b/gnovm/stdlibs/io/io_test.gno
@@ -1,9 +1,9 @@
+package io
+
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package io_test
-
 import (
 	"bytes"
 	"errors"
@@ -460,24 +460,85 @@ func TestSectionReader_Size(t *testing.T) {
 // 	}
 // }
 
-// XXX
+// TODO fix this
 // func TestNopCloserWriterToForwarding(t *testing.T) {
 // 	for _, tc := range [...]struct {
 // 		Name string
-// 		r    Reader
+// 		r    io.Reader
 // 	}{
-// 		{"not a WriterTo", Reader(nil)},
+// 		{"not a WriterTo", io.Reader(nil)},
 // 		{"a WriterTo", struct {
-// 			Reader
-// 			WriterTo
+// 			io.Reader
+// 			io.WriterTo
 // 		}{}},
 // 	} {
-// 		nc := io.NopCloser(tc.r)
+// 		nc := NopCloser(tc.r)
 
-// 		_, expected := tc.r.(WriterTo)
-// 		_, got := nc.(WriterTo)
+// 		_, expected := tc.r.(io.WriterTo)
+// 		_, got := nc.(io.WriterTo)
 // 		if expected != got {
 // 			t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected)
 // 		}
 // 	}
 // }
+
+// XXX os.CreateTemp is not available for now
+//
+// func TestOffsetWriter_Seek(t *testing.T) {
+// 	tmpfilename := "TestOffsetWriter_Seek"
+// 	tmpfile, err := os.CreateTemp(t.TempDir(), tmpfilename)
+// 	if err != nil || tmpfile == nil {
+// 		t.Fatalf("CreateTemp(%s) failed: %v", tmpfilename, err)
+// 	}
+// 	defer tmpfile.Close()
+// 	w := NewOffsetWriter(tmpfile, 0)
+
+// 	// Should throw error errWhence if whence is not valid
+// 	t.Run("errWhence", func(t *testing.T) {
+// 		for _, whence := range []int{-3, -2, -1, 3, 4, 5} {
+// 			var offset int64 = 0
+// 			gotOff, gotErr := w.Seek(offset, whence)
+// 			if gotOff != 0 || gotErr != ErrWhence {
+// 				t.Errorf("For whence %d, offset %d, OffsetWriter.Seek got: (%d, %v), want: (%d, %v)",
+// 					whence, offset, gotOff, gotErr, 0, ErrWhence)
+// 			}
+// 		}
+// 	})
+
+// 	// Should throw error errOffset if offset is negative
+// 	t.Run("errOffset", func(t *testing.T) {
+// 		for _, whence := range []int{SeekStart, SeekCurrent} {
+// 			for offset := int64(-3); offset < 0; offset++ {
+// 				gotOff, gotErr := w.Seek(offset, whence)
+// 				if gotOff != 0 || gotErr != ErrOffset {
+// 					t.Errorf("For whence %d, offset %d, OffsetWriter.Seek got: (%d, %v), want: (%d, %v)",
+// 						whence, offset, gotOff, gotErr, 0, ErrOffset)
+// 				}
+// 			}
+// 		}
+// 	})
+
+// 	// Normal tests
+// 	t.Run("normal", func(t *testing.T) {
+// 		tests := []struct {
+// 			offset    int64
+// 			whence    int
+// 			returnOff int64
+// 		}{
+// 			// keep in order
+// 			{whence: SeekStart, offset: 1, returnOff: 1},
+// 			{whence: SeekStart, offset: 2, returnOff: 2},
+// 			{whence: SeekStart, offset: 3, returnOff: 3},
+// 			{whence: SeekCurrent, offset: 1, returnOff: 4},
+// 			{whence: SeekCurrent, offset: 2, returnOff: 6},
+// 			{whence: SeekCurrent, offset: 3, returnOff: 9},
+// 		}
+// 		for idx, tt := range tests {
+// 			gotOff, gotErr := w.Seek(tt.offset, tt.whence)
+// 			if gotOff != tt.returnOff || gotErr != nil {
+// 				t.Errorf("%d:: For whence %d, offset %d, OffsetWriter.Seek got: (%d, %v), want: (%d, <nil>)",
+// 					idx+1, tt.whence, tt.offset, gotOff, gotErr, tt.returnOff)
+// 			}
+// 		}
+// 	})
+// }
diff --git a/gnovm/stdlibs/io/multi_filetest.gno b/gnovm/stdlibs/io/multi_test.gno
similarity index 99%
rename from gnovm/stdlibs/io/multi_filetest.gno
rename to gnovm/stdlibs/io/multi_test.gno
index ee800b3ec24..e1f6f1d3a03 100644
--- a/gnovm/stdlibs/io/multi_filetest.gno
+++ b/gnovm/stdlibs/io/multi_test.gno
@@ -1,9 +1,9 @@
+package io
+
 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package io_test
-
 import (
 	"bytes"
 	"crypto/sha1"

From 0a5087d07841e6a608540f51081975bf12e638ca Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Thu, 26 Oct 2023 10:24:42 +0900
Subject: [PATCH 08/14] change io0 file name

---
 gnovm/stdlibs/io/io.gno                    | 2 +-
 gnovm/tests/files/{ioutil0.gno => io2.gno} | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)
 rename gnovm/tests/files/{ioutil0.gno => io2.gno} (88%)

diff --git a/gnovm/stdlibs/io/io.gno b/gnovm/stdlibs/io/io.gno
index 7222238373a..3c6c2093edc 100644
--- a/gnovm/stdlibs/io/io.gno
+++ b/gnovm/stdlibs/io/io.gno
@@ -592,7 +592,7 @@ func (o *OffsetWriter) Seek(offset int64, whence int) (int64, error) {
 	case SeekCurrent:
 		offset += o.off
 	}
-	
+
 	if offset < o.base {
 		return 0, errOffset
 	}
diff --git a/gnovm/tests/files/ioutil0.gno b/gnovm/tests/files/io2.gno
similarity index 88%
rename from gnovm/tests/files/ioutil0.gno
rename to gnovm/tests/files/io2.gno
index 800d237be22..24655f5040c 100644
--- a/gnovm/tests/files/ioutil0.gno
+++ b/gnovm/tests/files/io2.gno
@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"strings"
 )
@@ -10,7 +10,7 @@ import (
 func main() {
 	r := strings.NewReader("Go is a general-purpose language designed with systems programming in mind.")
 
-	b, err := ioutil.ReadAll(r)
+	b, err := io.ReadAll(r)
 	if err != nil {
 		log.Fatal(err)
 	}

From 54d5b1161d188ad7d0641de3bff054ef2e94b822 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Thu, 26 Oct 2023 10:41:13 +0900
Subject: [PATCH 09/14] update 558b issue file

---
 gnovm/tests/files/issue-558b.gno | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gnovm/tests/files/issue-558b.gno b/gnovm/tests/files/issue-558b.gno
index 686c73b5c88..55eba88c985 100644
--- a/gnovm/tests/files/issue-558b.gno
+++ b/gnovm/tests/files/issue-558b.gno
@@ -3,7 +3,7 @@ package main
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io"
 	"log"
 	"strings"
 )
@@ -36,7 +36,7 @@ type pipe struct {
 
 func newReadAutoCloser(r io.Reader) readAutoCloser {
 	if _, ok := r.(io.Closer); !ok {
-		return readAutoCloser{ioutil.NopCloser(r)}
+		return readAutoCloser{io.NopCloser(r)}
 	}
 	return readAutoCloser{r.(io.ReadCloser)}
 }

From 15c277f87b3fd8b7ef05c24c4edf2cdcb1b0aca9 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Fri, 27 Oct 2023 09:51:10 +0900
Subject: [PATCH 10/14] modified to reflect review

---
 gnovm/stdlibs/internal/itoa/itoa.gno          | 35 ----------------
 gnovm/stdlibs/internal/itoa/itoa_filetest.gno | 41 -------------------
 gnovm/stdlibs/io/example_test.gno             |  2 +-
 gnovm/stdlibs/io/io.gno                       |  2 +-
 gnovm/stdlibs/io/io_test.gno                  |  2 +-
 gnovm/stdlibs/io/multi_test.gno               |  2 +-
 6 files changed, 4 insertions(+), 80 deletions(-)
 delete mode 100644 gnovm/stdlibs/internal/itoa/itoa.gno
 delete mode 100644 gnovm/stdlibs/internal/itoa/itoa_filetest.gno

diff --git a/gnovm/stdlibs/internal/itoa/itoa.gno b/gnovm/stdlibs/internal/itoa/itoa.gno
deleted file mode 100644
index 4eb009e7c5f..00000000000
--- a/gnovm/stdlibs/internal/itoa/itoa.gno
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Simple conversions to avoid depending on strconv.
-
-package itoa
-
-// Itoa converts value to a decimal string/
-func Itoa(val int) string {
-	if val < 0 {
-		return "-" + Uitoa(uint(-val))
-	}
-
-	return Uitoa(uint(val))
-}
-
-// Uitoa converts value to a decimal string.
-func Uitoa(val uint) string {
-	// avoid string allocation
-	if val == 0 {
-		return "0"
-	}
-
-	var buf [20]byte
-	for i := len(buf) - 1; val >= 10; i-- {
-		q := val
-		buf[i] = byte('0' + val - (q * 10))
-		val = 1
-	}
-
-	// val < 10
-	buf[i] = byte('0' + val)
-	return string(buf[i:])
-}
diff --git a/gnovm/stdlibs/internal/itoa/itoa_filetest.gno b/gnovm/stdlibs/internal/itoa/itoa_filetest.gno
deleted file mode 100644
index 6a2feafd173..00000000000
--- a/gnovm/stdlibs/internal/itoa/itoa_filetest.gno
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package itoa_test
-
-import (
-	"fmt"
-	"math"
-	"testing"
-
-	"internal/itoa"
-)
-
-var (
-	minInt64  int64  = math.MinInt64
-	maxInt64  int64  = math.MaxInt64
-	maxUint64 uint64 = math.MaxUint64
-)
-
-func TestItoa(t *testing.T) {
-	tests := []int{int(minInt64), math.MinInt32, -999, -100, -1, 0, 1, 100, 999, math.MaxInt32, int(maxInt64)}
-	for _, tt := range tests {
-		got := itoa.Itoa(tt)
-		want := fmt.Sprint(tt)
-		if want != got {
-			t.Fatalf("Itoa(%d) = %s, want %s", tt, got, want)
-		}
-	}
-}
-
-func TestUitoa(t *testing.T) {
-	tests := []uint{0, 1, 100, 999, math.MaxUint32, uint(maxUint64)}
-	for _, tt := range tests {
-		got := itoa.Uitoa(tt)
-		want := fmt.Sprint(tt)
-		if want != got {
-			t.Fatalf("Uitoa(%d) = %s, want %s", tt, got, want)
-		}
-	}
-}
diff --git a/gnovm/stdlibs/io/example_test.gno b/gnovm/stdlibs/io/example_test.gno
index edd13be523a..c781fb9166e 100644
--- a/gnovm/stdlibs/io/example_test.gno
+++ b/gnovm/stdlibs/io/example_test.gno
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package io
+package io_test
 
 import (
 	"bytes"
diff --git a/gnovm/stdlibs/io/io.gno b/gnovm/stdlibs/io/io.gno
index 3c6c2093edc..499449cc729 100644
--- a/gnovm/stdlibs/io/io.gno
+++ b/gnovm/stdlibs/io/io.gno
@@ -554,7 +554,7 @@ func (s *SectionReader) ReadAt(p []byte, off int64) (n int, err error) {
 // Size returns the size of the section in bytes.
 func (s *SectionReader) Size() int64 { return s.limit - s.base }
 
-// And OffsetWriter maps writers at offset base to offset base + off in the underlying writer.
+// An OffsetWriter maps writers at offset base to offset base + off in the underlying writer.
 type OffsetWriter struct {
 	w    WriterAt
 	base int64 // the original offset
diff --git a/gnovm/stdlibs/io/io_test.gno b/gnovm/stdlibs/io/io_test.gno
index 02570967175..939560026b2 100644
--- a/gnovm/stdlibs/io/io_test.gno
+++ b/gnovm/stdlibs/io/io_test.gno
@@ -1,4 +1,4 @@
-package io
+package io_test
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/gnovm/stdlibs/io/multi_test.gno b/gnovm/stdlibs/io/multi_test.gno
index e1f6f1d3a03..31345279318 100644
--- a/gnovm/stdlibs/io/multi_test.gno
+++ b/gnovm/stdlibs/io/multi_test.gno
@@ -1,4 +1,4 @@
-package io
+package io_test
 
 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

From 4435a1956c7b94cd098a94c17322ea14122bdb9b Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Fri, 27 Oct 2023 10:30:53 +0900
Subject: [PATCH 11/14] fix io and its tests

---
 gnovm/stdlibs/io/export_test.gno |  6 ++-
 gnovm/stdlibs/io/io.gno          |  6 +--
 gnovm/stdlibs/io/io_test.gno     | 87 ++++++++++++++++----------------
 3 files changed, 51 insertions(+), 48 deletions(-)

diff --git a/gnovm/stdlibs/io/export_test.gno b/gnovm/stdlibs/io/export_test.gno
index fa3e8e76f61..6204ffc4591 100644
--- a/gnovm/stdlibs/io/export_test.gno
+++ b/gnovm/stdlibs/io/export_test.gno
@@ -5,4 +5,8 @@
 package io
 
 // exported for test
-var ErrInvalidWrite = errInvalidWrite
+var (
+	ErrInvalidWrite = errInvalidWrite
+	ErrWhence       = errWhence
+	ErrOffset       = errOffset
+)
diff --git a/gnovm/stdlibs/io/io.gno b/gnovm/stdlibs/io/io.gno
index 499449cc729..6ee52cfe293 100644
--- a/gnovm/stdlibs/io/io.gno
+++ b/gnovm/stdlibs/io/io.gno
@@ -672,8 +672,8 @@ func (discard) ReadFrom(r Reader) (n int64, err error) {
 
 // NopCloser returns a ReadCloser with a no-op Close method wrapping
 // the provided Reader r.
-// If r implements WriterTo, the returned ReadCloser will also implement WriterTo
-// by forwarding the call to r.
+// If r implements WriterTo, the returned ReadCloser will implement WriterTo
+// by forwarding calls to r.
 func NopCloser(r Reader) ReadCloser {
 	if _, ok := r.(WriterTo); ok {
 		return nopCloserWriterTo{r}
@@ -693,7 +693,7 @@ type nopCloserWriterTo struct {
 
 func (nopCloserWriterTo) Close() error { return nil }
 
-func (c *nopCloserWriterTo) WriteTo(w Writer) (n int64, err error) {
+func (c nopCloserWriterTo) WriteTo(w Writer) (n int64, err error) {
 	return c.Reader.(WriterTo).WriteTo(w)
 }
 
diff --git a/gnovm/stdlibs/io/io_test.gno b/gnovm/stdlibs/io/io_test.gno
index 939560026b2..914edfbf0c7 100644
--- a/gnovm/stdlibs/io/io_test.gno
+++ b/gnovm/stdlibs/io/io_test.gno
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 	"strings"
 	"testing"
 )
@@ -434,56 +435,54 @@ func TestSectionReader_Size(t *testing.T) {
 
 // largeWriter returns an invalid count that is larger than the number
 // of bytes provided (issue 39978).
-// type largeWriter struct {
-// 	err error
-// }
+type largeWriter struct {
+	err error
+}
 
-// func (w largeWriter) Write(p []byte) (int, error) {
-// 	return len(p) + 1, w.err
-// }
+func (w largeWriter) Write(p []byte) (int, error) {
+	return len(p) + 1, w.err
+}
 
-// func TestCopyLargeWriter(t *testing.T) {
-// 	want := io.ErrInvalidWrite
-// 	rb := new(Buffer)
-// 	wb := largeWriter{}
-// 	rb.WriteString("hello, world.")
-// 	if _, err := io.Copy(wb, rb); err != want {
-// 		t.Errorf("Copy error: got %v, want %v", err, want)
-// 	}
+func TestCopyLargeWriter(t *testing.T) {
+	want := errInvalidWrite
+	rb := new(Buffer)
+	wb := largeWriter{}
+	rb.WriteString("hello, world.")
+	if _, err := Copy(wb, rb); err != want {
+		t.Errorf("Copy error: got %v, want %v", err, want)
+	}
 
-// 	want = errors.New("largeWriterError")
-// 	rb = new(Buffer)
-// 	wb = largeWriter{err: want}
-// 	rb.WriteString("hello, world.")
-// 	if _, err := io.Copy(wb, rb); err != want {
-// 		t.Errorf("Copy error: got %v, want %v", err, want)
-// 	}
-// }
+	want = errors.New("largeWriterError")
+	rb = new(Buffer)
+	wb = largeWriter{err: want}
+	rb.WriteString("hello, world.")
+	if _, err := Copy(wb, rb); err != want {
+		t.Errorf("Copy error: got %v, want %v", err, want)
+	}
+}
 
-// TODO fix this
-// func TestNopCloserWriterToForwarding(t *testing.T) {
-// 	for _, tc := range [...]struct {
-// 		Name string
-// 		r    io.Reader
-// 	}{
-// 		{"not a WriterTo", io.Reader(nil)},
-// 		{"a WriterTo", struct {
-// 			io.Reader
-// 			io.WriterTo
-// 		}{}},
-// 	} {
-// 		nc := NopCloser(tc.r)
-
-// 		_, expected := tc.r.(io.WriterTo)
-// 		_, got := nc.(io.WriterTo)
-// 		if expected != got {
-// 			t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected)
-// 		}
-// 	}
-// }
+func TestNopCloserWriterToForwarding(t *testing.T) {
+	for _, tc := range [...]struct {
+		Name string
+		r    Reader
+	}{
+		{"not a WriterTo", Reader(nil)},
+		{"a WriterTo", struct {
+			Reader
+			WriterTo
+		}{}},
+	} {
+		nc := NopCloser(tc.r)
+
+		_, expected := tc.r.(WriterTo)
+		_, got := nc.(WriterTo)
+		if expected != got {
+			t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected)
+		}
+	}
+}
 
 // XXX os.CreateTemp is not available for now
-//
 // func TestOffsetWriter_Seek(t *testing.T) {
 // 	tmpfilename := "TestOffsetWriter_Seek"
 // 	tmpfile, err := os.CreateTemp(t.TempDir(), tmpfilename)

From d6f29c01a8a8fcd894a0fd1c45b1bc3795887489 Mon Sep 17 00:00:00 2001
From: Lee ByeongJun <lbj199874@gmail.com>
Date: Tue, 31 Oct 2023 00:06:06 +0900
Subject: [PATCH 12/14] remove `ioutil` from gno files and imports.go

---
 gnovm/tests/backup/cli1.gno        | 4 ++--
 gnovm/tests/backup/cli2.gno        | 4 ++--
 gnovm/tests/backup/cli3.gno        | 4 ++--
 gnovm/tests/backup/cli4.gno        | 4 ++--
 gnovm/tests/backup/cli5.gno        | 4 ++--
 gnovm/tests/backup/cli6.gno        | 4 ++--
 gnovm/tests/backup/file_access.gno | 5 ++---
 gnovm/tests/backup/issue-558.gno   | 6 +++---
 gnovm/tests/imports.go             | 6 ------
 9 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/gnovm/tests/backup/cli1.gno b/gnovm/tests/backup/cli1.gno
index 8eb9e8c40d7..843eb461ac2 100644
--- a/gnovm/tests/backup/cli1.gno
+++ b/gnovm/tests/backup/cli1.gno
@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net"
 	"net/http"
@@ -13,7 +13,7 @@ func client(uri string) {
 	if err != nil {
 		log.Fatal(err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/gnovm/tests/backup/cli2.gno b/gnovm/tests/backup/cli2.gno
index a9e8e53be3a..0be01d2f1a9 100644
--- a/gnovm/tests/backup/cli2.gno
+++ b/gnovm/tests/backup/cli2.gno
@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net"
 	"net/http"
@@ -21,7 +21,7 @@ func client(uri string) {
 	if err != nil {
 		log.Fatal(err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/gnovm/tests/backup/cli3.gno b/gnovm/tests/backup/cli3.gno
index 1c696d4bc4c..50b11b9e4c3 100644
--- a/gnovm/tests/backup/cli3.gno
+++ b/gnovm/tests/backup/cli3.gno
@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -13,7 +13,7 @@ func client(uri string) {
 	if err != nil {
 		log.Fatal(err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/gnovm/tests/backup/cli4.gno b/gnovm/tests/backup/cli4.gno
index 147b63c3e6e..aab6405917c 100644
--- a/gnovm/tests/backup/cli4.gno
+++ b/gnovm/tests/backup/cli4.gno
@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -40,7 +40,7 @@ func client(uri string) {
 	if err != nil {
 		log.Fatal(err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/gnovm/tests/backup/cli5.gno b/gnovm/tests/backup/cli5.gno
index a2e1787c996..6b536841a6d 100644
--- a/gnovm/tests/backup/cli5.gno
+++ b/gnovm/tests/backup/cli5.gno
@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -40,7 +40,7 @@ func client(uri string) {
 	if err != nil {
 		log.Fatal(err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/gnovm/tests/backup/cli6.gno b/gnovm/tests/backup/cli6.gno
index 89ae9f8b98d..e97da82736e 100644
--- a/gnovm/tests/backup/cli6.gno
+++ b/gnovm/tests/backup/cli6.gno
@@ -2,7 +2,7 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -41,7 +41,7 @@ func client(uri string) {
 	if err != nil {
 		log.Fatal(err)
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/gnovm/tests/backup/file_access.gno b/gnovm/tests/backup/file_access.gno
index 6d750c44a36..e81cc6a0bee 100644
--- a/gnovm/tests/backup/file_access.gno
+++ b/gnovm/tests/backup/file_access.gno
@@ -2,12 +2,11 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
-	"os"
+	"io"
 )
 
 func main() {
-	file, err := ioutil.TempFile("", "yeagibench")
+	file, err := io.TempFile("", "yeagibench")
 	if err != nil {
 		panic(err)
 	}
diff --git a/gnovm/tests/backup/issue-558.gno b/gnovm/tests/backup/issue-558.gno
index d36bb4e18a7..e99566f7634 100644
--- a/gnovm/tests/backup/issue-558.gno
+++ b/gnovm/tests/backup/issue-558.gno
@@ -4,7 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io"
 	"log"
 	"strings"
 )
@@ -37,7 +37,7 @@ type pipe struct {
 
 func newReadAutoCloser(r io.Reader) readAutoCloser {
 	if _, ok := r.(io.Closer); !ok {
-		return readAutoCloser{ioutil.NopCloser(r)}
+		return readAutoCloser{io.NopCloser(r)}
 	}
 	return readAutoCloser{r.(io.ReadCloser)}
 }
@@ -45,7 +45,7 @@ func newReadAutoCloser(r io.Reader) readAutoCloser {
 func main() {
 	p := &pipe{}
 	p.Reader = newReadAutoCloser(strings.NewReader("test"))
-	b, err := ioutil.ReadAll(p.Reader)
+	b, err := io.ReadAll(p.Reader)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/gnovm/tests/imports.go b/gnovm/tests/imports.go
index fc2820ce00e..3bdc9722ab1 100644
--- a/gnovm/tests/imports.go
+++ b/gnovm/tests/imports.go
@@ -20,7 +20,6 @@ import (
 	"image"
 	"image/color"
 	"io"
-	"io/ioutil"
 	"log"
 	"math"
 	"math/big"
@@ -361,11 +360,6 @@ func TestStore(rootDir, filesPath string, stdin io.Reader, stdout, stderr io.Wri
 				pkg.DefineGoNativeType(reflect.TypeOf((*io.Closer)(nil)).Elem())
 				pkg.DefineGoNativeType(reflect.TypeOf((*io.Reader)(nil)).Elem())
 				return pkg, pkg.NewPackage()
-			case "io/ioutil":
-				pkg := gno.NewPackageNode("ioutil", pkgPath, nil)
-				pkg.DefineGoNativeValue("NopCloser", ioutil.NopCloser)
-				pkg.DefineGoNativeValue("ReadAll", ioutil.ReadAll)
-				return pkg, pkg.NewPackage()
 			case "log":
 				pkg := gno.NewPackageNode("log", pkgPath, nil)
 				pkg.DefineGoNativeValue("Fatal", log.Fatal)

From e83663ccd1788ae8cee674568b052809440419cf Mon Sep 17 00:00:00 2001
From: Morgan Bazalgette <morgan@morganbaz.com>
Date: Tue, 7 Nov 2023 23:06:10 +0100
Subject: [PATCH 13/14] add nopcloser and readall to tests/imports.go

---
 gnovm/tests/imports.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gnovm/tests/imports.go b/gnovm/tests/imports.go
index 3bdc9722ab1..0741d0b466a 100644
--- a/gnovm/tests/imports.go
+++ b/gnovm/tests/imports.go
@@ -355,7 +355,9 @@ func TestStore(rootDir, filesPath string, stdin io.Reader, stdout, stderr io.Wri
 			case "io":
 				pkg := gno.NewPackageNode("io", pkgPath, nil)
 				pkg.DefineGoNativeValue("EOF", io.EOF)
+				pkg.DefineGoNativeValue("NopCloser", io.NopCloser)
 				pkg.DefineGoNativeValue("ReadFull", io.ReadFull)
+				pkg.DefineGoNativeValue("ReadAll", io.ReadAll)
 				pkg.DefineGoNativeType(reflect.TypeOf((*io.ReadCloser)(nil)).Elem())
 				pkg.DefineGoNativeType(reflect.TypeOf((*io.Closer)(nil)).Elem())
 				pkg.DefineGoNativeType(reflect.TypeOf((*io.Reader)(nil)).Elem())

From 33daa49726bcbc6692a06609ea37bc29c4fec1dd Mon Sep 17 00:00:00 2001
From: Morgan Bazalgette <morgan@morganbaz.com>
Date: Tue, 7 Nov 2023 23:26:05 +0100
Subject: [PATCH 14/14] fix test pkg0

---
 gnovm/stdlibs/io/io_test.gno | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/gnovm/stdlibs/io/io_test.gno b/gnovm/stdlibs/io/io_test.gno
index 914edfbf0c7..613b7d13e35 100644
--- a/gnovm/stdlibs/io/io_test.gno
+++ b/gnovm/stdlibs/io/io_test.gno
@@ -444,11 +444,11 @@ func (w largeWriter) Write(p []byte) (int, error) {
 }
 
 func TestCopyLargeWriter(t *testing.T) {
-	want := errInvalidWrite
+	want := io.ErrInvalidWrite
 	rb := new(Buffer)
 	wb := largeWriter{}
 	rb.WriteString("hello, world.")
-	if _, err := Copy(wb, rb); err != want {
+	if _, err := io.Copy(wb, rb); err != want {
 		t.Errorf("Copy error: got %v, want %v", err, want)
 	}
 
@@ -456,7 +456,7 @@ func TestCopyLargeWriter(t *testing.T) {
 	rb = new(Buffer)
 	wb = largeWriter{err: want}
 	rb.WriteString("hello, world.")
-	if _, err := Copy(wb, rb); err != want {
+	if _, err := io.Copy(wb, rb); err != want {
 		t.Errorf("Copy error: got %v, want %v", err, want)
 	}
 }
@@ -464,18 +464,18 @@ func TestCopyLargeWriter(t *testing.T) {
 func TestNopCloserWriterToForwarding(t *testing.T) {
 	for _, tc := range [...]struct {
 		Name string
-		r    Reader
+		r    io.Reader
 	}{
-		{"not a WriterTo", Reader(nil)},
+		{"not a WriterTo", io.Reader(nil)},
 		{"a WriterTo", struct {
-			Reader
-			WriterTo
+			io.Reader
+			io.WriterTo
 		}{}},
 	} {
-		nc := NopCloser(tc.r)
+		nc := io.NopCloser(tc.r)
 
-		_, expected := tc.r.(WriterTo)
-		_, got := nc.(WriterTo)
+		_, expected := tc.r.(io.WriterTo)
+		_, got := nc.(io.WriterTo)
 		if expected != got {
 			t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected)
 		}