all: update references to symbols moved from io/ioutil to io

The old ioutil references are still valid, but update our code
to reflect best practices and get used to the new locations.

Code compiled with the bootstrap toolchain
(cmd/asm, cmd/dist, cmd/compile, debug/elf)
must remain Go 1.4-compatible and is excluded.
Also excluded vendored code.

For #41190.

Change-Id: I6d86f2bf7bc37a9d904b6cee3fe0c7af6d94d5b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/263142
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

9 files changed, 28 insertions, 34 deletions

diff --git a/src/encoding/ascii85/ascii85_test.go b/src/encoding/ascii85/ascii85_test.go
index 1a3a87a596..c637103942 100644
--- a/src/encoding/ascii85/ascii85_test.go
+++ b/src/encoding/ascii85/ascii85_test.go
@@ -7,7 +7,6 @@ package ascii85
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"strings"
 	"testing"
 )
@@ -118,7 +117,7 @@ func TestDecode(t *testing.T) {
 func TestDecoder(t *testing.T) {
 	for _, p := range pairs {
 		decoder := NewDecoder(strings.NewReader(p.encoded))
-		dbuf, err := ioutil.ReadAll(decoder)
+		dbuf, err := io.ReadAll(decoder)
 		if err != nil {
 			t.Fatal("Read failed", err)
 		}
@@ -187,7 +186,7 @@ func TestBig(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Encoder.Close() = %v want nil", err)
 	}
-	decoded, err := ioutil.ReadAll(NewDecoder(encoded))
+	decoded, err := io.ReadAll(NewDecoder(encoded))
 	if err != nil {
 		t.Fatalf("io.ReadAll(NewDecoder(...)): %v", err)
 	}
@@ -205,7 +204,7 @@ func TestBig(t *testing.T) {
 
 func TestDecoderInternalWhitespace(t *testing.T) {
 	s := strings.Repeat(" ", 2048) + "z"
-	decoded, err := ioutil.ReadAll(NewDecoder(strings.NewReader(s)))
+	decoded, err := io.ReadAll(NewDecoder(strings.NewReader(s)))
 	if err != nil {
 		t.Errorf("Decode gave error %v", err)
 	}
diff --git a/src/encoding/base32/base32_test.go b/src/encoding/base32/base32_test.go
index 0b611db0b2..8fb22b9078 100644
--- a/src/encoding/base32/base32_test.go
+++ b/src/encoding/base32/base32_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"errors"
 	"io"
-	"io/ioutil"
 	"strings"
 	"testing"
 )
@@ -361,9 +360,9 @@ func TestBig(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Encoder.Close() = %v want nil", err)
 	}
-	decoded, err := ioutil.ReadAll(NewDecoder(StdEncoding, encoded))
+	decoded, err := io.ReadAll(NewDecoder(StdEncoding, encoded))
 	if err != nil {
-		t.Fatalf("ioutil.ReadAll(NewDecoder(...)): %v", err)
+		t.Fatalf("io.ReadAll(NewDecoder(...)): %v", err)
 	}
 
 	if !bytes.Equal(raw, decoded) {
@@ -428,14 +427,14 @@ LNEBUWIIDFON2CA3DBMJXXE5LNFY==
 	encodedShort := strings.ReplaceAll(encoded, "\n", "")
 
 	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
-	res1, err := ioutil.ReadAll(dec)
+	res1, err := io.ReadAll(dec)
 	if err != nil {
 		t.Errorf("ReadAll failed: %v", err)
 	}
 
 	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
 	var res2 []byte
-	res2, err = ioutil.ReadAll(dec)
+	res2, err = io.ReadAll(dec)
 	if err != nil {
 		t.Errorf("ReadAll failed: %v", err)
 	}
@@ -619,7 +618,7 @@ func TestBufferedDecodingSameError(t *testing.T) {
 			}()
 
 			decoder := NewDecoder(StdEncoding, pr)
-			_, err := ioutil.ReadAll(decoder)
+			_, err := io.ReadAll(decoder)
 
 			if err != testcase.expected {
 				t.Errorf("Expected %v, got %v; case %s %+v", testcase.expected, err, testcase.prefix, chunks)
@@ -718,7 +717,7 @@ func TestDecodeReadAll(t *testing.T) {
 				encoded = strings.ReplaceAll(encoded, "=", "")
 			}
 
-			decReader, err := ioutil.ReadAll(NewDecoder(encoding, strings.NewReader(encoded)))
+			decReader, err := io.ReadAll(NewDecoder(encoding, strings.NewReader(encoded)))
 			if err != nil {
 				t.Errorf("NewDecoder error: %v", err)
 			}
diff --git a/src/encoding/base64/base64_test.go b/src/encoding/base64/base64_test.go
index c2c9478a43..51047402bd 100644
--- a/src/encoding/base64/base64_test.go
+++ b/src/encoding/base64/base64_test.go
@@ -9,7 +9,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"reflect"
 	"runtime/debug"
 	"strings"
@@ -324,9 +323,9 @@ func TestBig(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Encoder.Close() = %v want nil", err)
 	}
-	decoded, err := ioutil.ReadAll(NewDecoder(StdEncoding, encoded))
+	decoded, err := io.ReadAll(NewDecoder(StdEncoding, encoded))
 	if err != nil {
-		t.Fatalf("ioutil.ReadAll(NewDecoder(...)): %v", err)
+		t.Fatalf("io.ReadAll(NewDecoder(...)): %v", err)
 	}
 
 	if !bytes.Equal(raw, decoded) {
@@ -403,7 +402,7 @@ func TestDecoderIssue3577(t *testing.T) {
 	})
 	errc := make(chan error, 1)
 	go func() {
-		_, err := ioutil.ReadAll(d)
+		_, err := io.ReadAll(d)
 		errc <- err
 	}()
 	select {
@@ -436,14 +435,14 @@ bqbPb06551Y4
 	encodedShort := strings.ReplaceAll(encoded, "\n", "")
 
 	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
-	res1, err := ioutil.ReadAll(dec)
+	res1, err := io.ReadAll(dec)
 	if err != nil {
 		t.Errorf("ReadAll failed: %v", err)
 	}
 
 	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
 	var res2 []byte
-	res2, err = ioutil.ReadAll(dec)
+	res2, err = io.ReadAll(dec)
 	if err != nil {
 		t.Errorf("ReadAll failed: %v", err)
 	}
@@ -517,14 +516,14 @@ func TestDecoderRaw(t *testing.T) {
 
 	// Through reader. Used to fail.
 	r := NewDecoder(RawURLEncoding, bytes.NewReader([]byte(source)))
-	dec2, err := ioutil.ReadAll(io.LimitReader(r, 100))
+	dec2, err := io.ReadAll(io.LimitReader(r, 100))
 	if err != nil || !bytes.Equal(dec2, want) {
 		t.Errorf("reading NewDecoder(RawURLEncoding, %q) = %x, %v, want %x, nil", source, dec2, err, want)
 	}
 
 	// Should work with padding.
 	r = NewDecoder(URLEncoding, bytes.NewReader([]byte(source+"==")))
-	dec3, err := ioutil.ReadAll(r)
+	dec3, err := io.ReadAll(r)
 	if err != nil || !bytes.Equal(dec3, want) {
 		t.Errorf("reading NewDecoder(URLEncoding, %q) = %x, %v, want %x, nil", source+"==", dec3, err, want)
 	}
diff --git a/src/encoding/binary/binary_test.go b/src/encoding/binary/binary_test.go
index 5971e0966a..83af89e8a7 100644
--- a/src/encoding/binary/binary_test.go
+++ b/src/encoding/binary/binary_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"reflect"
 	"strings"
@@ -524,7 +523,7 @@ func BenchmarkWriteStruct(b *testing.B) {
 	b.SetBytes(int64(Size(&s)))
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		Write(ioutil.Discard, BigEndian, &s)
+		Write(io.Discard, BigEndian, &s)
 	}
 }
 
diff --git a/src/encoding/gob/encoder_test.go b/src/encoding/gob/encoder_test.go
index 825f0d6f03..fe2774948a 100644
--- a/src/encoding/gob/encoder_test.go
+++ b/src/encoding/gob/encoder_test.go
@@ -8,7 +8,7 @@ import (
 	"bytes"
 	"encoding/hex"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"reflect"
 	"strings"
 	"testing"
@@ -938,7 +938,7 @@ func encodeAndRecover(value interface{}) (encodeErr, panicErr error) {
 		}
 	}()
 
-	encodeErr = NewEncoder(ioutil.Discard).Encode(value)
+	encodeErr = NewEncoder(io.Discard).Encode(value)
 	return
 }
 
diff --git a/src/encoding/hex/hex_test.go b/src/encoding/hex/hex_test.go
index 31e3f68936..7593e20db5 100644
--- a/src/encoding/hex/hex_test.go
+++ b/src/encoding/hex/hex_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"strings"
 	"testing"
 )
@@ -150,7 +149,7 @@ func TestEncoderDecoder(t *testing.T) {
 func TestDecoderErr(t *testing.T) {
 	for _, tt := range errTests {
 		dec := NewDecoder(strings.NewReader(tt.in))
-		out, err := ioutil.ReadAll(dec)
+		out, err := io.ReadAll(dec)
 		wantErr := tt.err
 		// Decoder is reading from stream, so it reports io.ErrUnexpectedEOF instead of ErrLength.
 		if wantErr == ErrLength {
diff --git a/src/encoding/json/bench_test.go b/src/encoding/json/bench_test.go
index 4a5fe7ec84..73c7b09fb6 100644
--- a/src/encoding/json/bench_test.go
+++ b/src/encoding/json/bench_test.go
@@ -15,7 +15,7 @@ import (
 	"compress/gzip"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
+	"io"
 	"os"
 	"reflect"
 	"runtime"
@@ -52,7 +52,7 @@ func codeInit() {
 	if err != nil {
 		panic(err)
 	}
-	data, err := ioutil.ReadAll(gz)
+	data, err := io.ReadAll(gz)
 	if err != nil {
 		panic(err)
 	}
@@ -89,7 +89,7 @@ func BenchmarkCodeEncoder(b *testing.B) {
 		b.StartTimer()
 	}
 	b.RunParallel(func(pb *testing.PB) {
-		enc := NewEncoder(ioutil.Discard)
+		enc := NewEncoder(io.Discard)
 		for pb.Next() {
 			if err := enc.Encode(&codeStruct); err != nil {
 				b.Fatal("Encode:", err)
@@ -399,7 +399,7 @@ func BenchmarkEncodeMarshaler(b *testing.B) {
 	}{}
 
 	b.RunParallel(func(pb *testing.PB) {
-		enc := NewEncoder(ioutil.Discard)
+		enc := NewEncoder(io.Discard)
 
 		for pb.Next() {
 			if err := enc.Encode(&m); err != nil {
diff --git a/src/encoding/json/stream_test.go b/src/encoding/json/stream_test.go
index c9e5334337..c284f2d965 100644
--- a/src/encoding/json/stream_test.go
+++ b/src/encoding/json/stream_test.go
@@ -7,7 +7,6 @@ package json
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
@@ -215,7 +214,7 @@ func TestDecoderBuffered(t *testing.T) {
 	if m.Name != "Gopher" {
 		t.Errorf("Name = %q; want Gopher", m.Name)
 	}
-	rest, err := ioutil.ReadAll(d.Buffered())
+	rest, err := io.ReadAll(d.Buffered())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -318,7 +317,7 @@ func BenchmarkEncoderEncode(b *testing.B) {
 	v := &T{"foo", "bar"}
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
-			if err := NewEncoder(ioutil.Discard).Encode(v); err != nil {
+			if err := NewEncoder(io.Discard).Encode(v); err != nil {
 				b.Fatal(err)
 			}
 		}
diff --git a/src/encoding/pem/pem_test.go b/src/encoding/pem/pem_test.go
index 8515b46498..b2b6b15e73 100644
--- a/src/encoding/pem/pem_test.go
+++ b/src/encoding/pem/pem_test.go
@@ -6,7 +6,7 @@ package pem
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"reflect"
 	"strings"
 	"testing"
@@ -271,7 +271,7 @@ func BenchmarkEncode(b *testing.B) {
 	data := &Block{Bytes: make([]byte, 65536)}
 	b.SetBytes(int64(len(data.Bytes)))
 	for i := 0; i < b.N; i++ {
-		Encode(ioutil.Discard, data)
+		Encode(io.Discard, data)
 	}
 }