3 files changed, 46 insertions, 8 deletions

diff --git a/src/encoding/json/bench_test.go b/src/encoding/json/bench_test.go
index 047188131c..4e3bfe8bd2 100644
--- a/src/encoding/json/bench_test.go
+++ b/src/encoding/json/bench_test.go
@@ -14,6 +14,7 @@ package json
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"fmt"
 	"internal/testenv"
 	"internal/zstd"
@@ -581,3 +582,19 @@ func BenchmarkUnmarshalNumber(b *testing.B) {
 		}
 	}
 }
+
+func BenchmarkNewEncoderEncode(b *testing.B) {
+	m := make(map[string]string)
+	for i := range 100_000 {
+		k := fmt.Sprintf("key%d", i)
+		v := fmt.Sprintf("%x", sha256.Sum256([]byte(k)))
+		m[k] = v
+	}
+	b.ResetTimer()
+	b.ReportAllocs()
+	for b.Loop() {
+		if err := NewEncoder(io.Discard).Encode(m); err != nil {
+			b.Fatalf("Encode error: %v", err)
+		}
+	}
+}
diff --git a/src/encoding/json/v2_bench_test.go b/src/encoding/json/v2_bench_test.go
index b9ed7b6220..7057f9bec4 100644
--- a/src/encoding/json/v2_bench_test.go
+++ b/src/encoding/json/v2_bench_test.go
@@ -14,6 +14,8 @@ package json
 
 import (
 	"bytes"
+	"crypto/sha256"
+	"fmt"
 	"io"
 	"strings"
 	"testing"
@@ -481,3 +483,19 @@ func BenchmarkEncoderEncode(b *testing.B) {
 		}
 	})
 }
+
+func BenchmarkNewEncoderEncode(b *testing.B) {
+	m := make(map[string]string)
+	for i := range 100_000 {
+		k := fmt.Sprintf("key%d", i)
+		v := fmt.Sprintf("%x", sha256.Sum256([]byte(k)))
+		m[k] = v
+	}
+	b.ResetTimer()
+	b.ReportAllocs()
+	for b.Loop() {
+		if err := NewEncoder(io.Discard).Encode(m); err != nil {
+			b.Fatalf("Encode error: %v", err)
+		}
+	}
+}
diff --git a/src/encoding/json/v2_stream.go b/src/encoding/json/v2_stream.go
index ca0822cb73..ee16629cbb 100644
--- a/src/encoding/json/v2_stream.go
+++ b/src/encoding/json/v2_stream.go
@@ -96,7 +96,6 @@ type Encoder struct {
 	opts jsonv2.Options
 	err  error
 
-	buf       bytes.Buffer
 	indentBuf bytes.Buffer
 
 	indentPrefix string
@@ -121,21 +120,22 @@ func (enc *Encoder) Encode(v any) error {
 		return enc.err
 	}
 
-	buf := &enc.buf
-	buf.Reset()
-	if err := jsonv2.MarshalWrite(buf, v, enc.opts); err != nil {
+	e := export.GetBufferedEncoder(enc.opts)
+	defer export.PutBufferedEncoder(e)
+	if err := jsonv2.MarshalEncode(e, v); err != nil {
 		return err
 	}
+	b := export.Encoder(e).Buf // b must not leak current scope
 	if len(enc.indentPrefix)+len(enc.indentValue) > 0 {
 		enc.indentBuf.Reset()
-		if err := Indent(&enc.indentBuf, buf.Bytes(), enc.indentPrefix, enc.indentValue); err != nil {
+		if err := Indent(&enc.indentBuf, b, enc.indentPrefix, enc.indentValue); err != nil {
 			return err
 		}
-		buf = &enc.indentBuf
+		b = enc.indentBuf.Bytes()
 	}
-	buf.WriteByte('\n')
+	b = append(b, '\n')
 
-	if _, err := enc.w.Write(buf.Bytes()); err != nil {
+	if _, err := enc.w.Write(b); err != nil {
 		enc.err = err
 		return err
 	}
@@ -146,6 +146,9 @@ func (enc *Encoder) Encode(v any) error {
 // value as if indented by the package-level function Indent(dst, src, prefix, indent).
 // Calling SetIndent("", "") disables indentation.
 func (enc *Encoder) SetIndent(prefix, indent string) {
+	// NOTE: Do not rely on the newer [jsontext.WithIndent] option since
+	// the v1 [Indent] behavior has historical bugs that cannot be changed
+	// for backward compatibility reasons.
 	enc.indentPrefix = prefix
 	enc.indentValue = indent
 }