Return error if trying to marshal +Inf, -Inf or NaN

Author: dmitrybarsukov

jwriter/writer.go

@@ -2,7 +2,9 @@
 package jwriter
 
 import (
+	"fmt"
 	"io"
+	"math"
 	"strconv"
 	"unicode/utf8"
 
@@ -248,23 +250,39 @@ func (w *Writer) Int64Str(n int64) {
 }
 
 func (w *Writer) Float32(n float32) {
+	if w.checkIsUnsupportedFloat(float64(n)) {
+		return
+	}
+
 	w.Buffer.EnsureSpace(20)
 	w.Buffer.Buf = strconv.AppendFloat(w.Buffer.Buf, float64(n), 'g', -1, 32)
 }
 
 func (w *Writer) Float32Str(n float32) {
+	if w.checkIsUnsupportedFloat(float64(n)) {
+		return
+	}
+
 	w.Buffer.EnsureSpace(20)
 	w.Buffer.Buf = append(w.Buffer.Buf, '"')
 	w.Buffer.Buf = strconv.AppendFloat(w.Buffer.Buf, float64(n), 'g', -1, 32)
 	w.Buffer.Buf = append(w.Buffer.Buf, '"')
 }
 
 func (w *Writer) Float64(n float64) {
+	if w.checkIsUnsupportedFloat(n) {
+		return
+	}
+
 	w.Buffer.EnsureSpace(20)
 	w.Buffer.Buf = strconv.AppendFloat(w.Buffer.Buf, n, 'g', -1, 64)
 }
 
 func (w *Writer) Float64Str(n float64) {
+	if w.checkIsUnsupportedFloat(n) {
+		return
+	}
+
 	w.Buffer.EnsureSpace(20)
 	w.Buffer.Buf = append(w.Buffer.Buf, '"')
 	w.Buffer.Buf = strconv.AppendFloat(w.Buffer.Buf, float64(n), 'g', -1, 64)
@@ -415,3 +433,16 @@ func (w *Writer) base64(in []byte) {
 		w.Buffer.Buf = append(w.Buffer.Buf, byte(padChar), byte(padChar))
 	}
 }
+
+func (w *Writer) checkIsUnsupportedFloat(val float64) bool {
+	isUnsupported := math.IsNaN(val) || math.IsInf(val, 0)
+	if isUnsupported && w.Error == nil {
+		w.Error = newUnsupportedValueError(val)
+	}
+
+	return isUnsupported
+}
+
+func newUnsupportedValueError(value any) error {
+	return fmt.Errorf("json: unsupported value: %v", value)
+}

tests/errors.go

@@ -24,3 +24,9 @@ type ErrorNestedStruct struct {
 
 //easyjson:json
 type ErrorIntMap map[uint32]string
+
+//easyjson:json
+type ErrorFloatTypes struct {
+	Float64 float64 `json:"float64"`
+	Float32 float32 `json:"float32"`
+}

tests/errors_test.go

@@ -1,6 +1,7 @@
 package tests
 
 import (
+	"math"
 	"testing"
 
 	"github.com/mailru/easyjson/jlexer"
@@ -283,3 +284,40 @@ func TestMultipleErrorsIntMap(t *testing.T) {
 		}
 	}
 }
+
+func TestUnsupportedFloatValues(t *testing.T) {
+	for i, test := range []struct {
+		Value       ErrorFloatTypes
+		ExpectedErr string
+	}{
+		{
+			Value:       ErrorFloatTypes{Float64: math.NaN()},
+			ExpectedErr: "json: unsupported value: NaN",
+		},
+		{
+			Value:       ErrorFloatTypes{Float64: math.Inf(1)},
+			ExpectedErr: "json: unsupported value: +Inf",
+		},
+		{
+			Value:       ErrorFloatTypes{Float64: math.Inf(-1)},
+			ExpectedErr: "json: unsupported value: -Inf",
+		},
+		{
+			Value:       ErrorFloatTypes{Float32: float32(math.NaN())},
+			ExpectedErr: "json: unsupported value: NaN",
+		},
+		{
+			Value:       ErrorFloatTypes{Float32: float32(math.Inf(1))},
+			ExpectedErr: "json: unsupported value: +Inf",
+		},
+		{
+			Value:       ErrorFloatTypes{Float32: float32(math.Inf(-1))},
+			ExpectedErr: "json: unsupported value: -Inf",
+		},
+	} {
+		_, err := test.Value.MarshalJSON()
+		if err == nil || err.Error() != test.ExpectedErr {
+			t.Errorf("[%d] TestUnsupportedFloatValues(): error: want %s, got %v", i, test.ExpectedErr, err)
+		}
+	}
+}