decode: Have .scan() and .scanNumber() return *DecodeError

1 files changed, 30 insertions, 15 deletions

diff --git a/decode.go b/decode.go
index 522e41e..de10370 100644
--- a/decode.go
+++ b/decode.go
@@ -398,7 +398,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 	case val.CanAddr() && reflect.PointerTo(typ) == rawMessagePtrType:
 		t := dec.peekRuneType()
 		var buf bytes.Buffer
-		dec.scan(&buf)
+		if err := dec.scan(&buf); err != nil {
+			return err
+		}
 		if err := val.Addr().Interface().(*RawMessage).UnmarshalJSON(buf.Bytes()); err != nil {
 			return dec.newTypeError(t.JSONType(), reflect.PointerTo(typ), err)
 		}
@@ -417,7 +419,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 	case val.CanAddr() && reflect.PointerTo(typ).Implements(jsonUnmarshalerType):
 		t := dec.peekRuneType()
 		var buf bytes.Buffer
-		dec.scan(&buf)
+		if err := dec.scan(&buf); err != nil {
+			return err
+		}
 		obj := val.Addr().Interface().(jsonUnmarshaler)
 		if err := obj.UnmarshalJSON(buf.Bytes()); err != nil {
 			return dec.newTypeError(t.JSONType(), reflect.PointerTo(typ), err)
@@ -448,7 +452,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 				return dec.decodeNull()
 			}
 			var buf strings.Builder
-			dec.scanNumber(typ, &buf)
+			if err := dec.scanNumber(typ, &buf); err != nil {
+				return err
+			}
 			n, err := strconv.ParseInt(buf.String(), 10, kind2bits[kind])
 			if err != nil {
 				return dec.newTypeError("number "+buf.String(), typ, err)
@@ -459,7 +465,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 				return dec.decodeNull()
 			}
 			var buf strings.Builder
-			dec.scanNumber(typ, &buf)
+			if err := dec.scanNumber(typ, &buf); err != nil {
+				return err
+			}
 			n, err := strconv.ParseUint(buf.String(), 10, kind2bits[kind])
 			if err != nil {
 				return dec.newTypeError("number "+buf.String(), typ, err)
@@ -470,7 +478,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 				return dec.decodeNull()
 			}
 			var buf strings.Builder
-			dec.scanNumber(typ, &buf)
+			if err := dec.scanNumber(typ, &buf); err != nil {
+				return err
+			}
 			n, err := strconv.ParseFloat(buf.String(), kind2bits[kind])
 			if err != nil {
 				return dec.newTypeError("number "+buf.String(), typ, err)
@@ -483,7 +493,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			var buf strings.Builder
 			if typ == numberType {
 				t := dec.peekRuneType()
-				dec.scan(&buf)
+				if err := dec.scan(&buf); err != nil {
+					return err
+				}
 				if !t.IsNumber() {
 					return dec.newTypeError(t.JSONType(), typ,
 						fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number",
@@ -574,8 +586,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 					if dec.disallowUnknownFields {
 						return dec.newTypeError("", typ, fmt.Errorf("json: unknown field %q", name))
 					}
-					dec.scan(fastio.Discard)
-					return nil
+					return dec.scan(fastio.Discard)
 				}
 				field := index.ByPos[idx]
 				fVal := val
@@ -775,7 +786,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 					}
 					val.Index(i).Set(mValPtr.Elem())
 				} else {
-					dec.scan(fastio.Discard)
+					if err := dec.scan(fastio.Discard); err != nil {
+						return err
+					}
 				}
 				i++
 				return nil
@@ -805,7 +818,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 	return nil
 }
 
-func (dec *Decoder) scan(out fastio.RuneWriter) {
+func (dec *Decoder) scan(out fastio.RuneWriter) *DecodeError {
 	dec.io.PushReadBarrier()
 	for {
 		c, t := dec.readRune()
@@ -815,14 +828,14 @@ func (dec *Decoder) scan(out fastio.RuneWriter) {
 		_, _ = out.WriteRune(c)
 	}
 	dec.io.PopReadBarrier()
+	return nil
 }
 
-func (dec *Decoder) scanNumber(gTyp reflect.Type, out fastio.RuneWriter) {
+func (dec *Decoder) scanNumber(gTyp reflect.Type, out fastio.RuneWriter) *DecodeError {
 	if t := dec.peekRuneType(); !t.IsNumber() {
-		err := dec.newTypeError(t.JSONType(), gTyp, nil)
-		panic(decodeError(*err))
+		return dec.newTypeError(t.JSONType(), gTyp, nil)
 	}
-	dec.scan(out)
+	return dec.scan(out)
 }
 
 func (dec *Decoder) decodeAny() (any, *DecodeError) {
@@ -879,7 +892,9 @@ func (dec *Decoder) decodeAny() (any, *DecodeError) {
 		return buf.String(), nil
 	case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
 		var buf strings.Builder
-		dec.scan(&buf)
+		if err := dec.scan(&buf); err != nil {
+			return nil, err
+		}
 		num := Number(buf.String())
 		if dec.useNumber {
 			return num, nil