decode: Have .decodeNull() return a *DecodeError

1 files changed, 29 insertions, 25 deletions

diff --git a/decode.go b/decode.go
index 237c739..522e41e 100644
--- a/decode.go
+++ b/decode.go
@@ -424,8 +424,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 		}
 	case val.CanAddr() && reflect.PointerTo(typ).Implements(textUnmarshalerType):
 		if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-			dec.decodeNull()
-			return
+			return dec.decodeNull()
 		}
 		var buf bytes.Buffer
 		dec.decodeString(reflect.PointerTo(typ), &buf)
@@ -437,8 +436,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 		switch kind := typ.Kind(); kind {
 		case reflect.Bool:
 			if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-				dec.decodeNull()
-				return
+				return dec.decodeNull()
 			}
 			b, err := dec.decodeBool(typ)
 			if err != nil {
@@ -447,8 +445,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			val.SetBool(b)
 		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 			if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-				dec.decodeNull()
-				return
+				return dec.decodeNull()
 			}
 			var buf strings.Builder
 			dec.scanNumber(typ, &buf)
@@ -459,8 +456,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			val.SetInt(n)
 		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 			if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-				dec.decodeNull()
-				return
+				return dec.decodeNull()
 			}
 			var buf strings.Builder
 			dec.scanNumber(typ, &buf)
@@ -471,8 +467,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			val.SetUint(n)
 		case reflect.Float32, reflect.Float64:
 			if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-				dec.decodeNull()
-				return
+				return dec.decodeNull()
 			}
 			var buf strings.Builder
 			dec.scanNumber(typ, &buf)
@@ -483,8 +478,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			val.SetFloat(n)
 		case reflect.String:
 			if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-				dec.decodeNull()
-				return
+				return dec.decodeNull()
 			}
 			var buf strings.Builder
 			if typ == numberType {
@@ -537,7 +531,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			// Couldn't get type information from a pointer; fall back to untyped mode.
 			switch dec.peekRuneType() {
 			case jsonparse.RuneTypeNullN:
-				dec.decodeNull()
+				if err := dec.decodeNull(); err != nil {
+					return err
+				}
 				val.Set(reflect.Zero(typ))
 			default:
 				v, err := dec.decodeAny()
@@ -548,8 +544,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			}
 		case reflect.Struct:
 			if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-				dec.decodeNull()
-				return
+				return dec.decodeNull()
 			}
 			index := jsonstruct.IndexStruct(typ)
 			var nameBuf strings.Builder
@@ -603,7 +598,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 				if field.Quote {
 					switch t := dec.peekRuneType(); t {
 					case jsonparse.RuneTypeNullN:
-						dec.decodeNull()
+						if err := dec.decodeNull(); err != nil {
+							return err
+						}
 						switch fVal.Kind() {
 						// XXX: I can't justify this list, other than "it's what encoding/json
 						// does, but I don't understand their rationale".
@@ -636,7 +633,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 		case reflect.Map:
 			switch t := dec.peekRuneType(); t {
 			case jsonparse.RuneTypeNullN:
-				dec.decodeNull()
+				if err := dec.decodeNull(); err != nil {
+					return err
+				}
 				val.Set(reflect.Zero(typ))
 			case jsonparse.RuneTypeObjectBeg:
 				if val.IsNil() {
@@ -703,7 +702,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 				reflect.PointerTo(typ.Elem()).Implements(textUnmarshalerType))):
 				switch t := dec.peekRuneType(); t {
 				case jsonparse.RuneTypeNullN:
-					dec.decodeNull()
+					if err := dec.decodeNull(); err != nil {
+						return err
+					}
 					val.Set(reflect.Zero(typ))
 				case jsonparse.RuneTypeStringBeg:
 					if typ.Elem() == byteType {
@@ -727,7 +728,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			default:
 				switch t := dec.peekRuneType(); t {
 				case jsonparse.RuneTypeNullN:
-					dec.decodeNull()
+					if err := dec.decodeNull(); err != nil {
+						return err
+					}
 					val.Set(reflect.Zero(typ))
 				case jsonparse.RuneTypeArrayBeg:
 					if val.IsNil() {
@@ -756,8 +759,7 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 			}
 		case reflect.Array:
 			if nullOK && dec.peekRuneType() == jsonparse.RuneTypeNullN {
-				dec.decodeNull()
-				return
+				return dec.decodeNull()
 			}
 			i := 0
 			n := val.Len()
@@ -786,7 +788,9 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) (_err *DecodeError) {
 		case reflect.Pointer:
 			switch dec.peekRuneType() {
 			case jsonparse.RuneTypeNullN:
-				dec.decodeNull()
+				if err := dec.decodeNull(); err != nil {
+					return err
+				}
 				val.Set(reflect.Zero(typ))
 			default:
 				if val.IsNil() {
@@ -888,8 +892,7 @@ func (dec *Decoder) decodeAny() (any, *DecodeError) {
 	case 't', 'f':
 		return dec.decodeBool(nil)
 	case 'n':
-		dec.decodeNull()
-		return nil, nil
+		return nil, dec.decodeNull()
 	default:
 		panic("should not happen")
 	}
@@ -1169,9 +1172,10 @@ func (dec *Decoder) decodeBool(gTyp reflect.Type) (bool, *DecodeError) {
 	}
 }
 
-func (dec *Decoder) decodeNull() {
+func (dec *Decoder) decodeNull() *DecodeError {
 	dec.expectRune('n', jsonparse.RuneTypeNullN)
 	dec.expectRune('u', jsonparse.RuneTypeNullU)
 	dec.expectRune('l', jsonparse.RuneTypeNullL1)
 	dec.expectRune('l', jsonparse.RuneTypeNullL2)
+	return nil
 }