Add tests for the actual usability of the Decodable and Encodable interfaces

1 files changed, 26 insertions, 8 deletions

diff --git a/decode.go b/decode.go
index c160192..fbf2373 100644
--- a/decode.go
+++ b/decode.go
@@ -300,9 +300,13 @@ func (dec *Decoder) decode(val reflect.Value, nullOK bool) {
 	case val.CanAddr() && reflect.PointerTo(typ).Implements(decodableType):
 		t := dec.peekRuneType()
 		obj := val.Addr().Interface().(Decodable)
-		if err := obj.DecodeJSON(dec.limitingScanner()); err != nil {
+		l := dec.limitingScanner()
+		if err := obj.DecodeJSON(l); err != nil {
 			dec.panicType(t.jsonType(), typ, err)
 		}
+		if _, _, err := l.ReadRune(); err != io.EOF {
+			dec.panicType(t.jsonType(), typ, fmt.Errorf("did not consume entire %s", t.jsonType()))
+		}
 	case val.CanAddr() && reflect.PointerTo(typ).Implements(jsonUnmarshalerType):
 		t := dec.peekRuneType()
 		var buf bytes.Buffer
@@ -724,7 +728,7 @@ func (dec *Decoder) decodeAny() any {
 }
 
 // DecodeObject is a helper function for implementing the Decoder interface.
-func DecodeObject(r io.RuneScanner, decodeKey, decodeVal func() error) (err error) {
+func DecodeObject(r io.RuneScanner, decodeKey, decodeVal func(io.RuneScanner) error) (err error) {
 	defer func() {
 		if r := recover(); r != nil {
 			if de, ok := r.(decodeError); ok {
@@ -738,13 +742,22 @@ func DecodeObject(r io.RuneScanner, decodeKey, decodeVal func() error) (err erro
 	dec := NewDecoder(r)
 	dec.decodeObject(nil,
 		func() {
-			if err := decodeKey(); err != nil {
+			l := dec.limitingScanner()
+			if err := decodeKey(l); err != nil {
 				dec.panicType("string", nil, err)
 			}
+			if _, _, err := l.ReadRune(); err != io.EOF {
+				dec.panicType("string", nil, fmt.Errorf("did not consume entire string"))
+			}
 		},
 		func() {
-			if err := decodeVal(); err != nil {
-				dec.panicType("", nil, err)
+			t := dec.peekRuneType()
+			l := dec.limitingScanner()
+			if err := decodeVal(l); err != nil {
+				dec.panicType(t.jsonType(), nil, err)
+			}
+			if _, _, err := l.ReadRune(); err != io.EOF {
+				dec.panicType(t.jsonType(), nil, fmt.Errorf("did not consume entire %s", t.jsonType()))
 			}
 		})
 	return
@@ -778,7 +791,7 @@ func (dec *Decoder) decodeObject(gTyp reflect.Type, decodeKey, decodeVal func())
 }
 
 // DecodeArray is a helper function for implementing the Decoder interface.
-func DecodeArray(r io.RuneScanner, decodeMember func() error) (err error) {
+func DecodeArray(r io.RuneScanner, decodeMember func(r io.RuneScanner) error) (err error) {
 	defer func() {
 		if r := recover(); r != nil {
 			if de, ok := r.(decodeError); ok {
@@ -791,8 +804,13 @@ func DecodeArray(r io.RuneScanner, decodeMember func() error) (err error) {
 	}()
 	dec := NewDecoder(r)
 	dec.decodeArray(nil, func() {
-		if err := decodeMember(); err != nil {
-			dec.panicType("array", nil, err)
+		t := dec.peekRuneType()
+		l := dec.limitingScanner()
+		if err := decodeMember(l); err != nil {
+			dec.panicType(t.jsonType(), nil, err)
+		}
+		if _, _, err := l.ReadRune(); err != io.EOF {
+			dec.panicType(t.jsonType(), nil, fmt.Errorf("did not consume entire %s", t.jsonType()))
 		}
 	})
 	return