fix: issue where Decoder panics when decoding an Object containing a …

…Map with int8/int16 as key or value type

map.go

@@ -219,7 +219,16 @@ func (d *Decoder) decMapByValue(value reflect.Value) error {
 			return perrors.WithStack(err)
 		}
 
-		m.Elem().SetMapIndex(EnsurePackValue(entryKey), EnsureRawValue(entryValue))
+		// add a layer of conversion to make the map compatible with more types during decoding
+		key := EnsurePackValue(entryKey)
+		if mKey := m.Elem().Type().Key(); key.Type().ConvertibleTo(mKey) {
+			key = key.Convert(mKey)
+		}
+		val := EnsureRawValue(entryValue)
+		if mVal := m.Elem().Type().Elem(); val.Type().ConvertibleTo(mVal) {
+			val = val.Convert(mVal)
+		}
+		m.Elem().SetMapIndex(key, val)
 	}
 
 	SetValue(value, m)

map_test.go

@@ -182,3 +182,42 @@ func TestJavaMap(t *testing.T) {
 	RegisterPOJO(customMap)
 	testJavaDecode(t, "customArgTypedFixed_CustomMap", customMap)
 }
+
+type Obj struct {
+	Map8  map[int8]int8
+	Map16 map[int16]int16
+	Map32 map[int32]int32
+}
+
+func (Obj) JavaClassName() string {
+	return ""
+}
+
+func TestMapInObject(t *testing.T) {
+	var (
+		obj Obj
+		e   *Encoder
+		d   *Decoder
+		err error
+		res interface{}
+	)
+
+	obj = Obj{
+		Map8:  map[int8]int8{1: 2, 3: 4},
+		Map16: map[int16]int16{1: 2, 3: 4},
+		Map32: map[int32]int32{1: 2, 3: 4},
+	}
+
+	e = NewEncoder()
+	e.Encode(obj)
+	if len(e.Buffer()) == 0 {
+		t.Fail()
+	}
+
+	d = NewDecoder(e.Buffer())
+	res, err = d.Decode()
+	if err != nil {
+		t.Errorf("Decode() = %+v", err)
+	}
+	t.Logf("decode(%v) = %v, %v\n", obj, res, err)
+}