fix(dynamodb): fix StringSet, NumberSet and BinarySet decoding

feature/dynamodb/attributevalue/decode.go

@@ -243,6 +243,10 @@ type DecoderOptions struct {
 	// call UnmarshalText on the target. If the attributevalue is a binary, its
 	// value will be used to call UnmarshalBinary.
 	UseEncodingUnmarshalers bool
+
+	// When enabled, the decoder will call Unmarshaler.UnmarshalDynamoDBAttributeValue
+	// for each individual set item instead of the whole set at once.
+	UnmarshalIndividualSetValues bool
 }
 
 // A Decoder provides unmarshaling AttributeValues to Go value types.
@@ -447,7 +451,15 @@ func (d *Decoder) decodeBinarySet(bs [][]byte, v reflect.Value) error {
 		}
 		u, elem := indirect[Unmarshaler](v.Index(i), indirectOptions{})
 		if u != nil {
-			return u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberBS{Value: bs})
+			if d.options.UnmarshalIndividualSetValues {
+				err := u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberB{Value: bs[i]})
+				if err != nil {
+					return err
+				}
+				continue
+			} else {
+				return u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberBS{Value: bs})
+			}
 		}
 		if err := d.decodeBinary(bs[i], elem); err != nil {
 			return err
@@ -582,7 +594,15 @@ func (d *Decoder) decodeNumberSet(ns []string, v reflect.Value) error {
 		}
 		u, elem := indirect[Unmarshaler](v.Index(i), indirectOptions{})
 		if u != nil {
-			return u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberNS{Value: ns})
+			if d.options.UnmarshalIndividualSetValues {
+				err := u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberN{Value: ns[i]})
+				if err != nil {
+					return err
+				}
+				continue
+			} else {
+				return u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberNS{Value: ns})
+			}
 		}
 		if err := d.decodeNumber(ns[i], elem, tag{}); err != nil {
 			return err
@@ -804,7 +824,15 @@ func (d *Decoder) decodeStringSet(ss []string, v reflect.Value) error {
 		}
 		u, elem := indirect[Unmarshaler](v.Index(i), indirectOptions{})
 		if u != nil {
-			return u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberSS{Value: ss})
+			if d.options.UnmarshalIndividualSetValues {
+				err := u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberS{Value: ss[i]})
+				if err != nil {
+					return err
+				}
+				continue
+			} else {
+				return u.UnmarshalDynamoDBAttributeValue(&types.AttributeValueMemberSS{Value: ss})
+			}
 		}
 		if err := d.decodeString(ss[i], elem, tag{}); err != nil {
 			return err

feature/dynamodb/attributevalue/decode_test.go

@@ -1268,3 +1268,79 @@ func TestUnmarshalBinary(t *testing.T) {
 		t.Errorf("expected %v, got %v", expected, actual)
 	}
 }
+
+type testStringItem string
+
+func (t *testStringItem) UnmarshalDynamoDBAttributeValue(av types.AttributeValue) error {
+	v, ok := av.(*types.AttributeValueMemberS)
+	if !ok {
+		return fmt.Errorf("expecting string value")
+	}
+	*t = testStringItem(v.Value)
+	return nil
+}
+
+type testNumberItem float64
+
+func (t *testNumberItem) UnmarshalDynamoDBAttributeValue(av types.AttributeValue) error {
+	v, ok := av.(*types.AttributeValueMemberN)
+	if !ok {
+		return fmt.Errorf("expecting number value")
+	}
+	n, err := strconv.ParseFloat(v.Value, 64)
+	if err != nil {
+		return err
+	}
+	*t = testNumberItem(n)
+	return nil
+}
+
+type testBinaryItem []byte
+
+func (t *testBinaryItem) UnmarshalDynamoDBAttributeValue(av types.AttributeValue) error {
+	v, ok := av.(*types.AttributeValueMemberB)
+	if !ok {
+		return fmt.Errorf("expecting binary value")
+	}
+	*t = make([]byte, len(v.Value))
+	copy(*t, v.Value)
+	return nil
+}
+
+type testStringSetWithUnmarshaler struct {
+	Strings  []testStringItem `dynamodbav:",stringset"`
+	Numbers  []testNumberItem `dynamodbav:",numberset"`
+	Binaries []testBinaryItem `dynamodbav:",binaryset"`
+}
+
+func TestUnmarshalIndividualSetValues(t *testing.T) {
+	in := &types.AttributeValueMemberM{
+		Value: map[string]types.AttributeValue{
+			"Strings": &types.AttributeValueMemberSS{
+				Value: []string{"a", "b"},
+			},
+			"Numbers": &types.AttributeValueMemberNS{
+				Value: []string{"1", "2"},
+			},
+			"Binaries": &types.AttributeValueMemberBS{
+				Value: [][]byte{{1, 2}, {3, 4}},
+			},
+		},
+	}
+	var actual testStringSetWithUnmarshaler
+	err := UnmarshalWithOptions(in, &actual, func(o *DecoderOptions) {
+		o.UnmarshalIndividualSetValues = true
+	})
+	if err != nil {
+		t.Fatalf("expect no error, got %v", err)
+	}
+
+	expected := testStringSetWithUnmarshaler{
+		Strings:  []testStringItem{"a", "b"},
+		Numbers:  []testNumberItem{1, 2},
+		Binaries: []testBinaryItem{{1, 2}, {3, 4}},
+	}
+	if diff := cmpDiff(expected, actual); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+}

feature/dynamodbstreams/attributevalue/decode.go

@@ -243,6 +243,10 @@ type DecoderOptions struct {
 	// call UnmarshalText on the target. If the attributevalue is a binary, its
 	// value will be used to call UnmarshalBinary.
 	UseEncodingUnmarshalers bool
+
+	// When enabled, the decoder will call Unmarshaler.UnmarshalDynamoDBStreamsAttributeValue
+	// for each individual set item instead of the whole set at once.
+	UnmarshalIndividualSetValues bool
 }
 
 // A Decoder provides unmarshaling AttributeValues to Go value types.
@@ -447,7 +451,15 @@ func (d *Decoder) decodeBinarySet(bs [][]byte, v reflect.Value) error {
 		}
 		u, elem := indirect[Unmarshaler](v.Index(i), indirectOptions{})
 		if u != nil {
-			return u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberBS{Value: bs})
+			if d.options.UnmarshalIndividualSetValues {
+				err := u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberB{Value: bs[i]})
+				if err != nil {
+					return err
+				}
+				continue
+			} else {
+				return u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberBS{Value: bs})
+			}
 		}
 		if err := d.decodeBinary(bs[i], elem); err != nil {
 			return err
@@ -582,7 +594,15 @@ func (d *Decoder) decodeNumberSet(ns []string, v reflect.Value) error {
 		}
 		u, elem := indirect[Unmarshaler](v.Index(i), indirectOptions{})
 		if u != nil {
-			return u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberNS{Value: ns})
+			if d.options.UnmarshalIndividualSetValues {
+				err := u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberN{Value: ns[i]})
+				if err != nil {
+					return err
+				}
+				continue
+			} else {
+				return u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberNS{Value: ns})
+			}
 		}
 		if err := d.decodeNumber(ns[i], elem, tag{}); err != nil {
 			return err
@@ -804,7 +824,15 @@ func (d *Decoder) decodeStringSet(ss []string, v reflect.Value) error {
 		}
 		u, elem := indirect[Unmarshaler](v.Index(i), indirectOptions{})
 		if u != nil {
-			return u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberSS{Value: ss})
+			if d.options.UnmarshalIndividualSetValues {
+				err := u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberS{Value: ss[i]})
+				if err != nil {
+					return err
+				}
+				continue
+			} else {
+				return u.UnmarshalDynamoDBStreamsAttributeValue(&types.AttributeValueMemberSS{Value: ss})
+			}
 		}
 		if err := d.decodeString(ss[i], elem, tag{}); err != nil {
 			return err

feature/dynamodbstreams/attributevalue/decode_test.go

@@ -1268,3 +1268,79 @@ func TestUnmarshalBinary(t *testing.T) {
 		t.Errorf("expected %v, got %v", expected, actual)
 	}
 }
+
+type testStringItem string
+
+func (t *testStringItem) UnmarshalDynamoDBStreasmAttributeValue(av types.AttributeValue) error {
+	v, ok := av.(*types.AttributeValueMemberS)
+	if !ok {
+		return fmt.Errorf("expecting string value")
+	}
+	*t = testStringItem(v.Value)
+	return nil
+}
+
+type testNumberItem float64
+
+func (t *testNumberItem) UnmarshalDynamoDBStreamsAttributeValue(av types.AttributeValue) error {
+	v, ok := av.(*types.AttributeValueMemberN)
+	if !ok {
+		return fmt.Errorf("expecting number value")
+	}
+	n, err := strconv.ParseFloat(v.Value, 64)
+	if err != nil {
+		return err
+	}
+	*t = testNumberItem(n)
+	return nil
+}
+
+type testBinaryItem []byte
+
+func (t *testBinaryItem) UnmarshalDynamoDBStreamsAttributeValue(av types.AttributeValue) error {
+	v, ok := av.(*types.AttributeValueMemberB)
+	if !ok {
+		return fmt.Errorf("expecting binary value")
+	}
+	*t = make([]byte, len(v.Value))
+	copy(*t, v.Value)
+	return nil
+}
+
+type testStringSetWithUnmarshaler struct {
+	Strings  []testStringItem `dynamodbav:",stringset"`
+	Numbers  []testNumberItem `dynamodbav:",numberset"`
+	Binaries []testBinaryItem `dynamodbav:",binaryset"`
+}
+
+func TestUnmarshalIndividualSetValues(t *testing.T) {
+	in := &types.AttributeValueMemberM{
+		Value: map[string]types.AttributeValue{
+			"Strings": &types.AttributeValueMemberSS{
+				Value: []string{"a", "b"},
+			},
+			"Numbers": &types.AttributeValueMemberNS{
+				Value: []string{"1", "2"},
+			},
+			"Binaries": &types.AttributeValueMemberBS{
+				Value: [][]byte{{1, 2}, {3, 4}},
+			},
+		},
+	}
+	var actual testStringSetWithUnmarshaler
+	err := UnmarshalWithOptions(in, &actual, func(o *DecoderOptions) {
+		o.UnmarshalIndividualSetValues = true
+	})
+	if err != nil {
+		t.Fatalf("expect no error, got %v", err)
+	}
+
+	expected := testStringSetWithUnmarshaler{
+		Strings:  []testStringItem{"a", "b"},
+		Numbers:  []testNumberItem{1, 2},
+		Binaries: []testBinaryItem{{1, 2}, {3, 4}},
+	}
+	if diff := cmpDiff(expected, actual); diff != "" {
+		t.Errorf("expect value match\n%s", diff)
+	}
+}