service/dynamodb/dynamodbattribute: Support string type alias for map…

… keys

CHANGELOG_PENDING.md

@@ -9,3 +9,4 @@
   * Fixes incorrect modifications to the previous token value of the skipper. Adds checks for cases where a skipped statement should be marked as complete and not be ignored.
   * Adds tests for nested and empty field value parsing, along with tests suggested in [#2801](https://github.com/aws/aws-sdk-go/pull/2801)
   * Fixes [#2800](https://github.com/aws/aws-sdk-go/issues/2800)
+* `service/dynamodb/dynamodbattribute`: Fixes a panic when decoding into a map with a key string type alias. ([#2870](https://github.com/aws/aws-sdk-go/pull/2870))

service/dynamodb/dynamodbattribute/decode.go

@@ -489,7 +489,8 @@ func (d *Decoder) decodeMap(avMap map[string]*dynamodb.AttributeValue, v reflect
 
 	if v.Kind() == reflect.Map {
 		for k, av := range avMap {
-			key := reflect.ValueOf(k)
+			key := reflect.New(v.Type().Key()).Elem()
+			key.SetString(k)
 			elem := reflect.New(v.Type().Elem()).Elem()
 			if err := d.decode(av, elem, tag{}); err != nil {
 				return err

service/dynamodb/dynamodbattribute/shared_test.go

@@ -58,6 +58,8 @@ type testAliasedStruct struct {
 
 	Value13 testAliasedBool
 	Value14 testAliasedBoolSlice
+
+	Value15 map[testAliasedString]string
 }
 
 type testNamedPointer *int
@@ -256,6 +258,9 @@ var sharedTestCases = []struct {
 					{BOOL: aws.Bool(false)},
 					{BOOL: aws.Bool(true)},
 				}},
+				"Value15": {M: map[string]*dynamodb.AttributeValue{
+					"TestKey": {S: aws.String("TestElement")},
+				}},
 			},
 		},
 		actual: &testAliasedStruct{},
@@ -278,6 +283,9 @@ var sharedTestCases = []struct {
 			Value12: testAliasedStringSlice{"1", "2", "3"},
 			Value13: true,
 			Value14: testAliasedBoolSlice{true, false, true},
+			Value15: map[testAliasedString]string{
+				"TestKey": "TestElement",
+			},
 		},
 	},
 	{