service/s3/s3manager: Fix check for nil OrigErr in Error()(aws#1749)

S3 Manager's `Error` type did not check for nil of `OrigErr` when calling `Error()`

Fix aws#1748

service/s3/s3manager/batch.go

@@ -60,7 +60,15 @@ func newError(err error, bucket, key *string) Error {
 }
 
 func (err *Error) Error() string {
-	return fmt.Sprintf("failed to upload %q to %q:\n%s", err.Key, err.Bucket, err.OrigErr.Error())
+	origErr := ""
+	if err.OrigErr != nil {
+		origErr = ":\n" + err.OrigErr.Error()
+	}
+	return fmt.Sprintf("failed to upload %q to %q%s",
+		aws.StringValue(err.Key),
+		aws.StringValue(err.Bucket),
+		origErr,
+	)
 }
 
 // NewBatchError will return a BatchError that satisfies the awserr.Error interface.

service/s3/s3manager/batch_test.go

@@ -321,6 +321,30 @@ func (client *mockS3Client) ListObjects(input *s3.ListObjectsInput) (*s3.ListObj
 	return object, nil
 }
 
+func TestNilOrigError(t *testing.T) {
+	err := Error{
+		Bucket: aws.String("bucket"),
+		Key:    aws.String("key"),
+	}
+	errStr := err.Error()
+	const expected1 = `failed to upload "key" to "bucket"`
+	if errStr != expected1 {
+		t.Errorf("Expected %s, but received %s", expected1, errStr)
+	}
+
+	err = Error{
+		OrigErr: errors.New("foo"),
+		Bucket: aws.String("bucket"),
+		Key:    aws.String("key"),
+	}
+	errStr = err.Error()
+	const expected2 = "failed to upload \"key\" to \"bucket\":\nfoo"
+	if errStr != expected2 {
+		t.Errorf("Expected %s, but received %s", expected2, errStr)
+	}
+
+}
+
 func TestBatchDeleteList(t *testing.T) {
 	count := 0