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https://issues.apache.org/jira/browse/FLINK-16724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17064753#comment-17064753
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Chongchen Chen commented on FLINK-16724:
----------------------------------------
making history data deserialized correctly is a hard problem. I have a
solution, but it's tricky. Maybe we should have a better solution.
{code:java}
// code placeholder
public void serialize(List<T> list, DataOutputView target) throws IOException {
final int size = list.size();
target.writeInt(-size); // use negative num to represent new serialization
schema. in deserialize method, if non-negative value is found, use old schema,
otherwise use new schema.
// We iterate here rather than accessing by index, because we cannot be sure
that
// the given list supports RandomAccess.
// The Iterator should be stack allocated on new JVMs (due to escape
analysis)
for (T element : list) {
boolean isNull = element == null;
target.writeBoolean(isNull);
if (!isNull) {
elementSerializer.serialize(element, target);
}
}
}{code}
> ListSerializer cannot serialize list which containers null
> ----------------------------------------------------------
>
> Key: FLINK-16724
> URL: https://issues.apache.org/jira/browse/FLINK-16724
> Project: Flink
> Issue Type: Bug
> Reporter: Chongchen Chen
> Priority: Major
> Attachments: list_serializer_err.diff
>
>
> MapSerializer handles null value correctly, but ListSerializer doesn't. The
> attachment is the modification of unit test that can reproduce the bug.
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