use lazy initialization to resolve circular dependency between the DataFieldSerializer, DataTypeSerializer, and RowTypeSerializer classes that causes NPE for certain RowTypes like nested row type

[umeshdangat]

There is a circular dependency between the DataFieldSerializer, DataTypeSerializer, and RowTypeSerializer classes. This circular dependency can lead to incomplete initialization of the serializers, causing a NullPointerException when you attempt to use them.

Here's a breakdown of the problem:

1. DataFieldSerializer has a DataTypeSerializer instance.
2. DataTypeSerializer has a RowTypeSerializer instance.
3. RowTypeSerializer has a ListSerializer<DataField> instance, which in turn uses DataFieldSerializer.

This circular dependency can cause the serializers to be in an incomplete state when they are first accessed, leading to the NullPointerException.

Code below is enough to re-create this NPE

        RowType innerMostRowType = RowType.of(DataTypes.BIGINT());
        RowType outerRowType = RowType.of(
                DataTypes.ROW(DataTypes.FIELD("outerRow", innerMostRowType)));

        DataTypeSerializer serializer = new DataTypeSerializer();


        assertNotNull(RowTypeSerializer.INSTANCE, "RowTypeSerializer.INSTANCE is null");
        RowType copiedRow = (RowType) serializer.copy(outerRowType);

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity for 60 days. It will be closed in 30 days if no further activity occurs.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity for 60 days. It will be closed in 30 days if no further activity occurs.

[github-actions]

This pull request has been closed because it has not had recent activity. You could reopen it if you try to continue your work, and anyone who are interested in it are encouraged to continue work on this pull request.

[yuxiqian]

Could @leonardBang please reopen this?

[umeshdangat]

PR #3434 also has this change! Merging that should enable us to close this.