Need for the data object to be in TES to create links
For the packers/unpackers, it's required to put the data object in TES before one can add links to it. This requirement makes all packers/unpackers to use Read/WriteDataHandles and put packed objects in TES even if they are not persisted later.
To test this: Checkout Moore/sevda-packers2 LHCb/sevda-packers2
In Moore/Hlt/Moore/python/Moore/persistence/packing.py Set enable_check to True for packers
In LHCb/Event/EventPacker/src/component/BufferPackerBaseAlg.h Comment out line 57,60,64,65,66
Compile and rerun the test.
@sponce might know more.