[PyROOT] cppyy.ll.cast() does not understand the type of a branch (invocation through GetBranchAttr)

[Nowakus]

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Description

The new cppyy produces an error when we try to call GetBranchAttr on one of our DataVector branches.

Reproducer

Reproducer using only the ATLAS environment, no files necessary:

export ATLAS_LOCAL_ROOT_BASE=/cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase 
source $ATLAS_LOCAL_ROOT_BASE/user/atlasLocalSetup.sh
asetup main--dev4LCG,latest,Athena
python

    import ROOT, cppyy.ll
    ROOT.TClass.GetClass('DataVector<xAOD::PixelCluster_v1>').HasDictionary()

True

    cppyy.ll.cast['DataVector<xAOD::PixelCluster_v1>'](0)

TypeError: Could not find "cppyy_cast<DataVector<xAOD::PixelCluster_v1>>" (set cppyy.set_debug() for C++ errors):
  Failed to instantiate "cppyy_cast<DataVector<xAOD::PixelCluster_v1>>(int)"

but using a typedef to the DataVector works (note the real type of the returned object):

    cppyy.ll.cast['xAOD::PixelClusterContainer_v1>'](0)

<cppyy.gbl.DataVector<xAOD::PixelCluster_v1> object at 0x11cbd2c0>

and after the previous call autoloaded some libraries, the real type starts to work as well:

    cppyy.ll.cast['DataVector<xAOD::PixelCluster_v1>'](0)

<cppyy.gbl.DataVector<xAOD::PixelCluster_v1> object at 0x1f542770>

ROOT version

6.32+, possibly since 6.30

Installation method

SFT dev nightlies

Operating system

alma9

Additional context

No response

[amete]

Hi @guitargeek, has there been any progress on this? Many thanks.