Missing numpy.uint8 pythonisation in SetBranchAddress in ROOT 6.38

[dpiparo]

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Description

(from this post on the Forum)

In my code I had the following part:

self.pcd = np.zeros((X, Y, A, B), dtype=np.uint8)
self.tree_chain.SetBranchAddress("photon_count_data", self.pcd)

where photon_count_data is photon_count_data[1][1][48][48]/b

It used to work in older ROOT versions (6.30 I think), but now I get an error:

  File "/home/lewhoo/workspace/etos/eusottrees/datatree.py", line 1652, in set_physical_tree
    self.tree_chain.SetBranchAddress("photon_count_data", self.pcd)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/lewhoo/software/root/root-6.38.00/lib/ROOT/_pythonization/_ttree.py", line 266, in _SetBranchAddress
    data_type = _determine_data_type(addr)
  File "/home/lewhoo/software/root/root-6.38.00/lib/ROOT/_pythonization/_ttree.py", line 233, in _determine_data_type
    return _get_cpp_type_from_numpy_type(addr.__array_interface__["typestr"][1:])
  File "/home/lewhoo/software/root/root-6.38.00/lib/ROOT/_pythonization/_rvec.py", line 149, in _get_cpp_type_from_numpy_type
    raise RuntimeError("Object not convertible: Python object has unknown data-type '" + dtype + "'.")
RuntimeError: Object not convertible: Python object has unknown data-type 'u1'.

The workaround (suggested by Gemini 😉 ) is to use GetBranch(“…”).SetAddress(…) and this works. However, it seems that proper conversion from numpy array uint8 to C++ unsigned char is missing.

Reproducer

See above

ROOT version

6.38 onwards

Installation method

all

Operating system

all

Additional context

No response