geant4 : Transfer of material properties does not appear to work.

[stewartboogert]

Transfer of material properties does not appear to work. Quick fix, but might not be general

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 74.12%. Comparing base (cf097c1) to head (735a8ee).

Files with missing lines	Patch %	Lines
src/pyg4ometry/geant4/Registry.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #127      +/-   ##
==========================================
- Coverage   74.12%   74.12%   -0.01%     
==========================================
  Files         157      157              
  Lines       22735    22736       +1     
==========================================
  Hits        16853    16853              
- Misses       5882     5883       +1     

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[lnevay]

So a similar line of code is on line 170 just above. If the one you propose should be changed, then so should this...

[lnevay]

More generally, we have two functions "transferDefine" and "transferDefines". We've written that the second should do it recursively. So the second works on Defines.VectorBase, Defines.ScalarBase and Defines.Matrix.

Looking through pyg4ometry/gdml/Defines.py this should cover everything... APART from the Auxiliary class.

Therefore, I would say that what should actually happen is not this change but we add something to "transferDefines" that handles the pyg4ometry.gdml.Defines.Auxiliary class.

Conceptually, "transferDefines" should handle any define type.

[lnevay]

See comments.

[stewartboogert]

As suspected I didn't really understand the subtle aspects of this. The problem I encountered was with the transfer of optical properties, not Auxiliary. This PR fixed that problem, but likely not to be correct. I'll make an issue showing the problem and maybe you can implement the general fix.

Let's leave this PR open for reference.