Comment 4 for bug 2051256

Hi Andy,

Yes indeed when that code was implemented we had to workaround an hepmc bug of the time.
And stephan was forcing to use a dedicated version of hepmc (that we likely still need/ship) in order for this to work.

Concerning the scomp/... flag, I have simply remove their inclusion within the hepmc file. Since I'm not aware of anyone using those information for computing merging scale uncertainty from post-processing the hepmc file. In any case for the people doing it (if any), this is as problematic as changing the name of those weights. So let's wait that someone complain here.

For hepmc3, if you want us to support it, the best is likely to do it within the cern school when we can sit together with a pythia8 author and see what needs to be done, in principle this is likely a pure change of configuration within pythia8 and, maybe, a bunch of check to adapt (the one checking that py8 produces the correct output file). But yes that file might be the complex part to handle...