Add a flag to AIDA proc to discard output

[Victor-Schwan]

BEGINRELEASENOTES

• Format files which are modified in the PR
• Add a flag to the AIDA proc to discard output

ENDRELEASENOTES

[Victor-Schwan]

Feel free to drop the formatting commits if you wish to do so

[Victor-Schwan]

Note on testing this:
Due to a hardcoded RPATH in libk4MarlinWrapperPlugins.so pointing to the cvmfs Marlin, the local libMarlin.so must be explicitly preloaded via LD_PRELOAD=/path/to/local/Marlin/install/lib/libMarlin.so k4run ... to ensure the modified processor is picked up at runtime. The new DiscardOutput parameter appearing in the processor's parameter dump at the start of the job confirms that the correct version is loaded. Specifically, this means that k4_local_repo doesn't work.

As far as I can tell, this issue isn't mentioned in the key4hep documentation either, and I think it should be added.

[gaede]

Merge as all relevant checks passed.

[jmcarcell]

Please keep the formatting changes in a separate PR, it makes it very hard to review, and only possible either checking commits individually or using Github's feature not to show whitespace changes (which aren't all the changes). In this case there isn't a .clang-format in this folder, so the "final" formatting changes once there is one may be different ones.

[Victor-Schwan]

I am aware of this general problem, and that is why I created a separate commit for the formatting changes. Since it is reasonably easy to see the changes per commit, Frank did not squash the commits when he merged it, so you can still see the formatting and the actual changes separately. This is the first time I’ve heard about the wish for a separate PR, which I did not consider necessary. This might also be a good moment to add a .clang-format if it makes things easier.

[jmcarcell]

Another PR helps when reviewing because then you only get to see the actual changes, and a PR with only formatting doesn't need reviewing. At the very least it forces one to find out which commits are the important ones to only display the diff for them. If this is not done, even when only displaying non-whitespace changes, formatting can add a lot of changes that need inspection to see that actually nothing has changes. But the ideal way is to do the formatting in a single commit and then add it to .git-blame-ignore-revs (see https://akrabat.com/ignoring-revisions-with-git-blame/, for example) so that it always is ignored in git blame. Even better if formatting is automatic.

[Victor-Schwan]

I strongly agree that automatic formatting would be the best way to move forward :)