Do we want to write metadata to the output file, and what do we want to write?
We are able to output configuration metadata and such to text files, but it might be useful to actually pop this inside the output ROOT file. A few details come to mind:
- The analysis flags (or even the full config object) could be stored in a string. Merging rule: assert that configs are identical.
- The list of systematics would be useful for looping over. Although it's implicit in collection branch names, we would have to collect this over all collections. Merging rule: probably also assert that the set is identical (disjoint is an interesting option, but requires that all branches also be disjoint and event ordering is identical, so rather tricky).
More suggestions welcome...
CutBookKeeper info is fine in histograms as is.