DataHandleHolderBase: define semantics for ExtraInputs/Outputs

Define OrderedSet merge semantics for the ExtraInputs and ExtraOutputs properties. The C++ property type is std::unordered_set, so we don't strictly need it to be "ordered" but it does not hurt either (and we do not have a regular set merge semantics defined).

cc @tbold

mentioned in merge request atlas/athena!44473 (merged)

changed milestone to %v36r4

This one is rather important for ATLAS so would be good to get into the next release.

mentioned in issue #114 (closed)

The problem, I would say, is that I have special handling for vector, list, map and unordered_map, but not for other containers, like set and unordered_set.

Looking back at !1066 (comment 3450152) I realize I missed/forgot we could have Gaudi::Property<unordered_set>, so the OrderedSet semantics could be used for it too.

Also not that the name OrderedSet does not stand for sorted set, but it is to set what OrderedDict is to dict: it preserves the order of insertion.

So you prefer to fix this at a more general level? I would agree that having the proper semantics chosen automatically for sets would of course be even better.

Yes, I prefer to extend the regex of types handled by OrderedSetSemantics.

Sounds good. Closing this in favor of !1298 (merged).

mentioned in merge request !1298 (merged)

closed