findLinkDest() searching in parent nodes

[hugtalbot]

First noticed in #3339 canCreate() in TopologicalMapping calls findLinkDest() which checks the link at creation and if not found, the search continues in parent nodes.

findLinkDestClass(const sofa::core::objectmodel::BaseClass* destType, const std::string& path, const sofa::core::objectmodel::BaseLink* link) override;

is looking for the class in the given path and if not found is looking in the parent Node.

So for example in this code:

    BaseMeshTopology* stin;
    inPath = "@../";
    context->findLinkDest(stin, inPath , nullptr);
    
    BaseMeshTopology* stout;
    outPath = "@./";
    context->findLinkDest(stout, outPath, nullptr);

if no MeshTopology is present in ./ for the output mesh, it can return a "valid" pointer to a mesh in the parent Node. Therefor you end up with the same topology in Input and Output.

Do you think it is a behavior error of findLinkDestClass or a bad usage in this case ?

@epernod @damienmarchal @fredroy

[damienmarchal]

In general I think that explicit link is the way to go.
Automatic deduction in the current node is acceptable but searching in the full hierarchy is going far too much.

I would recommend to deprecate that feature, and progressively remove it.

EDIT: I was thinking to make a small PR to fix that...and well...after having looked at the code it is, as often, going to be a noodle untangling task.