ElementLink: consider empty containers in isValid
Make isValid
return false in case the ElementLink
points into an
empty container.
Also had to add an empty()
method to IdentifiableContainerMT
to satisfy this new requirement.
This use-case comes up in the Trigger EDM deserialization where we try to restore missing containers during reconstruction (e.g. because they were forgotten to be serialized during data-taking, see !65540 (comment 7078959)). However, there might be ElementLinks
pointing to these (now empty) containers.
Edited by Frank Winklmeier