HV-920 Adding a regular expression based URL constraint validator which ...

...needs to be configured via XML or via a ConstraintDefinitionContributor
>  That's totally different to have internal method parameters for public API. That I am extending an internal class is an implementation detail imo.

The problem is that any public members from that internal super class become part of the API of the public sub class, thus they leak through.

> Do we agree in skipping the abstract base class and adjusting the manifest to make this all work?

Yes, sounds good to me. Note that you might avoid the redundancy via delegation instead of inheritance (that'd work as the delegate would just be an internal/private member of the public validator, thus not exposing the internal class).