I'm not sure I agree with the change though: we decided to fail fast precisely because we didn't want to miss the fact that some options were going to be ignored. So it sounds consistent that tools would have to add logic to work around that.

The issue is with frameworks that provide some form of support for creating CqlSession instances in a more or less automated way. Take Spring Boot, for instance: the default CassandraProperties bean exposes contact points and local datacenter. These are then automatically applied in CassandraAutoConfiguration. If you are using Astra, the defaults in Spring Boot won't let you connect, and your only option is to actually bypass CassandraAutoConfiguration completely – which, admittedly, defeats the purpose of using Spring Boot in the first place.

(And it's not realistic to offer to add support to Astra directly in Spring Boot: Astra being proprietary and commercial, it's likely that such a contribution would meet some resistance to say the least.)