Four versions of the constructor are called by outside code:

The underlying AttrList constructors are called in some locations.

The first version has a direct equivalent in new ClassAds.

The second version has a compatibility version in new ClassAds.

The third version has no equivalent in new ClassAds. There are two callsites. One (ClassAdCollection::GetClassAdRank()) is trivial to rewrite to construct the ad differently. The other (HookPrepareJobClient::hookExited()) can be rewritten in a few hours.

The fourth version has a direct equivalent in new ClassAds.

Developer time: 3-4 hours