How do I get Gradle to comply with the properties standard?

Continuing the discussion from Dotted properties in Gradle:

That’s not what I call flexible. This is a serious pain in my backside since I have a massive project I’m trying to convert with a large number of properties files. Since the project is massive, I can’t change the names as converting it is likely to take months and Maven has to continue working. A little backward compatibility would be nice. Also, I can’t get ConfigSlurper to work. IDK why but it’s probably something I’ve not yet learned about Imports. I’m new to both Gradle and Groovy and I don’t see this class available anywhere.

BUG! exception in phase ‘semantic analysis’ in source unit ‘default_profile_dmmqiztond012huu6njr8dkq1’ String index out of range: 22

The implication here, I think, is that ConfigSlurper is broken and can’t handle property names longer than 22 characters. Is that right?