I feel like we keep making the same mistake with these configuration formats. Most of the problems with YAML are the problems that XML had in the early Spring

I feel like we keep making the same mistake with these configuration formats. Most of the problems with YAML are the problems that XML had in the early Spring Java days, and most of those problems stemmed from "programming" by gluing together software via configuration files. This isn't a good pattern regardless of how you format the files. The moment you start to reach for schema definitions and validation for your configuration language, you should consider that a warning sign. We've been down this road before. It does not lead to a good place.