I am planning to autogenerate a set of Java libs from OpenAPI 3.1 definitions in an upcoming project, and so far have assumed it would Just Work. Am I going to have a bad time?
The OpenAPI Generator uses Mustache templates and a plug-in-style design to handle all the different languages and outputs targeting different packages. I was never able to find a succinct document explaining exactly how the processing steps worked or even a catalog of data elements that the generator extracted from your OpenAPI spec document (YAML or JSON). So while there's a lot of talk about creating a custom template, or, if that's not enough, a custom generator... the documentation to do so is very incomplete. The only example I found all discussed making a generator for documentation and not code. Again, not to sound unappreciative, but... that's lame.