Tristan made a good point, part of the doc building process performs a resolving check and circular reference check, which is ignored by the returned errors. So resolving errors are now unpacked into standard errors and returned. Not sure why gofmt has shifted everything around however.
The v3 model is wrong and out of sync with the spec. It's been corrected, so the v2 and v2 model for SecurityRequirement have been collapsed down into a base model., they are the same data structures. This has allowed me to delete the complexity of sharing two different models for the same structure, by unifying the model correctly. I am not sure why I decided to change the v3 model, oh well, its been corrected. Long live swagger!
3.0 and 2.0 do not work, there are multiple versions and anything with a period in it sucks from my point of view, v2 and v3 feel much better from a DX perspective.