[bug] remote specs with local references

[matoous]

Hi! Working with libopenapi locally recently I hit an issue when working with a remote specs (e.g. using https://raw.githubusercontent.com/org/repo/main/specs/openapi.yaml) if the specs contain local references. I first load the file using URL, then pass it to NewDocumentWithConfiguration with BaseURL configured to the URL of the file I used minus the filename itself:

doc, err := libopenapi.NewDocumentWithConfiguration(specBytes, &datamodel.DocumentConfiguration{
	BaseURL:          baseURL(*specURL),
	RemoteURLHandler: handler, // GitHub auth, nothing more happening here
})
if err != nil {
	return nil, fmt.Errorf("create document: %v", err)
}

func baseURL(u url.URL) *url.URL {
	dir, _ := path.Split(u.Path)
	u.Path = dir
	u.RawQuery = ""
	return &u
}

When calling:

spec, errs := doc.BuildV3Model()

though I get an error:

cannot resolve reference `../../../schemas/components.yaml#/components/schemas/Device`, it's missing: $schemas['components.yaml$'].components.schemas.Device [827:11]

suggesting that it can't resolve locally referenced file in the remote specs.

I am not sure what exactly is going wrong, but I am happy to contribute if given a few pointers.

Happens at [my org] so I don't have sharable files for replicating this readily available but if necessary, I can try and craft some.