// The root artifact may, or may not be resolved so we need to check before we attempt to resolve.
        // This is often an artifact like a POM that is taken from disk and we already have hold of the
        // file reference. But this may be a Maven Plugin that we need to resolve from a remote repository
        // as well as its dependencies.

import static org.apache.maven.internal.impl.Utils.nonNull;

@Named
@Singleton
public class DefaultArtifactResolver implements ArtifactResolver {

    @Override
    public ArtifactResolverResult resolve(ArtifactResolverRequest request)
            throws ArtifactResolverException, IllegalArgumentException {
        nonNull(request, "request");
        InternalSession session = InternalSession.from(request.getSession());