What is the difference between the doctrine of "absolute immunity from discovery" under Section 2 of the California Civil Code?

To declare, as does subdivision (a), that certain matters are absolutely immune from discovery, yet to permit, as would the majority, their disclosure (i.e., "discovery") at trial, not only achieves an absurd result, but renders sterile the immunity provisions of the statute (cf. Schulz v. Superior Court, supra, 66 Cal.App.3d at p. 445, 136 Cal.Rptr. 67) and makes illusory the confidentiality the statute seemingly provides.