MishkaCmsCore.Runtime.Resources.Validations.GlobalRowIsMasterOnly (Mishka CMS Core v0.0.1)

Stops a tenant changing a row that belongs to no site.

What it is for

On a global? true resource a tenant can READ the global rows — that is what global? is for. Nothing in Ash stops them WRITING to one, and for a review note that mattered: a note on a shared component is visible to every site using it, so a tenant closing one would be answering on everybody's behalf about a component they cannot even edit.

Reading is untouched, and so is creating: a tenant's own note is stamped with their site by the tenant create action, so it is never global in the first place. This guards only the actions that change a row that already exists.

Usage

update :resolve do
  validate GlobalRowIsMasterOnly
end

It reads the row's CURRENT site_id — Ash.Changeset.get_data/2, not get_attribute/2 — because the question is what the row is, not what the changeset would like it to become.