Despite configuring AlwaysAddARHeader to true/1, when a From header is missing OpenDKIM logs "can't determine message sender; accepting" and no header is added. In this situation it should still add and AR header (appropriately failing it). It's impossible to use the AR header for filter/decision making if the behaviour isn't consistent.
Steps to Reproduce:
Push a message through verify missing a From header
Requested behaviour modifications:
Add an AR header, always, even if there are RFC violations. Certainly violations / missing requirements will result in AR failing, but that is what we want to see.