Lukas Wunner wrote: [..] > So in this case I'm able to dodge the bullet because the empty > signatures/ directory for CMA-incapable devices is only briefly > visible in the series. Nobody will notice unless they apply > only a subset of the series. > > But I want to raise awareness that the inability to hide > empty attribute groups feels awkward. That is fair, it was definitely some gymnastics to only change user visible behavior for new "invisible aware" attribute groups that opt-in while leaving all the legacy cases alone. The concern is knowing when it is ok to call an is_visible() callback with a NULL @attr argument, or knowing when an empty array actually means "hide the group directory". We could add a sentinel value to indicate "I am an empty attribute list *AND* I want my directory hidden by default". However, that's almost identical to requiring a placeholder attribute in the list just to make __first_visible() happy. Other ideas? I expect this issue to come up again because dynamically populated attribute arrays of a statically defined group is a useful mechanism. I might need this in the PCI TSM enabling... but having at least one attribute there is likely not a problem.
