Should aria-required be supported on radio buttons instead of (or in addition to) radio groups?

[joanmarie]

While doing some work in Chromium related to ARIA, I discovered that Chromium was treating aria-required as a global attribute. When I changed that to be compliant with the spec, a test related to reporting aria-required on radio buttons failed.

Doing some digging, I discovered:

• The test I broke had landed as part of this commit whose commit message states manually testing with JAWS, NVDA, and VoiceOver was performed. This makes me wonder if those screen readers are supporting (perhaps even expecting?) aria-required to be supported on radio buttons. (Orca checks the radio button first and if the state is absent, checks the group.)
• Chromium inherited the code in AXNodeObject:IsRequired() from WebKit.
• Unlike Chromium, WebKit checks to see if required is a supported property before exposing it. BUT if you look at the list of roles in AXCoreObject::supportsRequiredAttribute() you'll see that radio button is there along with radio group.
• Looking at Firefox, it appears that aria-required is among the non-global ARIA states Gecko treats as global. There's even a code comment indicating aria-required is not global and pointing to this bug that doesn't appear to be a high priority.

I personally don't have any opinion. But the spec and the implementations are not in sync.

[yatil]

Technically, I think when you have radio buttons, one button should always be selected by default. So the group will always have a value, and aria-required would not be… required. That said, at some point people started to use radio buttons, which have no default selection, which does not make sense to me, as you cannot unset a radio group anyway. So there is no way to go back to the initial value (apart from abandoning the form).

I wished the spec and maybe browsers could make it more clear that radio button groups without an initial selection are a bad practice?

[SaraSoueidan]

Opinion: I think it doesn't make much sense to mark a single or multiple radio buttons in a group as required, knowing that only one of them—any one of them—can be selected.

I agree with @yatil that there must always be at least one selected in a group of radio buttons. Enforcing that somehow makes more sense than setting aria-required on individual buttons within a group.

After all, the radio buttons get treated as one tab stop, which means the group itself is treated as one item. So it makes sense that the aria-required attribute be set on the group.