ARIA 1.2: Explicit guidance needed for non-pertinent errormessage elements

[joanmarie]

I began implementing support for aria-errormessage in WebKitGtk, but was unsure how user agents should handle aria-errormessage referencing a valid, non-hidden element when that error message has not explicitly been marked as pertinent by the author. In particular:

1. The ARIA spec states, "Authors MUST use aria-invalid in conjunction with aria-errormessage. Initially, the object is in a valid state and either has aria-invalid set to false or no aria-invalid attribute, and the element referenced by aria-errormessage is not applicable."

   Question: What are user agents expected to do when aria-invalid is missing or false, but aria-errormessage references a valid, non-hidden element? Not expose the referenced element at all? Something else?

   Proposal: We should add a normative statement to the ARIA spec explaining the expectations of user agents. I would suggest something like, "User agents MUST NOT expose an element as a pertinent error message when the referencing element lacks aria-invalid="true".

2. The ARIA spec states, "When aria-errormessage is pertinent, authors MUST ensure the content is not hidden and is included in a container that exposes the content to the user as it is expected that the assistive technology user will navigate to the content in order to access it."

   Question: When aria-errormessage is NOT pertinent, there is no statement regarding authors taking steps to cause the error message to be pruned from the accessibility tree. Is there any possibility the author will "hide" it visually in a way that it is still in the accessibility tree? If so, is it up to user agents to figure that condition out from aria-invalid's value? Hopefully not, but if that is the case, see item 1 above.

   Proposal: We should add a normative statement to the ARIA spec instructing authors to take steps to cause the error message to be pruned from the accessibility tree. Something like, "Authors MUST remove the error message when it is not pertinent, either by removing the element's id from aria-errormessage or by ensuring the referenced element is not rendered or has an aria-hidden value of true.

[joanmarie]

Matt during meeting said he didn't like the idea of aria-hidden being set to true because that is not the purpose of aria-hidden="true".

[joanmarie]

"Authors MUST remove the error message when it is not pertinent, either by removing the aria-errormessage attribute or its value, or by ensuring the referenced element is not rendered."

[joanmarie]

The changes here are normative, and the "1.1" label/target was set so that we'd include these changes if the Working Group consensus was to exit and re-enter CR. The other issues which would make exiting and re-entering CR desirable proved to be non-issues. The subsequent agreement of the Working Group was to postpone this particular issue to 1.2. Updating the issue accordingly.

[mcking65]

Thinking about the APG requirement for this for w3c/aria-practices#564 and not sure why the authoring statement is a MUST instead of a SHOULD.

We have the requirement:

User agents MUST NOT expose an element as a pertinent error message when the referencing element lacks aria-invalid set to true.

So, if aria-invalid is not true, then the error message relationship is not exposed, right? Then, what is the practical implication of the author including aria-errormessage when aria-invalid is not true? We have this requirement:

When aria-errormessage is not pertinent, authors MUST either ensure the content is not rendered or remove the aria-errormessage attribute or its value.

Obviously, not rendering an error message that is not pertanent, regardless of whether or not there is a relationship, is very important.

A common scenario is:

• author renders div with descriptive info and it is referenced by aria-describedby.
• User makes invalid input.
• The div that had description now has error message and is referenced by aria-errormessage.

1. Is there any practical implication to leaving the aria-errormessage relationship in place regardless of state of invalid?
2. Should the author make sure that errormessage and describedby do not point to the same thing at the same time?