aria-details precedence over aria-describedby

[jongund]

In the definition of aria-details has the following statement about the precedence of aria-details over aria-describedby:

"In some user agents, multiple reference relationships for descriptive information are not supported by the accessibility API. In such cases, if both aria-describedby and aria-details are provided on an element, aria-details takes precedence."

The CORE AAM for aria-details and aria-describedby tells an interesting story:

1. The mappings seem to be independent of each other except for UIA, so are processing instructions needed to be included to enforce the precedence of aria-details? Can the mapping be updated for UIA to make them independent?
2. What is more concerning is there is no mapping for aria-details for AX API, which means using this property will be useless to users of macOS. If anything shouldn't we be giving precedence to aria-describedby which is supported on all platforms?

[jnurthen]

@cookiecrook At TPAC you seemed amenable to getting a mapping for aria-details into AX API. Can we get a path forwards on this so we can resolve this issue particularly in regards to the ongoing work on ARIA Annotations.

[cookiecrook]

My comment was that original use cases for aria-details were questionable like longdesc or aria-describedat, but that the annotations use case mentioned for document suites has merit. @aleventhal is proposing this use for Google Docs.

[jnurthen]

Correct - any chance we can get some mappings for AX API so we can resolve at least half of this issue? I can log an issue against core-aam and assign to you if that would help.

[cookiecrook]

https://bugs.webkit.org/show_bug.cgi?id=165842

[pkra]

I think this can be closed now. The problematic wording is no longer in the spec. Instead it reads

If a user agent relies on an accessibility API that does not support exposing multiple descriptive relations, and if an element has both aria-details and aria-describedby, the user agent SHOULD expose the aria-details relation and the description string computed from the aria-describedby relationship.

For the point about core-aam listing AX API as not mapped I filed w3c/core-aam#88.