"aria-valid-attr-value" failure on aria-describedby with more than one IDREF

[iamrafan]

Current:

aria-valid-attr-value currently passes only if all the IDREFs on aria-describedby are available or valid. It fails if at least one of the IDREFs is not available

Expected:

The rule should pass or show up as needs review if at least of the IDREFs is valid and available, as some content is available to the ATs

Case-3 and Case-4 in the demo attached should pass instead of failing the aria-valid-attr-value

Demo: aria-describedby with multiple IDREFs tests.zip

axe-core version: 3.0.0-beta.3
axe-Coconut version: 3.3.0-beta.0

[marcysutton]

I validated the experience with only one valid IDREF out of two works fine in Voiceover for OSX and iOS, NVDA and JAWS.

[iamrafan]

The change should also be applicable to aria-labelledby having only one valid IDREF, out of two or more

[dylanb]

We should split this into two separate rules - one that complains if all are not available and one that is a best practice, that complains if only one of multiple is not available

[WilcoFiers]

I spoke to Wendy about this one at AccessU. The story behind it is that they've got one of two labels that they can show for an element. The aria-describedby is static, and by rendering one or the other target they toggle the description. There is nothing inaccessible about this, so this is a false positive. I'm going to treat it as such and change the existing rule to allow this. Whether or not we add a best practice to test that all IDREFs exist is a discussion for another topic.

[dylanb]

@WilcoFiers I agree with this but I also think we should add a needs review rule because while this may be ok, it also might be a mis-spelling and we miss a big opportunity to help developers identify this