`AlertDialog` renders without `aria-describedby`

[nami8824]

Provide a general summary of the issue here

When using AlertDialog (with role="alertdialog"), the component renders without aria-describedby.

According to the W3C specification, authors SHOULD use aria-describedby on an alertdialog to reference the alert message element in the dialog.
https://www.w3.org/TR/wai-aria-1.2/#alertdialog

🤔 Expected Behavior?

I think one of the following behaviors should be expected:

• AlertDialog automatically assigns an ID to the content element and sets aria-describedby on the dialog to reference it.
• A development warning is shown when a rendered alertdialog lacks aria-describedby

😯 Current Behavior

AlertDialog renders without aria-describedby by default.

💁 Possible Solution

No response

🔦 Context

No response

🖥️ Steps to Reproduce

https://codesandbox.io/p/sandbox/happy-saha-jtm36v?file=%2Fsrc%2FApp.js%3A26%2C1

Version

3.31.0

What browsers are you seeing the problem on?

Chrome

If other, please specify.

No response

What operating system are you using?

macOS

🧢 Your Company/Team

No response

🕷 Tracking Issue

No response

[snowystinger]

Thanks for the issue, it looks like we should have that, we could automatically hook it up to the content slot in v3 and s2. For RAC, maybe a warning is the best we can do in development environment. We do allow the prop already in RAC, but it should be added to v3 and S2 as well probably so people can override the possibly very verbose content. For testing, it appears as though VO does not include the description in the announcement at this time, https://bugs.webkit.org/show_bug.cgi?id=282773 possibly. At least, I wasn't able to get it announcing when I was trying it out. I'm on MacOS 26.4.1.