Description

Error messages need to have an explicit connection to the field that generated the error. The input validation on the link control displays a message which is announced using aria-live, but is not connected to the input. While this will serve in most cases, it will be a problem if the user misses the announcement for any reason (it's overridden by another message, just missed because of distraction, etc.). It won't be announced if the user navigates away from the field (e.g., to the submit button), and then navigates back.

Two suggestions:

1. Explicitly connect the two fields by using aria-describedby with the ID attribute of the error message.
2. Announce the message through a11y.speak() instead of adding a new aria-live region specifically for that message.

Step-by-step reproduction instructions

1. Add a paragraph with text.
2. Select text and add a Link
3. Enter a non-URL string like 'test' in the field and click 'Submit' or press the 'Enter' key.
4. Note the appended text with the invalid URL error message with no ID connection to the input.

Screenshots, screen recording, code snippet

(Note: the image is using the Text Controls mode in the admin, which also exposes issues with the submit button text, which is unrelated to this issue.)

Environment info

• 7.0-beta5-62067

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure