Forms: allow previewing and modifying validation errors

[simison]

I used the block settings to change the color of the text to a different color, but you can’t change the error text color without css.

It'll probably make sense to have some mechanism to allow previewing fields in error state, and then have typography+color controls for them separately.

Internal ref p1737033540877189-slack-C0197R4UB4J

[github-actions]

This issue could use some more labels, to help prioritize and categorize our work. Could you please add at least a [Type], a [Feature], and a [Pri] label?

[simison]

One idea from Gutenberg forms experimentation:

[talldan]

Just to link the two things together, this also came up when trying to enable more layouts for forms. (#41805 (comment))

It seems the main validation message is auto-inserted before the submit button, so if you were able to move the button into say a row block, that would result in the validation message being awkwardly placed and cause issues with the layout:

Turning the validation message into a block would be cool. The form perhaps doesn't need to have this by default (the message could be rendered as it is now when the block is not present, perhaps via the block hooks feature), but when added it could allow custom positioning of the messages and further customization.

[simison]

Not directly applicable but Woo's notices convo is interesting to check in case ideas come up.

[simison]

perhaps via the block hooks feature), but when added it could allow custom positioning of the messages and further customization.

Mandatory child blocks feels more fitting as block hooks are something you can toggle off.

The whole validation UX needs attention as we should rely much more to inline validation errors directly in the fields, not a separate area as much.

Thus separate UX for "success" and "validation errors" might make sense.