Custom CSS cannot be used with original blocks lacking block.json

[nendeb]

Description

While custom CSS appears to be enabled in WordPress 7.0,
it does not function properly with older original blocks lacking block.json.

Please consider either providing backward compatibility support or disabling customCSS entirely.

Step-by-step reproduction instructions

For original blocks without block.json,
the custom CSS input field appears.
Entering CSS works in the admin interface, but viewing the code editor shows the CSS is not applied.

Since the CSS is not applied on the frontend, the display is not correct.

Screenshots, screen recording, code snippet

No response

Environment info

WordPress 7.0-alpha
Theme Twenty Sixteen

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

[Mamaduka]

cc @glendaviesnz

@nendeb, can you share an example block? While block.json is nice to have, it's not required, and the same configuration can be done via PHP.

[nendeb]

cc@glendaviesnz
Thank you.

I'm sorry, but there are no blocks I can share.
What we currently know is
the case where block.json is not used with server-side rendering.

Also, adding

    style: {
        type: ‘object’,
    },

to the attributes makes it display correctly, but I'm not sure if this is correct.

As I mentioned earlier, I believe it is undesirable to force existing blocks that have been functioning normally to be modified simply because they lack a block.json file.

Please consider how to address this.