Align wide/full missing when using theme.json

[tomusborne]

Description

It's been reported that themes using theme.json do not display the align wide/full option in the Container block.

It seems block themes don't use add_theme_support, which GB depends on checking to add this option: https://fullsiteediting.com/lessons/global-styles/#h-layout-and-content-width

The reason we check for support and add it instead of using the built-in way of adding it is because we don't want Container blocks inside the Grid to have the option.

Steps to reproduce

1. Add a block theme
2. Check the Container block for full/wide alignment options.

Expected behavior

The option should appear if the block theme supports it.

Actual behavior

The option doesn't appear.

References:

• https://wordpress.org/support/topic/container-alignment-option-missing-if-theme-json-exists/#post-14726447

[tomusborne]

Might be better to use getThemeSupports(): https://github.com/WordPress/gutenberg/blob/3da717b8d0ac7d7821fc6d0475695ccf3ae2829f/packages/editor/src/components/theme-support-check/index.js#L41

[illycz]

I'm using Underscores and experimenting within global styles defined throu theme.json.

When I have theme.json in my theme, align wide and align full options missing in all blocks. I have set theme support for align-wide in functions.php. Options missing also when I set layout settings in theme.json and remove support from functions.php.

It looks like Gutenberg problem...

Any suggestion?

Thanks