Introduce Behaviors UI

[czapla]

Adds the Behaviors UI, which is a simple UI element to add specific behaviors to a block and support for them to theme.json & block.json. It is only concerned with the built-in "LIGHTBOX" behavior.

Merges from Gutenberg.

Reference:

• ​https://github.com/WordPress/gutenberg/pull/49972/

Backport the PR that introduced the Behaviors UI in the block editor:

• ​https://github.com/WordPress/gutenberg/pull/49972/

Trac ticket: https://core.trac.wordpress.org/ticket/58431

[czapla]

I don't seem to have sufficient permissions to edit the description to add additional information, sorry!

@michalczaplinski Aside from the WPCS issues, the unit tests are failing because the behaviors.php file isn't included. This should probably be added in wp-settings.php, but I am not 100% sure where this would best fit.

Ok, fixed it.

should probably be added in wp-settings.php, but I am not 100% sure where this would best fit.

I'm also not 100% sure if this is the best place, but I've put it there like you suggested.

[tb1909]

Test Report

This report validates that the indicated patch addresses the issue.

Patch tested: https://core.trac.wordpress.org/ticket/58431?action=diff&version=5

Environment

• OS: macOS 13.4
• Web Server: Nginx
• PHP: 8.1.13
• WordPress: 6.3-alpha-55505-src
• Browser: Google Chrome 114.0.5735.106
• Theme: Twenty Twenty-Three
• Active Plugins:
  • none

Actual Results

• Unable to see the lightbox dropdown menu

Additional Notes

• Tried the following: Creating a new post, adding an image, opening up the advanced section. The dropdown menu does not show up. After manually adding the

"core/image": {
	"behaviorsUIEnabled": true
},

, and

"behaviors": {
	"lightbox": true
}

to the theme.json of the twenty-twentythree theme it still does not show up

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We can close this backport as it will be punted for 6.4 - I guess for that time there will be different code.

It looks like this will be postponed until 6.4.

See @c4rl0sbr4v0's comment: ​https://github.com/WordPress/gutenberg/issues/51077#issuecomment-1593272413

[mikeschroder]

Based on the comments in the PR, I'm going to move this to the 6.4 milestone.

Thanks so much everyone for your help so far!

If I misunderstand, or the decision is changed, please feel free to comment and move it back into 6.3.

[hellofromTonya]

Removed the word "Backport" as this means something different in Core (it means to backport changes to an older Core branch / version).

Updated the description from the original Gutenberg PR to provide more information for contributors working on merging the code from Gutenberg into Core.

Behaviors have been removed from the Gutenberg plugin in ​https://github.com/WordPress/gutenberg/pull/53851.

An updated implementation of the Image Lightbox has been created in ​https://github.com/WordPress/gutenberg/pull/54509 where the Lightbox is not a Behavior but a feature of the Image block.

The above PRs have a corresponding backport in ​https://github.com/WordPress/wordpress-develop/pull/5248

In the light of all that, we can now close this PR.

[czapla]

As noted in the above comment on the PR, this is superseded by https://core.trac.wordpress.org/ticket/59393