Attributes, Supports and InnerBlocks

lumen-catalog/src/
├── Blocks.php              # registers build/blocks/ from blocks-manifest.php
├── BookShelfContext.php    # new: applies the shelf's context on the front end
└── blocks/
    ├── book-card/          # existing static block; gains "usesContext": [ "lumen/showIsbn" ]
    └── book-shelf/         # new: block.json, index.js, edit.js, save.js, style.scss

import { __ } from '@wordpress/i18n';
import {
	BlockControls,
	InspectorControls,
	RichText,
	useBlockProps,
	useInnerBlocksProps,
} from '@wordpress/block-editor';
import {
	PanelBody,
	TextControl,
	TextareaControl,
	ToolbarButton,
	ToolbarGroup,
} from '@wordpress/components';

const TEMPLATE = [
	[ 'lumen/book-card', { title: 'The Lighthouse Ledger' } ],
	[ 'lumen/book-card', { title: 'The Glass Orchard' } ],
];

export default function Edit( { attributes, setAttributes } ) {
	const { heading, intro, badges, moreUrl, moreLabel, showIsbn } = attributes;
	const blockProps = useBlockProps();
	const innerBlocksProps = useInnerBlocksProps(
		{ className: 'wp-block-lumen-book-shelf__books' },
		{
			allowedBlocks: [ 'lumen/book-card' ],
			template: TEMPLATE,
			templateLock: false,
			orientation: 'horizontal',
		}
	);

	return (
		<>
			<BlockControls group="other">
				<ToolbarGroup>
					<ToolbarButton
						icon="tag"
						label={ __( 'Show ISBNs', 'lumen-catalog' ) }
						isPressed={ showIsbn }
						onClick={ () =>
							setAttributes( { showIsbn: ! showIsbn } )
						}
					/>
				</ToolbarGroup>
			</BlockControls>
			<InspectorControls>
				<PanelBody title={ __( 'Shelf', 'lumen-catalog' ) }>
					<TextareaControl
						__nextHasNoMarginBottom
						label={ __( 'Badges (one per line)', 'lumen-catalog' ) }
						value={ badges
							.map( ( badge ) => badge.label )
							.join( '\n' ) }
						onChange={ ( value ) =>
							setAttributes( {
								badges: value
									.split( '\n' )
									.filter( Boolean )
									.map( ( label ) => ( { label } ) ),
							} )
						}
					/>
					<TextControl
						__next40pxDefaultSize
						__nextHasNoMarginBottom
						label={ __( 'All books link', 'lumen-catalog' ) }
						value={ moreUrl }
						onChange={ ( value ) =>
							setAttributes( { moreUrl: value } )
						}
					/>
					<TextControl
						__next40pxDefaultSize
						__nextHasNoMarginBottom
						label={ __( 'Link text', 'lumen-catalog' ) }
						value={ moreLabel }
						onChange={ ( value ) =>
							setAttributes( { moreLabel: value } )
						}
					/>
				</PanelBody>
			</InspectorControls>
			<section { ...blockProps }>
				<RichText
					tagName="h2"
					className="wp-block-lumen-book-shelf__heading"
					value={ heading }
					onChange={ ( value ) =>
						setAttributes( { heading: value } )
					}
					placeholder={ __( 'Shelf title', 'lumen-catalog' ) }
				/>
				<RichText
					tagName="p"
					className="wp-block-lumen-book-shelf__intro"
					value={ intro }
					onChange={ ( value ) => setAttributes( { intro: value } ) }
					allowedFormats={ [
						'core/bold',
						'core/italic',
						'core/link',
					] }
					placeholder={ __( 'Introduction', 'lumen-catalog' ) }
				/>
				{ badges.length > 0 && (
					<ul className="wp-block-lumen-book-shelf__badges">
						{ badges.map( ( badge ) => (
							<li key={ badge.label }>{ badge.label }</li>
						) ) }
					</ul>
				) }
				<div { ...innerBlocksProps } />
				<a className="wp-block-lumen-book-shelf__more" href={ moreUrl }>
					{ moreLabel }
				</a>
			</section>
		</>
	);
}

import {
	RichText,
	useBlockProps,
	useInnerBlocksProps,
} from '@wordpress/block-editor';

export default function save( { attributes } ) {
	const { heading, intro, badges, moreUrl, moreLabel } = attributes;
	// Call useBlockProps.save() first: useInnerBlocksProps.save() serializes
	// the inner blocks, which resets the props provider used by useBlockProps.
	const blockProps = useBlockProps.save();
	const innerBlocksProps = useInnerBlocksProps.save( {
		className: 'wp-block-lumen-book-shelf__books',
	} );

	return (
		<section { ...blockProps }>
			<RichText.Content
				tagName="h2"
				className="wp-block-lumen-book-shelf__heading"
				value={ heading }
			/>
			<RichText.Content
				tagName="p"
				className="wp-block-lumen-book-shelf__intro"
				value={ intro }
			/>
			{ badges.length > 0 && (
				<ul className="wp-block-lumen-book-shelf__badges">
					{ badges.map( ( badge ) => (
						<li key={ badge.label }>{ badge.label }</li>
					) ) }
				</ul>
			) }
			<div { ...innerBlocksProps } />
			<a className="wp-block-lumen-book-shelf__more" href={ moreUrl }>
				{ moreLabel }
			</a>
		</section>
	);
}

export default function Edit( { attributes, setAttributes, context } ) {
	const { title, isbn, coverUrl, showIsbn } = attributes;
	const shelfShowsIsbn = context[ 'lumen/showIsbn' ] !== false;
	// The rest of the component is unchanged except the ISBN condition, which becomes
	// { shelfShowsIsbn && showIsbn && isbn && ( <p className="wp-block-lumen-book-card__isbn">{ isbn }</p> ) }
}

<?php
/**
 * Applies the lumen/showIsbn context to saved Book Card markup.
 *
 * @package Lumen\Catalog
 */

namespace Lumen\Catalog;

defined( 'ABSPATH' ) || exit;

/**
 * Hides the ISBN of every Book Card placed in a shelf that turned ISBNs off.
 */
final class BookShelfContext {

	/**
	 * Hooks the filter. Called from Plugin::boot().
	 */
	public static function boot(): void {
		add_filter( 'render_block_lumen/book-card', array( self::class, 'filter_card' ), 10, 3 );
	}

	/**
	 * Removes the ISBN paragraph when the parent shelf provides showIsbn = false.
	 *
	 * @param string    $content  Saved block HTML.
	 * @param array     $block    Parsed block.
	 * @param \WP_Block $instance Block instance; context holds only "usesContext" keys.
	 * @return string Block HTML.
	 */
	public static function filter_card( string $content, array $block, \WP_Block $instance ): string {
		if ( false !== ( $instance->context['lumen/showIsbn'] ?? true ) ) {
			return $content;
		}

		return (string) preg_replace(
			'#<p class="wp-block-lumen-book-card__isbn">.*?</p>#s',
			'',
			$content
		);
	}
}

wp eval '$t = WP_Block_Type_Registry::get_instance()->get_registered( "lumen/book-shelf" ); echo implode( ",", array_keys( $t->attributes ) );'

heading,intro,badges,moreUrl,moreLabel,showIsbn,lock,metadata,align,className,style,backgroundColor,textColor,fontSize,borderColor,layout,anchor