Excerpt: Honor the visibility block support when generating excerpts.

[t-hamano]

Trac ticket: https://core.trac.wordpress.org/ticket/65456

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 4.8
Used for: Investigating the excerpt rendering path, implementing the fix, and drafting the tests. All changes were reviewed and edited by me.

---

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[Copilot]

Pull request overview

This PR updates WordPress’s excerpt generation path to respect the block visibility support when assembling excerpts from parsed blocks, so content hidden via metadata.blockVisibility does not leak into generated excerpts (especially for wrapper blocks where excerpts are built from innerBlocks).

Changes:

• Skip blocks (top-level and nested) marked hidden via visibility support while building excerpt output.
• Add PHPUnit coverage for hidden top-level blocks, hidden wrapper blocks (group/columns/column), hidden inner blocks, and viewport-only hidden configuration.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/wp-includes/blocks.php	Skips hidden blocks during excerpt rendering for both top-level blocks and recursive innerBlocks traversal.
tests/phpunit/tests/formatting/excerptRemoveBlocks.php	Adds tests asserting hidden blocks are removed from excerpts, including wrapper/nested scenarios and viewport-only visibility.

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[ramonjd]

I guess this is an edge case - the attributes are there, but the block doesn't have support for visibility. What do you think @t-hamano

[t-hamano]

It was actually intentional that I didn't check if the block had block support. This is because if visibility support is later disabled for the block, its content could leak.

This logic aligns with the visibility support logic.

• Block Visibility: Keep hide-everywhere working after a block opts outof visibility support #12053
• Block Visibility: Keep hide-everywhere working after a block opts out of visibility support gutenberg#78780

However, the comments were not accurate, so I improved them.

[ramonjd]

Thanks for the explainer!

Aki -1
Copilot - 0

[ramonjd]

Works well. Thanks a lot for the patch @t-hamano

I checked the editor as well. A couple of questions came up:

• How should we handle viewport breakpoints? A bit of a rhetorical question really as I think it's fine as it is. Hidden blocks aren't rendered, whereas viewport block are and are in the HTML content, and therefore should be in the excerpt.
• Do you think we'll need a GB patch as well?

Before

After

[t-hamano]

@ramonjd Thanks for the review!

Hidden blocks aren't rendered, whereas viewport block are and are in the HTML content, and therefore should be in the excerpt.

I agree. Since the content is dynamically controlled by CSS on the front end, the server cannot determine whether to hide the content. It is reasonable to always output the excerpt.

Do you think we'll need a GB patch as well?

This PR directly updates core functionality, so it may be difficult to apply compatible code to GB. When I tried asking an AI, it indicated that the following extensive code would be necessary 😅

Details

<?php
/**
 * Honor the visibility block support when generating excerpts.
 *
 * Backports https://github.com/WordPress/wordpress-develop/pull/12167 (Trac #65456).
 *
 * Core's excerpt_remove_blocks() / _excerpt_render_inner_blocks() are not
 * pluggable and have no per-block extension point, so the only way to inject
 * the visibility check is to replace wp_trim_excerpt() on the
 * `get_the_excerpt` filter with a Gutenberg copy that calls our excerpt
 * functions. Remove this file once the change ships in WordPress Core.
 *
 * @package gutenberg
 */

/**
 * Gutenberg copy of excerpt_remove_blocks() that skips blocks hidden via the
 * visibility block support (`metadata.blockVisibility === false`).
 *
 * @param string $content The content to filter.
 * @return string The filtered content.
 */
function gutenberg_excerpt_remove_blocks( $content ) {
	if ( ! has_blocks( $content ) ) {
		return $content;
	}

	$allowed_inner_blocks = array(
		// Classic blocks have their blockName set to null.
		null,
		'core/freeform',
		'core/heading',
		'core/html',
		'core/list',
		'core/media-text',
		'core/paragraph',
		'core/preformatted',
		'core/pullquote',
		'core/quote',
		'core/table',
		'core/verse',
	);

	$allowed_wrapper_blocks = array(
		'core/columns',
		'core/column',
		'core/group',
	);

	/** This filter is documented in wp-includes/blocks.php */
	$allowed_wrapper_blocks = apply_filters( 'excerpt_allowed_wrapper_blocks', $allowed_wrapper_blocks );

	$allowed_blocks = array_merge( $allowed_inner_blocks, $allowed_wrapper_blocks );

	/** This filter is documented in wp-includes/blocks.php */
	$allowed_blocks = apply_filters( 'excerpt_allowed_blocks', $allowed_blocks );
	$blocks         = parse_blocks( $content );
	$output         = '';

	foreach ( $blocks as $block ) {
		// Hide the block whenever the value is boolean false, regardless of the
		// block's current visibility support. This prevents blocks that previously
		// supported visibility from unintentionally appearing on the front end
		// after their support was disabled.
		if ( false === ( $block['attrs']['metadata']['blockVisibility'] ?? null ) ) {
			continue;
		}

		if ( in_array( $block['blockName'], $allowed_blocks, true ) ) {
			if ( ! empty( $block['innerBlocks'] ) ) {
				if ( in_array( $block['blockName'], $allowed_wrapper_blocks, true ) ) {
					$output .= gutenberg_excerpt_render_inner_blocks( $block, $allowed_blocks );
					continue;
				}

				// Skip the block if it has disallowed or nested inner blocks.
				foreach ( $block['innerBlocks'] as $inner_block ) {
					if (
						! in_array( $inner_block['blockName'], $allowed_inner_blocks, true ) ||
						! empty( $inner_block['innerBlocks'] )
					) {
						continue 2;
					}
				}
			}

			$output .= render_block( $block );
		}
	}

	return $output;
}

/**
 * Gutenberg copy of _excerpt_render_inner_blocks() that skips inner blocks
 * hidden via the visibility block support.
 *
 * @param array $parsed_block   The parsed block.
 * @param array $allowed_blocks The list of allowed inner blocks.
 * @return string The rendered inner blocks.
 */
function gutenberg_excerpt_render_inner_blocks( $parsed_block, $allowed_blocks ) {
	$output = '';

	foreach ( $parsed_block['innerBlocks'] as $inner_block ) {
		// Hide the block whenever the value is boolean false, regardless of the
		// block's current visibility support. This prevents blocks that previously
		// supported visibility from unintentionally appearing on the front end
		// after their support was disabled.
		if ( false === ( $inner_block['attrs']['metadata']['blockVisibility'] ?? null ) ) {
			continue;
		}

		if ( ! in_array( $inner_block['blockName'], $allowed_blocks, true ) ) {
			continue;
		}

		if ( empty( $inner_block['innerBlocks'] ) ) {
			$output .= render_block( $inner_block );
		} else {
			$output .= gutenberg_excerpt_render_inner_blocks( $inner_block, $allowed_blocks );
		}
	}

	return $output;
}

/**
 * Gutenberg copy of wp_trim_excerpt() that routes block removal through
 * gutenberg_excerpt_remove_blocks() so hidden blocks are stripped from
 * auto-generated excerpts.
 *
 * Identical to core wp_trim_excerpt() except for the excerpt_remove_blocks()
 * call, which is swapped for gutenberg_excerpt_remove_blocks().
 *
 * @param string      $text The trimmed text.
 * @param WP_Post|int $post The post.
 * @return string The trimmed excerpt.
 */
function gutenberg_trim_excerpt( $text = '', $post = null ) {
	$raw_excerpt = $text;

	if ( '' === trim( $text ) ) {
		$post = get_post( $post );
		$text = get_the_content( '', false, $post );

		$text = strip_shortcodes( $text );
		$text = gutenberg_excerpt_remove_blocks( $text );
		$text = excerpt_remove_footnotes( $text );

		/*
		 * Temporarily unhook wp_filter_content_tags() since any tags
		 * within the excerpt are stripped out. Modifying the tags here
		 * is wasteful and can lead to bugs in the image counting logic.
		 */
		$filter_image_removed = remove_filter( 'the_content', 'wp_filter_content_tags', 12 );

		/*
		 * Temporarily unhook do_blocks() since excerpt_remove_blocks( $text )
		 * handles block rendering needed for excerpt.
		 */
		$filter_block_removed = remove_filter( 'the_content', 'do_blocks', 9 );

		/** This filter is documented in wp-includes/post-template.php */
		$text = apply_filters( 'the_content', $text );
		$text = str_replace( ']]>', ']]&gt;', $text );

		// Restore the original filter if removed.
		if ( $filter_block_removed ) {
			add_filter( 'the_content', 'do_blocks', 9 );
		}

		/*
		 * Only restore the filter callback if it was removed above. The logic
		 * to unhook and restore only applies on the default priority of 10,
		 * which is generally used for the filter callback in WordPress core.
		 */
		if ( $filter_image_removed ) {
			add_filter( 'the_content', 'wp_filter_content_tags', 12 );
		}

		/* translators: Maximum number of words used in a post excerpt. */
		$excerpt_length = (int) _x( '55', 'excerpt_length' );

		/** This filter is documented in wp-includes/formatting.php */
		$excerpt_length = (int) apply_filters( 'excerpt_length', $excerpt_length );

		/** This filter is documented in wp-includes/formatting.php */
		$excerpt_more = apply_filters( 'excerpt_more', ' ' . '[&hellip;]' );
		$text         = wp_trim_words( $text, $excerpt_length, $excerpt_more );
	}

	/** This filter is documented in wp-includes/formatting.php */
	return apply_filters( 'wp_trim_excerpt', $text, $raw_excerpt );
}

// Replace core's excerpt trimmer with the visibility-aware version.
remove_filter( 'get_the_excerpt', 'wp_trim_excerpt', 10 );
add_filter( 'get_the_excerpt', 'gutenberg_trim_excerpt', 10, 2 );

[github-actions]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 62539
GitHub commit: 18bf527

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.