Excerpt: Honor the visibility block support when generating excerpts.

src/wp-includes/blocks.php

@@ -2238,6 +2238,14 @@ function excerpt_remove_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 ) ) {
@@ -2299,6 +2307,14 @@ function _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;
 		}

tests/phpunit/tests/formatting/excerptRemoveBlocks.php

@@ -129,4 +129,82 @@ public function test_excerpt_infinite_loop() {
 		$query->the_post();
 		$this->assertEmpty( do_blocks( '<!-- wp:core/fake /-->' ) );
 	}
+
+	/**
+	 * Tests that a top-level block hidden via the visibility block support
+	 * is removed from the excerpt.
+	 *
+	 * @ticket 65456
+	 */
+	public function test_excerpt_remove_blocks_skips_hidden_block() {
+		$content = '<!-- wp:paragraph {"metadata":{"blockVisibility":false}} -->
+<p>hidden</p>
+<!-- /wp:paragraph -->
+<!-- wp:paragraph --><p>visible</p><!-- /wp:paragraph -->';
+
+		$output = excerpt_remove_blocks( $content );
+
+		$this->assertStringNotContainsString( 'hidden', $output );
+		$this->assertStringContainsString( 'visible', $output );
+	}
+
+	/**
+	 * Tests that a hidden wrapper block (group/columns/column) is removed
+	 * from the excerpt, including its inner blocks.
+	 *
+	 * @ticket 65456
+	 *
+	 * @covers ::_excerpt_render_inner_blocks
+	 */
+	public function test_excerpt_remove_blocks_skips_hidden_wrapper_block() {
+		$content = '<!-- wp:group {"metadata":{"blockVisibility":false}} -->
+<div class="wp-block-group">
+<!-- wp:paragraph --><p>hidden inside group</p><!-- /wp:paragraph -->
+</div>
+<!-- /wp:group -->
+<!-- wp:paragraph --><p>visible</p><!-- /wp:paragraph -->';
+
+		$output = excerpt_remove_blocks( $content );
+
+		$this->assertStringNotContainsString( 'hidden inside group', $output );
+		$this->assertStringContainsString( 'visible', $output );
+	}
+
+	/**
+	 * Tests that a hidden block nested inside a visible wrapper is removed.
+	 *
+	 * @ticket 65456
+	 *
+	 * @covers ::_excerpt_render_inner_blocks
+	 */
+	public function test_excerpt_remove_blocks_skips_hidden_inner_block() {
+		$content = '<!-- wp:group -->
+<div class="wp-block-group">
+<!-- wp:paragraph {"metadata":{"blockVisibility":false}} --><p>hidden inner</p><!-- /wp:paragraph -->
+<!-- wp:paragraph --><p>visible inner</p><!-- /wp:paragraph -->
+</div>
+<!-- /wp:group -->';
+
+		$output = excerpt_remove_blocks( $content );
+
+		$this->assertStringNotContainsString( 'hidden inner', $output );
+		$this->assertStringContainsString( 'visible inner', $output );
+	}
+
+	/**
+	 * Tests that a block hidden only on a specific viewport is kept in the
+	 * excerpt. Viewport visibility only affects the rendered display via CSS,
+	 * so it must not strip the block's text from the excerpt.
+	 *
+	 * @ticket 65456
+	 */
+	public function test_excerpt_remove_blocks_keeps_viewport_hidden_block() {
+		$content = '<!-- wp:paragraph {"metadata":{"blockVisibility":{"viewport":{"desktop":false}}}} -->
+<p>Hello World</p>
+<!-- /wp:paragraph -->';
+
+		$output = excerpt_remove_blocks( $content );
+
+		$this->assertStringContainsString( 'Hello World', $output );
+	}
 }