Set ignoredHookedBlocks metadata

src/wp-includes/blocks.php

@@ -758,6 +758,20 @@ function get_hooked_blocks() {
 }
 
 function get_hooked_block_markup( &$anchor_block, $hooked_block_type ) {
+	if (
+		isset( $anchor_block['attrs']['metadata']['ignoredHookedBlocks'] ) &&
+		in_array( $hooked_block_type, $anchor_block['attrs']['metadata']['ignoredHookedBlocks'] )
+	) {
+		return '';
+	}
+
+	// The following is only needed for the REST API endpoint.
+	// However, its presence does not affect the frontend.
+	if ( ! isset( $anchor_block['attrs']['metadata']['ignoredHookedBlocks'] ) ) {
+		$anchor_block['attrs']['metadata']['ignoredHookedBlocks'] = array();
+	}
+	$anchor_block['attrs']['metadata']['ignoredHookedBlocks'][] = $hooked_block_type;
+
 	return get_comment_delimited_block_content( $hooked_block_type, array(), '' );
 }
 

tests/phpunit/tests/blocks/getHookedBlockMarkup

@@ -21,6 +21,7 @@ class Tests_Blocks_GetHookedBlockMarkup extends WP_UnitTestCase
 		);
 
 		$actual = get_hooked_block_markup( $anchor_block, 'tests/hooked-block' );
+		$this->assertSame( array( 'tests/hooked-block' ), $anchor_block['attrs']['metadata']['ignoredHookedBlocks'] );
 		$this->assertSame( '<!-- wp:tests/hooked-block /-->', $actual );
 	}
 }