wp/wp-includes/blocks.php
changeset 19 3d72ae0968f4
parent 18 be944660c56a
child 21 48c4eec2b7e6
--- a/wp/wp-includes/blocks.php	Wed Sep 21 18:19:35 2022 +0200
+++ b/wp/wp-includes/blocks.php	Tue Sep 27 16:37:53 2022 +0200
@@ -20,10 +20,14 @@
 	if ( 0 !== strpos( $asset_handle_or_path, $path_prefix ) ) {
 		return $asset_handle_or_path;
 	}
-	return substr(
+	$path = substr(
 		$asset_handle_or_path,
 		strlen( $path_prefix )
 	);
+	if ( strpos( $path, './' ) === 0 ) {
+		$path = substr( $path, 2 );
+	}
+	return $path;
 }
 
 /**
@@ -42,12 +46,16 @@
 		if ( 0 === strpos( $field_name, 'editor' ) ) {
 			$asset_handle .= '-editor';
 		}
+		if ( 0 === strpos( $field_name, 'view' ) ) {
+			$asset_handle .= '-view';
+		}
 		return $asset_handle;
 	}
 
 	$field_mappings = array(
 		'editorScript' => 'editor-script',
 		'script'       => 'script',
+		'viewScript'   => 'view-script',
 		'editorStyle'  => 'editor-style',
 		'style'        => 'style',
 	);
@@ -79,9 +87,11 @@
 	}
 
 	$script_handle     = generate_block_asset_handle( $metadata['name'], $field_name );
-	$script_asset_path = realpath(
-		dirname( $metadata['file'] ) . '/' .
-		substr_replace( $script_path, '.asset.php', - strlen( '.js' ) )
+	$script_asset_path = wp_normalize_path(
+		realpath(
+			dirname( $metadata['file'] ) . '/' .
+			substr_replace( $script_path, '.asset.php', - strlen( '.js' ) )
+		)
 	);
 	if ( ! file_exists( $script_asset_path ) ) {
 		_doing_it_wrong(
@@ -96,18 +106,33 @@
 		);
 		return false;
 	}
-	$script_asset = require $script_asset_path;
-	$result       = wp_register_script(
+	// Path needs to be normalized to work in Windows env.
+	$wpinc_path_norm  = wp_normalize_path( realpath( ABSPATH . WPINC ) );
+	$theme_path_norm  = wp_normalize_path( get_theme_file_path() );
+	$script_path_norm = wp_normalize_path( realpath( dirname( $metadata['file'] ) . '/' . $script_path ) );
+	$is_core_block    = isset( $metadata['file'] ) && 0 === strpos( $metadata['file'], $wpinc_path_norm );
+	$is_theme_block   = 0 === strpos( $script_path_norm, $theme_path_norm );
+
+	$script_uri = plugins_url( $script_path, $metadata['file'] );
+	if ( $is_core_block ) {
+		$script_uri = includes_url( str_replace( $wpinc_path_norm, '', $script_path_norm ) );
+	} elseif ( $is_theme_block ) {
+		$script_uri = get_theme_file_uri( str_replace( $theme_path_norm, '', $script_path_norm ) );
+	}
+
+	$script_asset        = require $script_asset_path;
+	$script_dependencies = isset( $script_asset['dependencies'] ) ? $script_asset['dependencies'] : array();
+	$result              = wp_register_script(
 		$script_handle,
-		plugins_url( $script_path, $metadata['file'] ),
-		$script_asset['dependencies'],
-		$script_asset['version']
+		$script_uri,
+		$script_dependencies,
+		isset( $script_asset['version'] ) ? $script_asset['version'] : false
 	);
 	if ( ! $result ) {
 		return false;
 	}
 
-	if ( ! empty( $metadata['textdomain'] ) ) {
+	if ( ! empty( $metadata['textdomain'] ) && in_array( 'wp-i18n', $script_dependencies, true ) ) {
 		wp_set_script_translations( $script_handle, $metadata['textdomain'] );
 	}
 
@@ -130,7 +155,9 @@
 	if ( empty( $metadata[ $field_name ] ) ) {
 		return false;
 	}
-	$is_core_block = isset( $metadata['file'] ) && 0 === strpos( $metadata['file'], ABSPATH . WPINC );
+	$wpinc_path_norm = wp_normalize_path( realpath( ABSPATH . WPINC ) );
+	$theme_path_norm = wp_normalize_path( get_theme_file_path() );
+	$is_core_block   = isset( $metadata['file'] ) && 0 === strpos( $metadata['file'], $wpinc_path_norm );
 	if ( $is_core_block && ! wp_should_load_separate_core_block_assets() ) {
 		return false;
 	}
@@ -151,6 +178,13 @@
 		$style_uri  = includes_url( 'blocks/' . str_replace( 'core/', '', $metadata['name'] ) . "/style$suffix.css" );
 	}
 
+	$style_path_norm = wp_normalize_path( realpath( dirname( $metadata['file'] ) . '/' . $style_path ) );
+	$is_theme_block  = 0 === strpos( $style_path_norm, $theme_path_norm );
+
+	if ( $is_theme_block ) {
+		$style_uri = get_theme_file_uri( str_replace( $theme_path_norm, '', $style_path_norm ) );
+	}
+
 	$style_handle   = generate_block_asset_handle( $metadata['name'], $field_name );
 	$block_dir      = dirname( $metadata['file'] );
 	$style_file     = realpath( "$block_dir/$style_path" );
@@ -179,12 +213,32 @@
 }
 
 /**
+ * Gets i18n schema for block's metadata read from `block.json` file.
+ *
+ * @since 5.9.0
+ *
+ * @return object The schema for block's metadata.
+ */
+function get_block_metadata_i18n_schema() {
+	static $i18n_block_schema;
+
+	if ( ! isset( $i18n_block_schema ) ) {
+		$i18n_block_schema = wp_json_file_decode( __DIR__ . '/block-i18n.json' );
+	}
+
+	return $i18n_block_schema;
+}
+
+/**
  * Registers a block type from the metadata stored in the `block.json` file.
  *
  * @since 5.5.0
+ * @since 5.7.0 Added support for `textdomain` field and i18n handling for all translatable fields.
+ * @since 5.9.0 Added support for `variations` and `viewScript` fields.
  *
  * @param string $file_or_folder Path to the JSON file with metadata definition for
  *                               the block or path to the folder where the `block.json` file is located.
+ *                               If providing the path to a JSON file, the filename must end with `block.json`.
  * @param array  $args           Optional. Array of block type arguments. Accepts any public property
  *                               of `WP_Block_Type`. See WP_Block_Type::__construct() for information
  *                               on accepted arguments. Default empty array.
@@ -199,11 +253,11 @@
 		return false;
 	}
 
-	$metadata = json_decode( file_get_contents( $metadata_file ), true );
+	$metadata = wp_json_file_decode( $metadata_file, array( 'associative' => true ) );
 	if ( ! is_array( $metadata ) || empty( $metadata['name'] ) ) {
 		return false;
 	}
-	$metadata['file'] = $metadata_file;
+	$metadata['file'] = wp_normalize_path( realpath( $metadata_file ) );
 
 	/**
 	 * Filters the metadata provided for registering a block type.
@@ -228,9 +282,11 @@
 
 	$settings          = array();
 	$property_mappings = array(
+		'apiVersion'      => 'api_version',
 		'title'           => 'title',
 		'category'        => 'category',
 		'parent'          => 'parent',
+		'ancestor'        => 'ancestor',
 		'icon'            => 'icon',
 		'description'     => 'description',
 		'keywords'        => 'keywords',
@@ -239,53 +295,17 @@
 		'usesContext'     => 'uses_context',
 		'supports'        => 'supports',
 		'styles'          => 'styles',
+		'variations'      => 'variations',
 		'example'         => 'example',
-		'apiVersion'      => 'api_version',
 	);
+	$textdomain        = ! empty( $metadata['textdomain'] ) ? $metadata['textdomain'] : null;
+	$i18n_schema       = get_block_metadata_i18n_schema();
 
 	foreach ( $property_mappings as $key => $mapped_key ) {
 		if ( isset( $metadata[ $key ] ) ) {
-			$value = $metadata[ $key ];
-			if ( empty( $metadata['textdomain'] ) ) {
-				$settings[ $mapped_key ] = $value;
-				continue;
-			}
-			$textdomain = $metadata['textdomain'];
-			switch ( $key ) {
-				case 'title':
-				case 'description':
-					// phpcs:ignore WordPress.WP.I18n.LowLevelTranslationFunction,WordPress.WP.I18n.NonSingularStringLiteralText,WordPress.WP.I18n.NonSingularStringLiteralContext,WordPress.WP.I18n.NonSingularStringLiteralDomain
-					$settings[ $mapped_key ] = translate_with_gettext_context( $value, sprintf( 'block %s', $key ), $textdomain );
-					break;
-				case 'keywords':
-					$settings[ $mapped_key ] = array();
-					if ( ! is_array( $value ) ) {
-						continue 2;
-					}
-
-					foreach ( $value as $keyword ) {
-						// phpcs:ignore WordPress.WP.I18n.LowLevelTranslationFunction,WordPress.WP.I18n.NonSingularStringLiteralText,WordPress.WP.I18n.NonSingularStringLiteralDomain
-						$settings[ $mapped_key ][] = translate_with_gettext_context( $keyword, 'block keyword', $textdomain );
-					}
-
-					break;
-				case 'styles':
-					$settings[ $mapped_key ] = array();
-					if ( ! is_array( $value ) ) {
-						continue 2;
-					}
-
-					foreach ( $value as $style ) {
-						if ( ! empty( $style['label'] ) ) {
-							// phpcs:ignore WordPress.WP.I18n.LowLevelTranslationFunction,WordPress.WP.I18n.NonSingularStringLiteralText,WordPress.WP.I18n.NonSingularStringLiteralDomain
-							$style['label'] = translate_with_gettext_context( $style['label'], 'block style label', $textdomain );
-						}
-						$settings[ $mapped_key ][] = $style;
-					}
-
-					break;
-				default:
-					$settings[ $mapped_key ] = $value;
+			$settings[ $mapped_key ] = $metadata[ $key ];
+			if ( $textdomain && isset( $i18n_schema->$key ) ) {
+				$settings[ $mapped_key ] = translate_settings_using_i18n_schema( $i18n_schema->$key, $settings[ $key ], $textdomain );
 			}
 		}
 	}
@@ -304,6 +324,13 @@
 		);
 	}
 
+	if ( ! empty( $metadata['viewScript'] ) ) {
+		$settings['view_script'] = register_block_script_handle(
+			$metadata,
+			'viewScript'
+		);
+	}
+
 	if ( ! empty( $metadata['editorStyle'] ) ) {
 		$settings['editor_style'] = register_block_style_handle(
 			$metadata,
@@ -346,7 +373,7 @@
  * the metadata stored in the `block.json` file.
  *
  * @since 5.0.0
- * @since 5.8.0 First param accepts a path to the `block.json` file.
+ * @since 5.8.0 First parameter now accepts a path to the `block.json` file.
  *
  * @param string|WP_Block_Type $block_type Block type name including namespace, or alternatively
  *                                         a path to the JSON file with metadata definition for the block,
@@ -381,7 +408,7 @@
 }
 
 /**
- * Determine whether a post or content string has blocks.
+ * Determines whether a post or content string has blocks.
  *
  * This test optimizes for performance rather than strict accuracy, detecting
  * the pattern of a block but not validating its structure. For strict accuracy,
@@ -407,7 +434,7 @@
 }
 
 /**
- * Determine whether a $post or a string contains a specific block type.
+ * Determines whether a $post or a string contains a specific block type.
  *
  * This test optimizes for performance rather than strict accuracy, detecting
  * whether the block type exists but not validating its structure and not checking
@@ -569,7 +596,7 @@
  *
  * @since 5.3.1
  *
- * @param WP_Block_Parser_Block $block A single parsed block object.
+ * @param array $block A representative array of a single parsed block object. See WP_Block_Parser_Block.
  * @return string String of rendered HTML.
  */
 function serialize_block( $block ) {
@@ -597,7 +624,7 @@
  *
  * @since 5.3.1
  *
- * @param WP_Block_Parser_Block[] $blocks Parsed block objects.
+ * @param array[] $blocks An array of representative arrays of parsed block objects. See serialize_block().
  * @return string String of rendered HTML.
  */
 function serialize_blocks( $blocks ) {
@@ -726,7 +753,7 @@
 	 *
 	 * @since 5.8.0
 	 *
-	 * @param array $allowed_wrapper_blocks The list of allowed wrapper blocks.
+	 * @param string[] $allowed_wrapper_blocks The list of names of allowed wrapper blocks.
 	 */
 	$allowed_wrapper_blocks = apply_filters( 'excerpt_allowed_wrapper_blocks', $allowed_wrapper_blocks );
 
@@ -740,7 +767,7 @@
 	 *
 	 * @since 5.0.0
 	 *
-	 * @param array $allowed_blocks The list of allowed blocks.
+	 * @param string[] $allowed_blocks The list of names of allowed blocks.
 	 */
 	$allowed_blocks = apply_filters( 'excerpt_allowed_blocks', $allowed_blocks );
 	$blocks         = parse_blocks( $content );
@@ -776,7 +803,7 @@
  * Render inner blocks from the allowed wrapper blocks
  * for generating an excerpt.
  *
- * @since 5.8
+ * @since 5.8.0
  * @access private
  *
  * @param array $parsed_block   The parsed block.
@@ -813,16 +840,19 @@
  */
 function render_block( $parsed_block ) {
 	global $post;
+	$parent_block = null;
 
 	/**
 	 * Allows render_block() to be short-circuited, by returning a non-null value.
 	 *
 	 * @since 5.1.0
+	 * @since 5.9.0 The `$parent_block` parameter was added.
 	 *
-	 * @param string|null $pre_render   The pre-rendered content. Default null.
-	 * @param array       $parsed_block The block being rendered.
+	 * @param string|null   $pre_render   The pre-rendered content. Default null.
+	 * @param array         $parsed_block The block being rendered.
+	 * @param WP_Block|null $parent_block If this is a nested block, a reference to the parent block.
 	 */
-	$pre_render = apply_filters( 'pre_render_block', null, $parsed_block );
+	$pre_render = apply_filters( 'pre_render_block', null, $parsed_block, $parent_block );
 	if ( ! is_null( $pre_render ) ) {
 		return $pre_render;
 	}
@@ -833,11 +863,13 @@
 	 * Filters the block being rendered in render_block(), before it's processed.
 	 *
 	 * @since 5.1.0
+	 * @since 5.9.0 The `$parent_block` parameter was added.
 	 *
-	 * @param array $parsed_block The block being rendered.
-	 * @param array $source_block An un-modified copy of $parsed_block, as it appeared in the source content.
+	 * @param array         $parsed_block The block being rendered.
+	 * @param array         $source_block An un-modified copy of $parsed_block, as it appeared in the source content.
+	 * @param WP_Block|null $parent_block If this is a nested block, a reference to the parent block.
 	 */
-	$parsed_block = apply_filters( 'render_block_data', $parsed_block, $source_block );
+	$parsed_block = apply_filters( 'render_block_data', $parsed_block, $source_block, $parent_block );
 
 	$context = array();
 
@@ -857,11 +889,13 @@
 	 * Filters the default context provided to a rendered block.
 	 *
 	 * @since 5.5.0
+	 * @since 5.9.0 The `$parent_block` parameter was added.
 	 *
-	 * @param array $context      Default context.
-	 * @param array $parsed_block Block being rendered, filtered by `render_block_data`.
+	 * @param array         $context      Default context.
+	 * @param array         $parsed_block Block being rendered, filtered by `render_block_data`.
+	 * @param WP_Block|null $parent_block If this is a nested block, a reference to the parent block.
 	 */
-	$context = apply_filters( 'render_block_context', $context, $parsed_block );
+	$context = apply_filters( 'render_block_context', $context, $parsed_block, $parent_block );
 
 	$block = new WP_Block( $parsed_block, $context );
 
@@ -920,10 +954,9 @@
  * If do_blocks() needs to remove wpautop() from the `the_content` filter, this re-adds it afterwards,
  * for subsequent `the_content` usage.
  *
+ * @since 5.0.0
  * @access private
  *
- * @since 5.0.0
- *
  * @param string $content The post content running through this filter.
  * @return string The unmodified content.
  */
@@ -985,9 +1018,8 @@
  *
  * @param WP_Block_Type $block_type Block type to check for support.
  * @param string        $feature    Name of the feature to check support for.
- * @param mixed         $default    Fallback value for feature support, defaults to false.
- *
- * @return boolean                  Whether or not the feature is supported.
+ * @param mixed         $default    Optional. Fallback value for feature support. Default false.
+ * @return bool Whether the feature is supported.
  */
 function block_has_support( $block_type, $feature, $default = false ) {
 	$block_support = $default;
@@ -1108,15 +1140,36 @@
 			$query['offset']         = ( $per_page * ( $page - 1 ) ) + $offset;
 			$query['posts_per_page'] = $per_page;
 		}
-		if ( ! empty( $block->context['query']['categoryIds'] ) ) {
-			$term_ids              = array_map( 'intval', $block->context['query']['categoryIds'] );
-			$term_ids              = array_filter( $term_ids );
-			$query['category__in'] = $term_ids;
+		// Migrate `categoryIds` and `tagIds` to `tax_query` for backwards compatibility.
+		if ( ! empty( $block->context['query']['categoryIds'] ) || ! empty( $block->context['query']['tagIds'] ) ) {
+			$tax_query = array();
+			if ( ! empty( $block->context['query']['categoryIds'] ) ) {
+				$tax_query[] = array(
+					'taxonomy'         => 'category',
+					'terms'            => array_filter( array_map( 'intval', $block->context['query']['categoryIds'] ) ),
+					'include_children' => false,
+				);
+			}
+			if ( ! empty( $block->context['query']['tagIds'] ) ) {
+				$tax_query[] = array(
+					'taxonomy'         => 'post_tag',
+					'terms'            => array_filter( array_map( 'intval', $block->context['query']['tagIds'] ) ),
+					'include_children' => false,
+				);
+			}
+			$query['tax_query'] = $tax_query;
 		}
-		if ( ! empty( $block->context['query']['tagIds'] ) ) {
-			$term_ids         = array_map( 'intval', $block->context['query']['tagIds'] );
-			$term_ids         = array_filter( $term_ids );
-			$query['tag__in'] = $term_ids;
+		if ( ! empty( $block->context['query']['taxQuery'] ) ) {
+			$query['tax_query'] = array();
+			foreach ( $block->context['query']['taxQuery'] as $taxonomy => $terms ) {
+				if ( is_taxonomy_viewable( $taxonomy ) && ! empty( $terms ) ) {
+					$query['tax_query'][] = array(
+						'taxonomy'         => $taxonomy,
+						'terms'            => array_filter( array_map( 'intval', $terms ) ),
+						'include_children' => false,
+					);
+				}
+			}
 		}
 		if (
 			isset( $block->context['query']['order'] ) &&
@@ -1139,3 +1192,188 @@
 	}
 	return $query;
 }
+
+/**
+ * Helper function that returns the proper pagination arrow HTML for
+ * `QueryPaginationNext` and `QueryPaginationPrevious` blocks based
+ * on the provided `paginationArrow` from `QueryPagination` context.
+ *
+ * It's used in QueryPaginationNext and QueryPaginationPrevious blocks.
+ *
+ * @since 5.9.0
+ *
+ * @param WP_Block $block   Block instance.
+ * @param boolean  $is_next Flag for handling `next/previous` blocks.
+ *
+ * @return string|null The pagination arrow HTML or null if there is none.
+ */
+function get_query_pagination_arrow( $block, $is_next ) {
+	$arrow_map = array(
+		'none'    => '',
+		'arrow'   => array(
+			'next'     => '→',
+			'previous' => '←',
+		),
+		'chevron' => array(
+			'next'     => '»',
+			'previous' => '«',
+		),
+	);
+	if ( ! empty( $block->context['paginationArrow'] ) && array_key_exists( $block->context['paginationArrow'], $arrow_map ) && ! empty( $arrow_map[ $block->context['paginationArrow'] ] ) ) {
+		$pagination_type = $is_next ? 'next' : 'previous';
+		$arrow_attribute = $block->context['paginationArrow'];
+		$arrow           = $arrow_map[ $block->context['paginationArrow'] ][ $pagination_type ];
+		$arrow_classes   = "wp-block-query-pagination-$pagination_type-arrow is-arrow-$arrow_attribute";
+		return "<span class='$arrow_classes'>$arrow</span>";
+	}
+	return null;
+}
+
+/**
+ * Allows multiple block styles.
+ *
+ * @since 5.9.0
+ *
+ * @param array $metadata Metadata for registering a block type.
+ * @return array Metadata for registering a block type.
+ */
+function _wp_multiple_block_styles( $metadata ) {
+	foreach ( array( 'style', 'editorStyle' ) as $key ) {
+		if ( ! empty( $metadata[ $key ] ) && is_array( $metadata[ $key ] ) ) {
+			$default_style = array_shift( $metadata[ $key ] );
+			foreach ( $metadata[ $key ] as $handle ) {
+				$args = array( 'handle' => $handle );
+				if ( 0 === strpos( $handle, 'file:' ) && isset( $metadata['file'] ) ) {
+					$style_path      = remove_block_asset_path_prefix( $handle );
+					$theme_path_norm = wp_normalize_path( get_theme_file_path() );
+					$style_path_norm = wp_normalize_path( realpath( dirname( $metadata['file'] ) . '/' . $style_path ) );
+					$is_theme_block  = isset( $metadata['file'] ) && 0 === strpos( $metadata['file'], $theme_path_norm );
+
+					$style_uri = plugins_url( $style_path, $metadata['file'] );
+
+					if ( $is_theme_block ) {
+						$style_uri = get_theme_file_uri( str_replace( $theme_path_norm, '', $style_path_norm ) );
+					}
+
+					$args = array(
+						'handle' => sanitize_key( "{$metadata['name']}-{$style_path}" ),
+						'src'    => $style_uri,
+					);
+				}
+
+				wp_enqueue_block_style( $metadata['name'], $args );
+			}
+
+			// Only return the 1st item in the array.
+			$metadata[ $key ] = $default_style;
+		}
+	}
+	return $metadata;
+}
+add_filter( 'block_type_metadata', '_wp_multiple_block_styles' );
+
+/**
+ * Helper function that constructs a comment query vars array from the passed
+ * block properties.
+ *
+ * It's used with the Comment Query Loop inner blocks.
+ *
+ * @since 6.0.0
+ *
+ * @param WP_Block $block Block instance.
+ *
+ * @return array Returns the comment query parameters to use with the
+ *               WP_Comment_Query constructor.
+ */
+function build_comment_query_vars_from_block( $block ) {
+
+	$comment_args = array(
+		'orderby'       => 'comment_date_gmt',
+		'order'         => 'ASC',
+		'status'        => 'approve',
+		'no_found_rows' => false,
+	);
+
+	if ( is_user_logged_in() ) {
+		$comment_args['include_unapproved'] = array( get_current_user_id() );
+	} else {
+		$unapproved_email = wp_get_unapproved_comment_author_email();
+
+		if ( $unapproved_email ) {
+			$comment_args['include_unapproved'] = array( $unapproved_email );
+		}
+	}
+
+	if ( ! empty( $block->context['postId'] ) ) {
+		$comment_args['post_id'] = (int) $block->context['postId'];
+	}
+
+	if ( get_option( 'thread_comments' ) ) {
+		$comment_args['hierarchical'] = 'threaded';
+	} else {
+		$comment_args['hierarchical'] = false;
+	}
+
+	if ( get_option( 'page_comments' ) === '1' || get_option( 'page_comments' ) === true ) {
+		$per_page     = get_option( 'comments_per_page' );
+		$default_page = get_option( 'default_comments_page' );
+		if ( $per_page > 0 ) {
+			$comment_args['number'] = $per_page;
+
+			$page = (int) get_query_var( 'cpage' );
+			if ( $page ) {
+				$comment_args['paged'] = $page;
+			} elseif ( 'oldest' === $default_page ) {
+				$comment_args['paged'] = 1;
+			} elseif ( 'newest' === $default_page ) {
+				$max_num_pages = (int) ( new WP_Comment_Query( $comment_args ) )->max_num_pages;
+				if ( 0 !== $max_num_pages ) {
+					$comment_args['paged'] = $max_num_pages;
+				}
+			}
+			// Set the `cpage` query var to ensure the previous and next pagination links are correct
+			// when inheriting the Discussion Settings.
+			if ( 0 === $page && isset( $comment_args['paged'] ) && $comment_args['paged'] > 0 ) {
+				set_query_var( 'cpage', $comment_args['paged'] );
+			}
+		}
+	}
+
+	return $comment_args;
+}
+
+/**
+ * Helper function that returns the proper pagination arrow HTML for
+ * `CommentsPaginationNext` and `CommentsPaginationPrevious` blocks based on the
+ * provided `paginationArrow` from `CommentsPagination` context.
+ *
+ * It's used in CommentsPaginationNext and CommentsPaginationPrevious blocks.
+ *
+ * @since 6.0.0
+ *
+ * @param WP_Block $block           Block instance.
+ * @param string   $pagination_type Type of the arrow we will be rendering.
+ *                                  Default 'next'. Accepts 'next' or 'previous'.
+ *
+ * @return string|null The pagination arrow HTML or null if there is none.
+ */
+function get_comments_pagination_arrow( $block, $pagination_type = 'next' ) {
+	$arrow_map = array(
+		'none'    => '',
+		'arrow'   => array(
+			'next'     => '→',
+			'previous' => '←',
+		),
+		'chevron' => array(
+			'next'     => '»',
+			'previous' => '«',
+		),
+	);
+	if ( ! empty( $block->context['comments/paginationArrow'] ) && ! empty( $arrow_map[ $block->context['comments/paginationArrow'] ][ $pagination_type ] ) ) {
+		$arrow_attribute = $block->context['comments/paginationArrow'];
+		$arrow           = $arrow_map[ $block->context['comments/paginationArrow'] ][ $pagination_type ];
+		$arrow_classes   = "wp-block-comments-pagination-$pagination_type-arrow is-arrow-$arrow_attribute";
+		return "<span class='$arrow_classes'>$arrow</span>";
+	}
+	return null;
+}