Comments: Introduce a register_comment_type() API

src/wp-includes/class-wp-comment-type.php

@@ -0,0 +1,225 @@
+<?php
+/**
+ * Comment API: WP_Comment_Type class
+ *
+ * @package WordPress
+ * @subpackage Comments
+ * @since 7.3.0
+ */
+
+/**
+ * Core class used for interacting with comment types.
+ *
+ * @since 7.3.0
+ *
+ * @see register_comment_type()
+ */
+#[AllowDynamicProperties]
+final class WP_Comment_Type {
+	/**
+	 * Comment type key.
+	 *
+	 * @since 7.3.0
+	 * @var string
+	 */
+	public $name;
+
+	/**
+	 * Name of the comment type. Usually plural.
+	 *
+	 * @since 7.3.0
+	 * @var string
+	 */
+	public $label;
+
+	/**
+	 * Labels object for this comment type.
+	 *
+	 * If not set, the default comment labels are used.
+	 *
+	 * @see get_comment_type_labels()
+	 *
+	 * @since 7.3.0
+	 * @var stdClass
+	 */
+	public $labels;
+
+	/**
+	 * Default labels.
+	 *
+	 * @since 7.3.0
+	 * @var (string|null)[][] $default_labels
+	 */
+	protected static $default_labels = array();
+
+	/**
+	 * A short descriptive summary of what the comment type is for.
+	 *
+	 * @since 7.3.0
+	 * @var string
+	 */
+	public $description = '';
+
+	/**
+	 * Whether a comment type is intended for use publicly either via the admin interface or by front-end users.
+	 *
+	 * Core does not currently act on this property.
+	 *
+	 * Default true.
+	 *
+	 * @since 7.3.0
+	 * @var bool
+	 */
+	public $public = true;
+
+	/**
+	 * Whether the comment type is for internal use only.
+	 *
+	 * Internal types are meant to be excluded from comment queries and counts by
+	 * default. Core does not currently act on this property.
+	 *
+	 * Default false.
+	 *
+	 * @since 7.3.0
+	 * @var bool
+	 */
+	public $internal = false;
+
+	/**
+	 * Whether this comment type is a native or "built-in" comment type.
+	 *
+	 * Default false.
+	 *
+	 * @since 7.3.0
+	 * @var bool
+	 */
+	public $_builtin = false;
+
+	/**
+	 * Whether the comment type is hierarchical.
+	 *
+	 * Always false. Read by _get_custom_object_labels() to pick default labels.
+	 *
+	 * @since 7.3.0
+	 * @var bool
+	 */
+	public $hierarchical = false;
+
+	/**
+	 * Constructor.
+	 *
+	 * See the register_comment_type() function for accepted arguments for `$args`.
+	 *
+	 * Will populate object properties from the provided arguments and assign other
+	 * default properties based on that information.
+	 *
+	 * @since 7.3.0
+	 *
+	 * @see register_comment_type()
+	 *
+	 * @param string                      $comment_type Comment type key.
+	 * @param array<string, mixed>|string $args         Optional. Array or string of arguments for registering
+	 *                                                  a comment type. Default empty array.
+	 */
+	public function __construct( $comment_type, $args = array() ) {
+		$this->name = $comment_type;
+
+		$this->set_props( $args );
+	}
+
+	/**
+	 * Sets comment type properties.
+	 *
+	 * See the register_comment_type() function for accepted arguments for `$args`.
+	 *
+	 * @since 7.3.0
+	 *
+	 * @param array<string, mixed>|string $args Array or string of arguments for registering a comment type.
+	 */
+	public function set_props( $args ): void {
+		$args = wp_parse_args( $args );
+
+		/**
+		 * Filters the arguments for registering a comment type.
+		 *
+		 * @since 7.3.0
+		 *
+		 * @param array  $args         Array of arguments for registering a comment type.
+		 *                             See the register_comment_type() function for accepted arguments.
+		 * @param string $comment_type Comment type key.
+		 */
+		$args = apply_filters( 'register_comment_type_args', $args, $this->name );
+
+		$comment_type = $this->name;
+
+		/**
+		 * Filters the arguments for registering a specific comment type.
+		 *
+		 * The dynamic portion of the filter name, `$comment_type`, refers to the comment type key.
+		 *
+		 * Possible hook names include:
+		 *
+		 *  - `register_comment_comment_type_args`
+		 *  - `register_pingback_comment_type_args`
+		 *
+		 * @since 7.3.0
+		 *
+		 * @param array  $args         Array of arguments for registering a comment type.
+		 *                             See the register_comment_type() function for accepted arguments.
+		 * @param string $comment_type Comment type key.
+		 */
+		$args = apply_filters( "register_{$comment_type}_comment_type_args", $args, $this->name );
+
+		// No 'label' default, so get_comment_type_labels() can fall back to the default name.
+		$defaults = array(
+			'labels'      => array(),
+			'description' => '',
+			'public'      => true,
+			'internal'    => false,
+			'_builtin'    => false,
+		);
+
+		$args = array_merge( $defaults, $args );
+
+		$args['name'] = $this->name;
+
+		// The hierarchical label slots are null, so a true value would null every default label.
+		$args['hierarchical'] = false;
+
+		foreach ( $args as $property_name => $property_value ) {
+			$this->$property_name = $property_value;
+		}
+
+		$this->labels = get_comment_type_labels( $this );
+		$this->label  = $this->labels->name;
+	}
+
+	/**
+	 * Returns the default labels for comment types.
+	 *
+	 * @since 7.3.0
+	 *
+	 * @return (string|null)[][] The default labels for comment types.
+	 */
+	public static function get_default_labels() {
+		if ( ! empty( self::$default_labels ) ) {
+			return self::$default_labels;
+		}
+
+		self::$default_labels = array(
+			'name'          => array( _x( 'Comments', 'comment type general name' ), null ),
+			'singular_name' => array( _x( 'Comment', 'comment type singular name' ), null ),
+		);
+
+		return self::$default_labels;
+	}
+
+	/**
+	 * Resets the cache for the default labels.
+	 *
+	 * @since 7.3.0
+	 */
+	public static function reset_default_labels(): void {
+		self::$default_labels = array();
+	}
+}

src/wp-includes/comment-template.php

@@ -1195,12 +1195,16 @@ function get_comment_type( $comment_id = 0 ) {
  * Displays the comment type of the current comment.
  *
  * @since 0.71
+ * @since 7.3.0 The default output for a registered non-built-in comment type
+ *              falls back to the type's singular name label.
  *
  * @param string|false $comment_text   Optional. String to display for comment type. Default false.
  * @param string|false $trackback_text Optional. String to display for trackback type. Default false.
  * @param string|false $pingback_text  Optional. String to display for pingback type. Default false.
  */
 function comment_type( $comment_text = false, $trackback_text = false, $pingback_text = false ) {
+	$comment_text_overridden = ( false !== $comment_text );
+
 	if ( false === $comment_text ) {
 		$comment_text = _x( 'Comment', 'noun' );
 	}
@@ -1219,7 +1223,14 @@ function comment_type( $comment_text = false, $trackback_text = false, $pingback
 			echo $pingback_text;
 			break;
 		default:
-			echo $comment_text;
+			// Registered non-built-in types fall back to their singular label.
+			$comment_type_object = $comment_text_overridden ? null : get_comment_type_object( $type );
+
+			if ( $comment_type_object && ! $comment_type_object->_builtin && is_string( $comment_type_object->labels->singular_name ?? null ) ) {
+				echo esc_html( $comment_type_object->labels->singular_name );
+			} else {
+				echo $comment_text;
+			}
 	}
 }