Editor: Add emoji reactions as a comment type for Notes

src/wp-admin/includes/class-wp-comments-list-table.php

@@ -105,7 +105,7 @@ public function prepare_items() {
 
 		$comment_type = '';
 
-		if ( ! empty( $_REQUEST['comment_type'] ) && 'note' !== $_REQUEST['comment_type'] ) {
+		if ( ! empty( $_REQUEST['comment_type'] ) && ! in_array( $_REQUEST['comment_type'], wp_get_internal_comment_types(), true ) ) {
 			$comment_type = $_REQUEST['comment_type'];
 		}
 
@@ -155,7 +155,7 @@ public function prepare_items() {
 			'number'                    => $number,
 			'post_id'                   => $post_id,
 			'type'                      => $comment_type,
-			'type__not_in'              => array( 'note' ),
+			'type__not_in'              => wp_get_internal_comment_types(),
 			'orderby'                   => $orderby,
 			'order'                     => $order,
 			'post_type'                 => $post_type,

src/wp-admin/includes/comment.php

@@ -158,7 +158,16 @@ function get_pending_comments_num( $post_id ) {
 	$post_id_array = array_map( 'intval', $post_id_array );
 	$post_id_in    = "'" . implode( "', '", $post_id_array ) . "'";
 
-	$pending = $wpdb->get_results( "SELECT comment_post_ID, COUNT(comment_ID) as num_comments FROM $wpdb->comments WHERE comment_post_ID IN ( $post_id_in ) AND comment_approved = '0' AND comment_type != 'note' GROUP BY comment_post_ID", ARRAY_A );
+	$internal_comment_types = wp_get_internal_comment_types();
+	$type_placeholders      = implode( ', ', array_fill( 0, count( $internal_comment_types ), '%s' ) );
+	$pending                = $wpdb->get_results(
+		$wpdb->prepare(
+			// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
+			"SELECT comment_post_ID, COUNT(comment_ID) as num_comments FROM $wpdb->comments WHERE comment_post_ID IN ( $post_id_in ) AND comment_approved = '0' AND comment_type NOT IN ( $type_placeholders ) GROUP BY comment_post_ID",
+			$internal_comment_types
+		),
+		ARRAY_A
+	);
 
 	if ( $single ) {
 		if ( empty( $pending ) ) {

src/wp-includes/comment.php

@@ -294,6 +294,29 @@ function get_comment_statuses() {
 	return $status;
 }
 
+/**
+ * Retrieves the list of internal comment types.
+ *
+ * Internal comment types are used by core features (such as block notes
+ * and emoji reactions) and are not user-authored discussion comments.
+ * They should typically be excluded from front-end and admin comment
+ * listings, counts, and similar contexts that target user discussion.
+ *
+ * @since 7.0.0
+ *
+ * @return string[] List of internal comment type slugs.
+ */
+function wp_get_internal_comment_types(): array {
+	/**
+	 * Filters the list of internal comment types.
+	 *
+	 * @since 7.0.0
+	 *
+	 * @param string[] $types List of internal comment type slugs.
+	 */
+	return (array) apply_filters( 'wp_internal_comment_types', array( 'note', 'reaction' ) );
+}
+
 /**
  * Gets the default comment status for a post type.
  *
@@ -2876,7 +2899,14 @@ function wp_update_comment_count_now( $post_id ) {
 	$new = apply_filters( 'pre_wp_update_comment_count_now', null, $old, $post_id );
 
 	if ( is_null( $new ) ) {
-		$new = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_approved = '1' AND comment_type != 'note'", $post_id ) );
+		$internal_comment_types = wp_get_internal_comment_types();
+		$type_placeholders      = implode( ', ', array_fill( 0, count( $internal_comment_types ), '%s' ) );
+		$new                    = (int) $wpdb->get_var(
+			$wpdb->prepare(
+				"SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_approved = '1' AND comment_type NOT IN ( $type_placeholders )", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
+				array_merge( array( $post_id ), $internal_comment_types )
+			)
+		);
 	} else {
 		$new = (int) $new;
 	}

src/wp-includes/link-template.php

@@ -4349,10 +4349,12 @@ function is_avatar_comment_type( $comment_type ) {
 	 * @since 3.0.0
 	 *
 	 * @since 6.9.0 The 'note' comment type was added.
+	 * @since 7.0.0 The 'reaction' comment type was added.
 	 *
-	 * @param array $types An array of content types. Default contains 'comment' and 'note'.
+	 * @param array $types An array of content types. Default contains 'comment' and the
+	 *                     internal comment types returned by wp_get_internal_comment_types().
 	 */
-	$allowed_comment_types = apply_filters( 'get_avatar_comment_types', array( 'comment', 'note' ) );
+	$allowed_comment_types = apply_filters( 'get_avatar_comment_types', array_merge( array( 'comment' ), wp_get_internal_comment_types() ) );
 
 	return in_array( $comment_type, (array) $allowed_comment_types, true );
 }

src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php

@@ -123,7 +123,7 @@ public function register_routes() {
 	 * @return true|WP_Error True if the request has read access, error object otherwise.
 	 */
 	public function get_items_permissions_check( $request ) {
-		$is_note          = 'note' === $request['type'];
+		$is_note          = in_array( $request['type'], wp_get_internal_comment_types(), true );
 		$is_edit_context  = 'edit' === $request['context'];
 		$protected_params = array( 'author', 'author_exclude', 'author_email', 'type', 'status' );
 		$forbidden_params = array();
@@ -437,8 +437,8 @@ public function get_item_permissions_check( $request ) {
 			return $comment;
 		}
 
-		// Re-map edit context capabilities when requesting `note` type.
-		$edit_cap = 'note' === $comment->comment_type ? array( 'edit_comment', $comment->comment_ID ) : array( 'moderate_comments' );
+		// Re-map edit context capabilities when requesting `note` or `reaction` type.
+		$edit_cap = in_array( $comment->comment_type, wp_get_internal_comment_types(), true ) ? array( 'edit_comment', $comment->comment_ID ) : array( 'moderate_comments' );
 		if ( ! empty( $request['context'] ) && 'edit' === $request['context'] && ! current_user_can( ...$edit_cap ) ) {
 			return new WP_Error(
 				'rest_forbidden_context',
@@ -497,7 +497,7 @@ public function get_item( $request ) {
 	 * @return true|WP_Error True if the request has access to create items, error object otherwise.
 	 */
 	public function create_item_permissions_check( $request ) {
-		$is_note = ! empty( $request['type'] ) && 'note' === $request['type'];
+		$is_note = ! empty( $request['type'] ) && in_array( $request['type'], wp_get_internal_comment_types(), true );
 
 		if ( ! is_user_logged_in() && $is_note ) {
 			return new WP_Error(
@@ -657,14 +657,65 @@ public function create_item( $request ) {
 		}
 
 		// Do not allow comments to be created with a non-core type.
-		if ( ! empty( $request['type'] ) && ! in_array( $request['type'], array( 'comment', 'note' ), true ) ) {
+		if ( ! empty( $request['type'] ) && ! in_array( $request['type'], array_merge( array( 'comment' ), wp_get_internal_comment_types() ), true ) ) {
 			return new WP_Error(
 				'rest_invalid_comment_type',
 				__( 'Cannot create a comment with that type.' ),
 				array( 'status' => 400 )
 			);
 		}
 
+		// Validate reaction-specific constraints.
+		if ( ! empty( $request['type'] ) && 'reaction' === $request['type'] ) {
+			$valid_emojis = array( 'heart', 'celebration', 'smile', 'eyes', 'rocket' );
+
+			// Reaction content must be a valid emoji slug.
+			if ( empty( $request['content'] ) || ! in_array( $request['content'], $valid_emojis, true ) ) {
+				return new WP_Error(
+					'rest_reaction_invalid_emoji',
+					__( 'Reaction content must be a valid emoji slug.' ),
+					array( 'status' => 400 )
+				);
+			}
+
+			// Reaction parent must exist and be a note.
+			if ( empty( $request['parent'] ) ) {
+				return new WP_Error(
+					'rest_reaction_parent_required',
+					__( 'Reactions must have a parent note.' ),
+					array( 'status' => 400 )
+				);
+			}
+
+			$parent_comment = get_comment( $request['parent'] );
+			if ( ! $parent_comment || 'note' !== $parent_comment->comment_type ) {
+				return new WP_Error(
+					'rest_reaction_invalid_parent',
+					__( 'Reactions can only be added to notes.' ),
+					array( 'status' => 400 )
+				);
+			}
+
+			// Enforce uniqueness: one emoji per user per note.
+			$existing = get_comments(
+				array(
+					'comment_type'   => 'reaction',
+					'comment_parent' => $request['parent'],
+					'user_id'        => get_current_user_id(),
+					'search'         => $request['content'],
+					'count'          => true,
+				)
+			);
+
+			if ( $existing > 0 ) {
+				return new WP_Error(
+					'rest_reaction_duplicate',
+					__( 'You have already added this reaction.' ),
+					array( 'status' => 409 )
+				);
+			}
+		}
+
 		$prepared_comment = $this->prepare_item_for_database( $request );
 		if ( is_wp_error( $prepared_comment ) ) {
 			return $prepared_comment;
@@ -743,9 +794,9 @@ public function create_item( $request ) {
 			);
 		}
 
-		// Don't check for duplicates or flooding for notes.
+		// Don't check for duplicates or flooding for notes or reactions.
 		$prepared_comment['comment_approved'] =
-			'note' === $prepared_comment['comment_type'] ?
+			in_array( $prepared_comment['comment_type'], wp_get_internal_comment_types(), true ) ?
 			'1' :
 			wp_allow_comment( $prepared_comment, true );
 
@@ -1305,7 +1356,7 @@ protected function prepare_links( $comment ) {
 		}
 
 		// Embedding children for notes requires `type` and `status` inheritance.
-		if ( isset( $links['children'] ) && 'note' === $comment->comment_type ) {
+		if ( isset( $links['children'] ) && in_array( $comment->comment_type, wp_get_internal_comment_types(), true ) ) {
 			$args = array(
 				'parent' => $comment->comment_ID,
 				'type'   => $comment->comment_type,
@@ -1919,7 +1970,7 @@ protected function check_read_post_permission( $post, $request ) {
 	 * @return bool Whether the comment can be read.
 	 */
 	protected function check_read_permission( $comment, $request ) {
-		if ( 'note' !== $comment->comment_type && ! empty( $comment->comment_post_ID ) ) {
+		if ( ! in_array( $comment->comment_type, wp_get_internal_comment_types(), true ) && ! empty( $comment->comment_post_ID ) ) {
 			$post = get_post( $comment->comment_post_ID );
 			if ( $post ) {
 				if ( $this->check_read_post_permission( $post, $request ) && 1 === (int) $comment->comment_approved ) {
@@ -2034,6 +2085,11 @@ protected function check_is_comment_content_allowed( $prepared_comment ) {
 			return true;
 		}
 
+		// Reactions always have content (the emoji slug), so allow them.
+		if ( isset( $check['comment_type'] ) && 'reaction' === $check['comment_type'] ) {
+			return true;
+		}
+
 		/*
 		 * Do not allow a comment to be created with missing or empty
 		 * comment_content. See wp_handle_comment_submission().

tests/phpunit/tests/comment/wpUpdateCommentCountNow.php

@@ -78,6 +78,20 @@ public function test_only_approved_regular_comments_are_counted() {
 				'comment_approved' => 1,
 			)
 		);
+		self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => $post_id,
+				'comment_type'     => 'reaction',
+				'comment_approved' => 0,
+			)
+		);
+		self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => $post_id,
+				'comment_type'     => 'reaction',
+				'comment_approved' => 1,
+			)
+		);
 
 		$this->assertTrue( wp_update_comment_count_now( $post_id ) );
 		$this->assertSame( '1', get_comments_number( $post_id ) );