Notes unexpected do not notify post author (unlike comments)

src/wp-includes/comment.php

@@ -2447,14 +2447,43 @@ function wp_new_comment_notify_postauthor( $comment_id ) {
 		return false;
 	}
 
-	// Only send notifications for approved comments.
-	if ( ! isset( $comment->comment_approved ) || '1' !== $comment->comment_approved ) {
-		return false;
+	// Send notifications for approved comments and all notes.
+	if (
+		! isset( $comment->comment_approved ) ||
+		( '1' !== $comment->comment_approved && 'note' !== $comment->comment_type ) ) {
+			return false;
 	}
 
 	return wp_notify_postauthor( $comment_id );
 }
 
+/**
+ * Send a notification to the post author when a new note is added via the REST API.
+ *
+ * @since 6.9.0
+ *
+ * @param WP_Comment $comment The comment object.
+ */
+function wp_new_comment_via_rest_notify_postauthor( $comment ) {
+	if ( 'note' === $comment->comment_type ) {
+		// Queue up the email notification as a cron callback. The second parameter ensures each callback is executed.
+		wp_schedule_single_event( time(), 'wp_new_comment_via_rest_notify_postauthor', array( $comment->comment_ID, time() ) );
+	}
+}
+
+/**
+ * Cron callback to send an author email notifcation, keeping the action asynchronous.
+ */
+function wp_new_comment_via_rest_notify_postauthor_cron( $comment_id ) {
+	$comment = get_comment( $comment_id );
+	if ( $comment ) {
+		wp_new_comment_notify_postauthor( $comment_id );
+	}
+}
+
+// Add a custom hook for the note notification cron job.
+add_action( 'wp_new_comment_via_rest_notify_postauthor', 'wp_new_comment_via_rest_notify_postauthor_cron' );
+
 /**
  * Sets the status of a comment.
  *

src/wp-includes/default-filters.php

@@ -522,6 +522,7 @@
 // Email notifications.
 add_action( 'comment_post', 'wp_new_comment_notify_moderator' );
 add_action( 'comment_post', 'wp_new_comment_notify_postauthor' );
+add_action( 'rest_insert_comment', 'wp_new_comment_via_rest_notify_postauthor' );
 add_action( 'after_password_reset', 'wp_password_change_notification' );
 add_action( 'register_new_user', 'wp_send_new_user_notifications' );
 add_action( 'edit_user_created_user', 'wp_send_new_user_notifications', 10, 2 );

src/wp-includes/pluggable.php

@@ -1746,6 +1746,11 @@ function wp_notify_postauthor( $comment_id, $deprecated = null ) {
 			return false;
 		}
 
+		// Skip notifications for empty notes.
+		if ( 'note' === $comment->comment_type && empty( $comment->comment_content ) ) {
+			return false;
+		}
+
 		$post   = get_post( $comment->comment_post_ID );
 		$author = get_userdata( $post->post_author );
 
@@ -1894,6 +1899,20 @@ function wp_notify_postauthor( $comment_id, $deprecated = null ) {
 					$subject = sprintf( __( '[%1$s] Pingback: "%2$s"' ), $blogname, $post->post_title );
 					break;
 
+				case 'note':
+					/* translators: %s: Post title. */
+					$notify_message = sprintf( __( 'New note on your post "%s"' ), $post->post_title ) . "\r\n";
+					/* translators: 1: Note author's name, 2: Note author's IP address, 3: Note author's hostname. */
+					$notify_message .= sprintf( __( 'Author: %1$s (IP address: %2$s, %3$s)' ), $comment->comment_author, $comment->comment_author_IP, $comment_author_domain ) . "\r\n";
+					/* translators: %s: Note author email. */
+					$notify_message .= sprintf( __( 'Email: %s' ), $comment->comment_author_email ) . "\r\n";
+					/* translators: %s: Note text. */
+					$notify_message .= sprintf( __( 'Note: %s' ), "\r\n" . $comment_content ) . "\r\n\r\n";
+					$notify_message .= __( 'You can see all notes on this post here:' ) . "\r\n";
+					/* translators: Note notification email subject. 1: Site title, 2: Post title. */
+					$subject = sprintf( __( '[%1$s] Note: "%2$s"' ), $blogname, $post->post_title );
+					break;
+
 				default: // Comments.
 					/* translators: %s: Post title. */
 					$notify_message = sprintf( __( 'New comment on your post "%s"' ), $post->post_title ) . "\r\n";
@@ -1917,11 +1936,15 @@ function wp_notify_postauthor( $comment_id, $deprecated = null ) {
 					break;
 			}
 
-			$notify_message .= get_permalink( $comment->comment_post_ID ) . "#comments\r\n\r\n";
 			/* translators: %s: Comment URL. */
-			$notify_message .= sprintf( __( 'Permalink: %s' ), get_comment_link( $comment ) ) . "\r\n";
+			if ( 'note' === $comment->comment_type ) {
+				$notify_message .= get_edit_post_link( $comment->comment_post_ID, 'url' ) . "\r\n";
+			} else {
+				$notify_message .= get_permalink( $comment->comment_post_ID ) . "#comments\r\n\r\n";
+				$notify_message .= sprintf( __( 'Permalink: %s' ), get_comment_link( $comment ) ) . "\r\n";
+			}
 
-			if ( user_can( $post->post_author, 'edit_comment', $comment->comment_ID ) ) {
+			if ( 'note' !== $comment->comment_type && user_can( $post->post_author, 'edit_comment', $comment->comment_ID ) ) {
 				if ( EMPTY_TRASH_DAYS ) {
 					/* translators: Comment moderation. %s: Comment action URL. */
 					$notify_message .= sprintf( __( 'Trash it: %s' ), admin_url( "comment.php?action=trash&c={$comment->comment_ID}#wpbody-content" ) ) . "\r\n";