Fix waiting list check when max limit is 0 meaning it has no limit.

includes/core/classes/class-rsvp-setup.php

@@ -52,6 +52,8 @@ protected function __construct() {
 	 */
 	protected function setup_hooks(): void {
 		add_action( 'init', array( $this, 'register_taxonomy' ) );
+		add_action( 'wp_after_insert_post', array( $this, 'maybe_process_waiting_list' ) );
+
 		add_filter( 'get_comments_number', array( $this, 'adjust_comments_number' ), 10, 2 );
 	}
 
@@ -101,4 +103,25 @@ public function adjust_comments_number( int $comments_number, int $post_id ): in
 
 		return $comment_count['approved'];
 	}
+
+	/**
+	 * Process the waiting list for an event after it has been saved.
+	 *
+	 * Checks if the saved post is an event and not an autosave,
+	 * then processes any waiting list entries if applicable.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @param int $post_id The ID of the post being saved.
+	 * @return void
+	 */
+	public function maybe_process_waiting_list( int $post_id ): void {
+		if ( Event::POST_TYPE !== get_post_type( $post_id ) ) {
+			return;
+		}
+
+		$rsvp = new Rsvp( $post_id );
+
+		$rsvp->check_waiting_list();
+	}
 }

includes/core/classes/class-rsvp.php

@@ -300,19 +300,28 @@ public function save( int $user_id, string $status, int $anonymous = 0, int $gue
 	 * @return int The number of responses from the waiting list that were moved to attending.
 	 */
 	public function check_waiting_list(): int {
-		$responses = $this->responses();
-		$i         = 0;
+		$responses          = $this->responses();
+		$attending_count    = intval( $responses['attending']['count'] );
+		$waiting_list_count = intval( $responses['waiting_list']['count'] );
+		$i                  = 0;
 
 		if (
-			intval( $responses['attending']['count'] ) < $this->max_attendance_limit
-			&& intval( $responses['waiting_list']['count'] )
+			$waiting_list_count &&
+			(
+				empty( $this->max_attendance_limit ) ||
+				$attending_count < $this->max_attendance_limit
+			)
 		) {
 			$waiting_list = $responses['waiting_list']['records'];
 
 			// People who are longest on the waiting_list should be added first.
 			usort( $waiting_list, array( $this, 'sort_by_timestamp' ) );
 
-			$total = $this->max_attendance_limit - intval( $responses['attending']['count'] );
+			if ( ! empty( $this->max_attendance_limit ) ) {
+				$total = $this->max_attendance_limit - intval( $responses['attending']['count'] );
+			} else {
+				$total = $waiting_list_count;
+			}
 
 			while ( $i < $total ) {
 				// Check that we have enough on the waiting_list to run this.
@@ -321,6 +330,7 @@ public function check_waiting_list(): int {
 				}
 
 				$response = $waiting_list[ $i ];
+
 				$this->save( $response['id'], 'attending', $response['anonymous'] );
 				++$i;
 			}

test/unit/php/includes/core/classes/class-test-rsvp-setup.php

@@ -36,6 +36,12 @@ public function test_setup_hooks(): void {
 				'priority' => 10,
 				'callback' => array( $instance, 'register_taxonomy' ),
 			),
+			array(
+				'type'     => 'action',
+				'name'     => 'wp_after_insert_post',
+				'priority' => 10,
+				'callback' => array( $instance, 'maybe_process_waiting_list' ),
+			),
 			array(
 				'type'     => 'filter',
 				'name'     => 'get_comments_number',