Ticket #42457: 42457.0.diff

src/wp-admin/customize.php

@@ -42 +42 @@
                 get_post_time( 'G', true, $changeset_post ) < time()
         );
         if ( $missed_schedule ) {
-                wp_publish_post( $changeset_post->ID );
+                /*
+                 * Note that cron is spawned here instead of just calling `wp_publish_post( $changeset_post->ID )`.
+                 * The reason for this is that WP_Customize_Manager is not instantiated for customize.php with
+                 * the `settings_previewed=false` argument. Because of this, settings cannot by reliably saved just
+                 * since some settings will short-circuit if they detect that the current value is the same as
+                 * the value to be saved. This is particularly true for options due to logic in the update_option()
+                 * function. For more, See #39221. So by spawning cron, then the changeset will get published in
+                 * the request to `wp-cron.php` where WP_Customize_Manager will get instantiated with
+                 * `settings_previewed=false` according to `_wp_customize_publish_changeset()`.
+                 */
+                spawn_cron();
+
                 wp_die(
                         '<h1>' . __( 'Your scheduled changes just published' ) . '</h1>' .
                         '<p><a href="' . esc_url( remove_query_arg( 'changeset_uuid' ) ) . '">' . __( 'Customize New Changes' ) . '</a></p>',