WordPress at a glance
function is not described

_transition_post_status() WP 2.3.0

Hook for managing future post transitions to published.

This is an internal function for using it by WP core itself. It's not recommended to use this function in your code.

Hooks from the function
Return

null. Null. Nothing.

Usage

_transition_post_status( $new_status, $old_status, $post );
$new_status(string) (required)
New post status.
$old_status(string) (required)
Previous post status.
$post(WP_Post) (required)
Post object.

Notes

  • See: wp_clear_scheduled_hook()
  • Global. wpdb. $wpdb WordPress database abstraction object.

Changelog

Since 2.3.0 Introduced.

Code of _transition_post_status() WP 5.7.1

<?php
function _transition_post_status( $new_status, $old_status, $post ) {
	global $wpdb;

	if ( 'publish' !== $old_status && 'publish' === $new_status ) {
		// Reset GUID if transitioning to publish and it is empty.
		if ( '' === get_the_guid( $post->ID ) ) {
			$wpdb->update( $wpdb->posts, array( 'guid' => get_permalink( $post->ID ) ), array( 'ID' => $post->ID ) );
		}

		/**
		 * Fires when a post's status is transitioned from private to published.
		 *
		 * @since 1.5.0
		 * @deprecated 2.3.0 Use {@see 'private_to_publish'} instead.
		 *
		 * @param int $post_id Post ID.
		 */
		do_action_deprecated( 'private_to_published', array( $post->ID ), '2.3.0', 'private_to_publish' );
	}

	// If published posts changed clear the lastpostmodified cache.
	if ( 'publish' === $new_status || 'publish' === $old_status ) {
		foreach ( array( 'server', 'gmt', 'blog' ) as $timezone ) {
			wp_cache_delete( "lastpostmodified:$timezone", 'timeinfo' );
			wp_cache_delete( "lastpostdate:$timezone", 'timeinfo' );
			wp_cache_delete( "lastpostdate:$timezone:{$post->post_type}", 'timeinfo' );
		}
	}

	if ( $new_status !== $old_status ) {
		wp_cache_delete( _count_posts_cache_key( $post->post_type ), 'counts' );
		wp_cache_delete( _count_posts_cache_key( $post->post_type, 'readable' ), 'counts' );
	}

	// Always clears the hook in case the post status bounced from future to draft.
	wp_clear_scheduled_hook( 'publish_future_post', array( $post->ID ) );
}