Source

File: wp-includes/post.php

function wp_publish_post( $post ) {
	global $wpdb;

	$post = get_post( $post );
	if ( ! $post ) {
		return;
	}

	if ( 'publish' === $post->post_status ) {
		return;
	}

	$wpdb->update( $wpdb->posts, array( 'post_status' => 'publish' ), array( 'ID' => $post->ID ) );

	clean_post_cache( $post->ID );

	$old_status        = $post->post_status;
	$post->post_status = 'publish';
	wp_transition_post_status( 'publish', $old_status, $post );

	/** This action is documented in wp-includes/post.php */
	do_action( "edit_post_{$post->post_type}", $post->ID, $post );

	/** This action is documented in wp-includes/post.php */
	do_action( 'edit_post', $post->ID, $post );

	/** This action is documented in wp-includes/post.php */
	do_action( "save_post_{$post->post_type}", $post->ID, $post, true );

	/** This action is documented in wp-includes/post.php */
	do_action( 'save_post', $post->ID, $post, true );

	/** This action is documented in wp-includes/post.php */
	do_action( 'wp_insert_post', $post->ID, $post, true );
}