メモ：WPで記事の投稿日が最初の公開時に変更されるのを防ぐ

add_action('wp_insert_post_data', keep_the_post_date', 10, 3);

 
 function keep_the_post_date($data, $postarr, $unsanitized_postarr){
	  
	  if(is_admin() && in_array($data['post_status'], array('publish', 'pending', 'draft'))){
			
			$old = get_post($unsanitized_postarr['ID']);
			if($old && (!$old->post_date_gmt || $old->post_date_gmt == '0000-00-00 00:00:00')){
				$data['post_date'] = $old->post_date;
				$data['post_date_gmt'] = get_gmt_from_date($old->post_date);
			}
		  
	  }
	  
		return $data;
 }