Well, updating can cause problems whenever you do it.
Technically, you should check the news feed for breaking changes whenever you update your system. Usually, the worst that happens is pacman just barfs. Then you can figure out why and apply any fixes.
Package metadata isn’t stored in text files because there’s an amazing technology called the database.
All you have to do is learn how to use your package manager. Spend time reading the man pages and learn the options, and you can query everything you need.