> What if the bug is in 3rd party library?

It will probably be similar to when a physical product is defective because of a faulty 3rd party component.

More importantly, as a professional software developer, the testing of my product should find problems in 3rd party components. If I chose poorly and the 3rd party component doesn't do what it's supposed to do, that's my responsibility. I can't just slough it off onto someone else.