> it's impossible to tell whether someone forgot to check an error How, exactly, does one find themselves in a situation where they forget to add entire blocks

> it's impossible to tell whether someone forgot to check an error How, exactly, does one find themselves in a situation where they forget to add entire blocks of logic to their application and not notice? We're not exactly talking about subtle bugs here. This is completely missing functionality – something that becomes immediately obvious as soon as testing begins. Which, I guess, means that the previous developer did no testing at all. In which case, where do you even begin to figure out what else they have forgotten? Such a codebase, no matter the language, may not even be salvageable at that point.