I think the hatred of global variables comes from the fact that they are hard to use correctly. This article also makes the point that to use correctly you need to follow a bunch of rules.
I’m normally open minded about what I read posted here but that article does nothing but frustrate me. I can’t count the amount of times I’ve dealt with legacy spaghetti code that used global variables and the pain and suffering that results from that.
Exactly the issue; inevitably someone will forget to follow those rules, at which point esoteric bugs will have been introduced.
I think it’s somewhat similar to unchecked memory access. Used correctly it works just fine and offers extremely high performance. Unfortunately, history has shown that over enough time mistakes will be made. As an industry we’re now to the point of actively denouncing entire languages over the risks of unchecked memory access.
Using software development patterns that rely on the engineers to follow a bunch of rules to do things correctly will eventually burn you. Better to avoid them entirely if at all possible.
There's plenty of things in programming that are "hard to use correctly". I seen many codebases that you must clone an object because passing it in a function because there was so much spaghetti data structures that you'd end up accidentally mutating something you didn't mean
