If someone were to write code to their software fixing bugs, how and why can that break other code/features if it’s not meant for that? A common example are Nvidia drivers “breaking” or Microsoft patching one feature but breaking many, many other features.
If code is meant to be hyper specific, how can it affect any other feature?
I’m system design there’s almost always a tension between efficiency and adaptability / robustness.
You can write software where code is very isolated and not shared and it makes it really easy to update it quickly and ship it and know that it will run properly, but the cost is usually that there’s more boundaries in the software that create little slowdowns and cause things to have to repeat and it adds up to a slower or more bloated program.
You also have instances where you write your software and it has a bug, and you later go to fix that bug, and you don’t realize that a whole bunch of other software relied on that bug being there.
For instance the Node.js team recently released a security patch that caused them to emit a proper .closing event. Unfortunately an old version of a very popular fetching library breaks when it receives that .closing event because is thought it was supposed to close. It’s fixable but it would be very hard for the node team to know that they would break another piece of software that was listening to undocumented events.