> You absolutely do not want multiple (even just two) copies of what's meant to be exactly the same functionality, since now they can accidentally evolve separately. But coupling together things that only happen to be mostly similar even at the expense of complicating their implementation and interface just makes things harder to reason about and work with.
So, if things are fundamentally the same, do not duplicate, but if they are fundamentally different, do not unify. This is absolutely correct.
To which you replied:
> People who follow that simplistic logic of "code can accidentally evolve separately" are completely oblivious to the fact that there is seemingly duplicate code which is only incidentally duplicate, but at its core should clearly be and remain completely decoupled.
Despite the fact that this is exactly what the comment you replied to says.
Then you go on a clearly very deeply felt rant about overcomplication via dependency injection and architecture astronautics and so on. Preach it! But this is also nothing to do with what thfuran wrote.
"Know the future" is part of a software engineer's job description, at least insofar as "know" means "make informed predictions about".
Consider the case of making API calls to a third party. You, today, are writing a function that calls the remote API with some credentials, reauthenticates on auth failure, handles backoff when rate limited, and generates structured logs for outgoing calls.
You need to add a second API call. You're not sure whether to copy the existing code or create an abstraction. What do you do?
Well, in this case, you have a crystal ball! This is a common abstraction that can be identified in other code as well as your own. You don't know the future with 100% confidence, but it's your job to be able to make a pretty good guess using partial information.
I think this is what the original post that people took issue with said? By the time you write the same thing for the third time you are not predicting the future any more, you have practical evidence.
But a thing that you wrote the same a few times isn't something that's definitively required to be the same, it's something that happens to be the same right now. You can often clean things up by factoring out that duplication, but needing to add a bunch of parameters to the resulting function is probably a sign that you're trying to combine things that aren't the same and shouldn't be coupled together.
Where I'm saying you absolutely shouldn't copy paste is where there's a business or technical requirement for something to be calculated/processed/displayed exactly a certain way in several contexts. You don't want to let those drift apart accidentally, though you certainly might decouple them later if that requirement changes.
> You absolutely do not want multiple (even just two) copies of what's meant to be exactly the same functionality, since now they can accidentally evolve separately. But coupling together things that only happen to be mostly similar even at the expense of complicating their implementation and interface just makes things harder to reason about and work with.
So, if things are fundamentally the same, do not duplicate, but if they are fundamentally different, do not unify. This is absolutely correct.
To which you replied:
> People who follow that simplistic logic of "code can accidentally evolve separately" are completely oblivious to the fact that there is seemingly duplicate code which is only incidentally duplicate, but at its core should clearly be and remain completely decoupled.
Despite the fact that this is exactly what the comment you replied to says.
Then you go on a clearly very deeply felt rant about overcomplication via dependency injection and architecture astronautics and so on. Preach it! But this is also nothing to do with what thfuran wrote.
> Newbie, inexperienced developers write complex code. Experienced, seasoned developers write simple code.
Sounds like the kind of overgeneralisation that overconfident mid-career developers make to me.