> It's better to have some wonky parameterization than it is to have multiple implementations of nearly the same thing. Improving the parameters will be easier than to consolidate four different implementations if this situation comes up again.

From https://go-proverbs.github.io/: A little copying is better than a little dependency.

Curious to see how the community is divided on this, I think I'm more leaning towards the single implementation side.

> Copy-paste is OK once. The second time you're introducing duplication (i.e., three copies), don't. You should have enough data points to create a good enough abstraction. The risk of diverging implementations of the same thing is too high at this point, and consolidation is needed. It's better to have some wonky parameterization than it is to have multiple implementations of nearly the same thing. Improving the parameters will be easier than to consolidate four different implementations if this situation comes up again.

The more I do this software engineering thing the more I feel like this “advice” bites me in the butt. Understanding when you should duplicate code versus when you should consolidate (or if you should just write a TODO saying “determine if this should be split up by [some set in stone timeline]”) is simply just a HARD problem (sometimes at least), and we should treat it as such.

DRY/ WET or whatever shouldn’t be a maxim (let alone a habit! lol), it should at best be a hand-wavey 2-bit dismissal you give an annoyingly persistent junior software dev who you don’t want to actually help!

> Copy-paste is OK once. The second time you're introducing duplication (i.e., three copies), don't. You should have enough data points to create a good enough abstraction. The risk of diverging implementations of the same thing is too high at this point, and consolidation is needed.

This heavily depends on how likely it is for the reasons of change to also apply to the other copies. If the reasons for why the code is the way it is are likely to evolve differently for the different copies, then it’s better to just leave them as copies.

Just being the same code initially is not a sufficient reason to create an abstraction. Don’t focus on the fact that the code is currently the same, instead focus on whether a change in one copy would necessarily prompt the same change in the other copy.

This also applies to pieces of code that are different from the beginning, but are likely to have to change in conjunction, because they rely on shared or mutual assumptions. If possible place those pieces of code next to each other, and maybe add a source comment about the relevant mutual assumptions.

In other words, avoiding code duplication is a non-goal. Keeping code together that needs to evolve together is a goal. Instead of DRY or WET (don’t repeat yourself, write everything twice), think SPOT (single point of truth).

"Know when you're testing the framework's capability. If you are, don't do it."

Hard disagree on that. Frameworks change over time. How certain are you that they won't make a seemingly tiny design decision in the future that breaks your software?

One of the most valuable things tests can do for you is to confirm that it is safe to upgrade your dependencies.

If all your test does is duplicate tests from dependency that might be a waste of time... provided that's a stable, documented feature and not something that just happens to work but isn't necessarily expected stable behavior.

But you shouldn't skip testing something because you're confident that the dependency has already covered that.

The tests should prove your software still works.

> It's better to have some wonky parameterization than it is to have multiple implementations of nearly the same thing. Improving the parameters will be easier than to consolidate four different implementations if this situation comes up again.

Hard disagree. If you cant decompose to avoid "wonky parameters" then keep them separate. Big smell is boolean flags (avoid altogether when you can) and more than one enum parameter.

IME "heavy" function signatures are always making things harder to maintain.