How much duplicated code do you tolerate?
In a recent code review I spotted a few lines of duplicated logic in a class (less than 15 lines). When I suggested that the author refactor the code, he argued that the code is simpler to understand that way. After reading the code again, I have to agree extracting the duplicated logic would hurt readability a little.
I know DRY is guideline, not an absolute rule. But in general, are you willing to hurt readability in the name of DRY?
Answer
Refactoring: Improving the Design of Existing Code
The Rule of Three
The first time you do something, you just do it. The second time you do
something similar, you wince at the duplication, but you do the duplicate
thing anyway. The third time you do something similar, you refactor.
Three strikes and you refactor.
Seibel: So for each of these XII calls you're writing an implementation.
Did you ever find that you were accumulating lots of bits of very similar code?Zawinski: Oh, yeah, definitely. Usually by the second or third time you've cut and pasted
that piece of code it's like, alright, time to stop cutting and pasting and put it in a subroutine.