[whathaschanged]

So ctrl-f and ctrl-v using the diff as needed?

I wonder if the man hours wasted on hunting through someone else's code to figure out the bajillion abstracted functions are doing when you are trying to make a change outweigh the minor inconvenience of copying and pasting changes are? Yes the latter introduces more opportunities for errors, but are they more than knowing all your dependencies and ensuring your changes don't break their expectations? Unit tests are only as useful as the man who knows the future.

[sanderjd]

That's basically what I'm saying: it's unknowable whether copying and pasting and needing to keep all the copies up to date in the future will result in more or less work and bug fixing than re-using code. I think the best solution is for experienced developers to make an educated guess on a case by case basis. But you can't write that into a generic principle.