In this chapter, we discussed a surprising aspect of XP, that of the concept of doneness (or lack of it). We contrasted this with XP s optional-scope contract, which at first glance appears to contradict the Extremo attitude to doneness ” but turns out to be the opposite side of the same coin.
We also discovered that the emergent design approach runs a high risk of leading to emergent entropy, where the design quickly breaks down into spaghetti code unless it is constantly fought with the chief weapon of refactoring. We discuss emergent design in more detail in the next chapter.