In pondering "systems that went wrong", I've noticed certain patterns in how they go wrong and patterns in the symptoms. I'll propose a
UsefulLie dichotomy between idealistic messes and "lazy" messes.
Idealistic,
GoldPlating, and
MentalMasturbation messes:
- Difficult to figure out what any piece of code does
- Difficult to trace the impact of a change due to too many layers of indirection
- Wrong abstraction used, resulting in big DiscontinuitySpikes. Some changes that fit the abstractions are quite easy, others are nearly impossible.
- Unlike lazy messes, you spend more time studying code than typing code to fix it.
- Inconsistent use of different paradigms or techniques.
- Lots of wasted code for dead-end or unfinished concepts.
Lazy messes:
- Lot's of violation of OnceAndOnlyOnce, so prepare to type a lot to change or fix.
- Generally a consistent pattern
- Lots of code to do relatively little
- Lots of similar-looking IF statements or viney, repetitious sub-classing for endless exceptions to the rule.