Monday, September 17, 2018

Software maturity

While reading a news article on Domain Driven Design over at InfoQ, I came across an interesting metaphor attributed to Eric Evans (i.e. the father of DDD):
A new metaphor Evans introduced was comparing a large software system to a community garden. Looking past the obvious bounded contexts of people sharing space in the garden, he sees positive analogies to legacy systems, looking at the "abundance of maturity." Gardens are most valuable in late summer, when they are most productive. However, that is long past the stage when you can easily make changes to the garden, in early spring. Similarly, the most malleable phase for software is not when it is the most productive.
This puts an interesting perspective on something I've noticed in my own career. Just like all developers, I love getting started on a new greenfield project: things are new and exciting and together with the team you're constantly inventing new ways of tackling problems and (re)factoring the system accordingly.

Some time after the first go-live, which typically comes with a host of teething problems, the application stabilizes and slowly evolves into a mature system over the next several releases. You can no longer reinvent the wheel at this time: you're building on the foundations you established earlier.
I've found that I also get a great deal of satisfaction from this phase: shepherding a system to maturity, seeing it come to fruition and hopefully realizing it's full potential! It as this time users are most happy with what has been delivered: the software is well understood and quality is still high, making changes predictable and quick.

Over time quality slowly deteriorates and accidental complexity grows. Changes become more difficult and risky, with more regressions slipping in. Ultimately the system is replaced with something new and better, bringing everything full circle, just like in a garden.