Do the simplest thing that could possibly work

One of the ironies of this kind of advice is that it's best for people who already have a lot of experience and have the judgement to apply it. For instance, how do you know what the "simplest thing" is? And how can you be sure that it "could possibly work"?

Yesterday I had a problem with my XLSX importer (which I wrote myself--don't ask why). It turned out that I had neglected to handle XML namespaces properly because Excel always exported files with a default namespace.

Then I got a file that added a namespace to all elements and my importer instantly broke.

For example, Excel always outputs <cell ...> whereas this file has <x:cell ...>.

The "simplest thing that could possibly work" was to remove the namespace prefix and just assume that we don't have conflicting names.

But I didn't feel right about doing that. Yes, it probably would have worked fine, but I worried that I was leaving a landmine for future me.

So instead I spent 4 hours re-writing all the parsing code to handle namespaces correctly.

Whether or not you agree with my choice here, my point is that doing "the simplest thing that could possible work" is not that easy. But it does get easier the more experience you have. Of course, by then, you probably don't need this advice.

I gauge it as "the simplest thing to transition". Most of the time, it's easier to transition a single service that doesn't rely on a big number of complex abstractions or extra infrastructure, even if it's at the expense of some clutter or a bit of redundancy. The new owner can step through the code and see what's going on without having to work backward to understand the abstractions or coordination of services or whatever else.

Of course plenty of times there'll be some abstractions that make the code easier to follow, even at the expense of logic locality. And other times where extra infrastructure is really necessary to improve reliability, or when your in-memory counter hack gets more requirements and replacing it with a dedicated rate limiter lets you delete all that complexity. And in those cases, by all means, add the abstractions or infrastructural pieces as needed.

But in all such cases, I try to ask myself, if I need to hand off this project afterward, which approach is going to make things easiest to explain?

Note that my perception of this has changed over time. Long ago, I was very much in the camp of "simple" meaning: make everything as terse as possible, put everything in its own service, never write code when a piece of infrastructure could do it, decouple everything to the maximum extent, make everything config-based. I ironically remember imagining how delighted the new owners would be to receive such a well-factored thing that was almost no code at all; just abstraction upon abstraction upon event upon abstraction that fit together perfectly via some config file. Of course, transition was a complete fail, as they didn't care enough to grok how the all pieces were designed to fit together, and within a month, they'd broken just about every abstraction I'd built into it, and it was a pain for anybody to work with.

Since then, I've kept things simpler, only using abstractions and extra infra where it'd be weird not to, and always thinking what's going to be the easiest thing to transition. And even though I'm not necessarily transitioning a ton of stuff, it's generally easier to ramp up teams or onboard new hires or debug problems when the code just does what it says. And it's nice because when a need for a new abstraction becomes apparent, you don't have to go back and undo the old one first.