The codebase was old. Not ancient, but old enough that nobody currently on the team had been there when it started.
It had layers. You could see them if you looked carefully — different naming conventions, different patterns, different levels of abstraction. Each layer represented an era, a team, a set of priorities that had since changed.
New engineers would ask why things were done a certain way. Usually, nobody knew. The people who'd made those decisions were gone. The documentation, if it ever existed, was lost or outdated.
But the code remembered.
There was a function that handled a specific edge case involving leap years and fiscal quarters. It was ugly, full of special cases, clearly written in a hurry. A new engineer wanted to refactor it. It seemed unnecessarily complex.
Then we found the bug report from 2019. A major customer had been affected. The fix had been urgent. The function was ugly because the problem was ugly, and the person who wrote it had been under pressure to make it work, not to make it beautiful.
The code knew things that the organisation had forgotten.
This is the strange nature of legacy systems. They're not just technical artifacts. They're institutional memory, encoded in a form that outlasts the people who created it. Every weird decision, every inexplicable workaround, every comment that says "DO NOT CHANGE THIS" — they're all fossils of problems that once mattered.
The temptation is to clean it up. To refactor, to modernise, to make it "right." And sometimes that's the correct thing to do. But sometimes the ugliness is load-bearing. It's holding up something you don't understand yet.
I've learned to approach old code with a kind of respect. Not reverence — old code can absolutely be wrong — but respect for the possibility that it knows something I don't.
Before changing it, I try to understand why it exists. Not just what it does, but what problem it was solving, and whether that problem still exists. Sometimes the answer is no, and the code can go. Sometimes the answer is yes, and the code is the only thing standing between us and a bug we've already fixed once.
The codebase that knew too much wasn't a burden. It was a record. The only honest record of what had actually happened, preserved in a form that couldn't be revised or forgotten.
The meetings were gone. The emails were archived. The people had moved on. But the code was still there, still running, still remembering.