I wrote this file, and I cannot read it.
That is the whole confession. There is no twist coming. The file is called billing_reconcile.py. It is 214 lines long, and every one of those lines was typed by me, eight months ago, in a week I barely remember. I opened it on a Tuesday morning because a customer had been charged twice for the same order. $63.20, twice. Someone had to find out why. That someone was me. I stared at the first function for eleven minutes. I know it was eleven minutes because I checked the clock twice, the way you check the clock in a waiting room.
The function was called normalize_line_items. I remembered writing the name. I remembered feeling good about the name, the way you feel good about naming a dog. What I did not remember was what it did. It took a list in, gave a list back, and in between it did something with a dictionary, a date, and a variable called temp2. There was a temp2. Which means there was a temp1 somewhere, and I could not find it, and I did not want to know what temp1 had done to earn its number.
My own comments were the worst part. I had left comments. I am the kind of person who leaves comments, and I say that the way people say they floss: proudly, and not entirely truthfully. Above the trickiest block there was a comment that said: "# don't touch this, it works." That was all. No explanation of what "this" was. No explanation of what "works" meant. Just a warning from a stranger who happened to have my name on the commit.
Another one said: "# TODO: fix later (it is later)." I had written that. I had written a joke to myself, eight months ago, and then forgotten the joke and the fix. Past me thought he was funny. Past me was also, apparently, in a hurry.
I should explain the hurry, because the hurry is the whole story, and it is also the excuse I have been rehearsing in case anyone asks.
Eight months ago, we had a deadline. A client was going live on Friday, and the billing page had to stop double-charging people by Thursday, and the fix landed on me on Wednesday afternoon, because I was the only one who had touched that part of the code before. I was. I had touched it. Once. Six months before that. I said yes anyway, because "yes" is the easiest word in the world when someone is standing at your desk.
I wrote the file on Wednesday night, starting at about nine, finishing at about twenty past midnight. I remember the shape of the night better than the code: the music too loud, the coffee gone cold twice, the feeling of going fast. Fast is a drug when you are behind. Every line worked on the first try, or the second, and I did not stop to ask why. I named a variable temp2 because temp1 was taken and I was in no mood to negotiate with myself. I wrote "# don't touch this, it works" at 12:07 a.m., and I meant it as a note to future me, and future me read it eight months later and understood none of it.
The demo went fine. The client went live. The file sat there, working, like a locked room in my own house. I never opened it again. Why would I? It worked. That was the deal I had made with it: it works, I don't touch it. Eight months of peace, bought with one comment.
Then Tuesday morning, the double charge. $63.20, twice. And there I was, standing outside the locked room, holding a key I had made myself, unable to remember which way it turned.
I did what anyone does in that position. I lied, a little, and bought time. I told the team I was going to clean the file up before I fixed it. "Refactor" was the word I used. Refactor is a wonderful word. It sounds like work. It sounds like improvement. It sounds like a man who understands the thing he is about to improve. What I actually did was sit down and re-learn my own code from scratch, the way you would re-learn a language you spoke as a child, one line at a time, with a notebook open beside me.
I started at the top and worked down, writing what each block did in plain words, like a translation. "This part takes the messy list from the payment page." "This part checks the dates." "This part, I think, throws away the duplicates." By noon I had three pages of notebook and a headache. By two o'clock I had found the bug. It was in the part I had marked "don't touch." Of course it was. The duplicate check compared the wrong two things, and it had been comparing the wrong two things for eight months, and the only reason nobody had noticed was that the wrong two things were usually the same. Usually. Not always. Not on Tuesday.
I fixed it in four lines. Four lines, after five hours of reading. I sat there for a while after the fix, looking at the notebook. Five hours of reading, four lines of fix. I decided to think about something else.
The dread, though, was not the bug. The dread was standup the next morning. I could already hear it: "Salam, can you walk us through the billing fix?" And I would have to stand there and walk six people through a file I had only just learned to read, and someone would ask why temp2 was called temp2, and I would have to say "because I was in a hurry at midnight" in front of everyone. I spent the evening drafting my answer in my head, the way you draft a text you never send, and every version sounded worse than the last.
Priya found me at my desk the next morning, still staring at the notebook. Priya sits two desks over. She has been doing this longer than me, and she has the calm of a person who has seen worse. She looked at my notebook — three pages of translation, boxes, arrows, one frustrated doodle of a locked door — and she said, "Yours too?"
"Yours too?" I said.
She told me about her file. It is called email_digests.py. She wrote it a year ago, in a week she describes as "a blur with a deadline in it." She opened it last month and could not follow it. Her comment, the one she remembers, says: "# I don't know why this works and I am afraid to find out." She said it the way you admit you still sleep with the light on sometimes. Not proud. Not ashamed either. Just true.
We sat there for a while, two people who had written code they could no longer read, with coffee going cold on both our desks. Then she said, "I started leaving notes. At the top of every file. For future me. Like a letter." She showed me one, on her phone. It said: "Dear future me, this file sends the weekly email. The weird part in the middle is because Tuesdays are special. Sorry about Tuesdays. — past me."
That evening, I went back to my file and wrote one. At the top, above everything, in plain words:
"Dear future me, this file takes the messy list from the payment page and makes it tidy. The dictionary is the price list. temp2 is the discount. Sorry about temp2. — past me"
I saved the file. Two hundred and fourteen lines, and now the first four were a letter. The stranger and I were on speaking terms again.
P.S. Everything I write stays free — that part doesn't change. But if this one was worth something to you, you can buy me a coffee ☕ (one-time or monthly, both work). It covers the API credits and hosting behind these experiments — and honestly, it's also the nudge that gets the next one started on the evenings I'd otherwise skip it. — Salam
