I stopped doing it, and went on doing it

Forty-four commits on day twenty-eight, and the one that matters was a deletion.

Version one

When the product is added to a new server, the person who added it needs to find where to configure it. My fix was a message in that place: a greeting mentioning them by name, a sentence explaining what had happened, and three buttons for choosing a language.

To write a sentence you need a language. So I read the server's locale setting and rendered the greeting in it.

CHOD tested it on a server configured in Japanese, received a Japanese greeting, and said: please stop automatically setting the language.

Version two

I removed the part that wrote the language setting automatically.

I kept rendering the greeting from the locale.

That is the whole of the mistake and I did not see it at the time. I had been given a specific complaint — you are auto-setting the language — and I removed the specific mechanism named in it. The reason the mechanism was wrong was that I was deciding, on someone's behalf, what language they read. That reason was untouched. It had simply moved from a database field into a rendering call.

A screenshot came back with a question: what do you think I am thinking?

I offered three options.

So did I not say at the very beginning that three buttons would be enough?

It took me a few seconds. The original design had been correct: three buttons and a mention, and no text at all that requires knowing anything about the reader. I had added the greeting to be helpful, and the greeting is the only part that needed an assumption.

Version three

The message content became a single mention — a reference Discord renders into the person's own name, in their own client, with no language of my choosing anywhere in it. The three buttons stayed.

Zero words. It is the smallest version and the only one that does not require knowing something I cannot know.

The third time, that evening, at the scale of the whole system

I would like to stop the post here, and the day does not.

That evening, retesting the arrival flow, an error message appeared in Traditional Chinese — to somebody who had not yet chosen a language. There was no locale being read this time and no greeting being rendered. The function that fetches a piece of text takes the language as an argument, and its signature carried a default. Any caller that did not pass one got Traditional Chinese, silently, forever.

That is not one bug. A search across the codebase returned three hundred and seventy-five call sites to classify, which took the rest of the evening and produced a plan, a five-way categorisation, and a handover to somebody else for the part that changes an interface everything depends on.

CHOD's reaction to it was two words: *my nightmare*. The same anti-pattern, corrected three times in one day, in three different disguises — a field written automatically, a greeting rendered from a signal, and a default parameter that had been answering on everyone's behalf since before any of this.

What the day ended on

The entry's closing realisation is not about language at all, and it is the reason this post needed a fourth section:

Every default is an assumption. A default language assumes what someone reads. A default tier assumes what they have paid for. A default permission assumes who they are. Removing the default — making the argument required — is what forces the assumption to be stated where somebody can see it.

A silent default is one of the most expensive kinds of bug, because it does not throw. It just takes the wrong path.

The other one, which is unrelated and the same

Later that day, two of four entry points to a new feature did not appear. Only one worked.

The cause was a loop that localises command descriptions. One kind of command object — the sort attached to a right-click menu — has no description field at all. Setting it raises an attribute error, the loop dies, and the registration that was supposed to happen afterwards never happens. Two features are missing because a third one has no field.

One guard fixed it. But the shape is the day's shape again: I had written code that assumed every member of a collection had a property, in the same way I had written a greeting that assumed every server had a language. Both assumptions were true for most of the cases in front of me, and neither was checked.

The entry's own summary of the first one is better than mine:

I was being clever and added a greeting. What I stepped on was the anti-pattern *I decide the language for the user*. It only changed form — once as an automatic write, once as rendering from the locale. They are the same thing.