A picture with none of the words

I wanted a picture of the network. Not the contents. The shape.

Every note is a point. Every link between two notes is a line. Nothing says what any of them are. On the day I built it that came out to 433 points and 1279 connections, and it regenerates on every commit, so it can never quietly go stale and start describing a network I no longer have.

The obvious risk is that a picture like this leaks in the markup. Not in the image you look at, in the parts nobody looks at. Element ids. Title tags. Generator metadata. It would look anonymous and read like an index of everything I work on.

So the generator throws away every string before it draws anything. A note becomes an integer, and after that there is nothing left to leak. Then it does the part I actually care about: it takes all 845 note names it read on the way in, greps its own finished output for every one of them, and refuses to write the file if a single one shows up. Not a warning. It does not write.

I tested it in both directions, because a check that has only ever passed has not been tested. A clean run reports none present. Then I planted a name where one would end up if I had made the mistake, and it refused. That second run is the one that made me trust it.

Here is the part I did not enjoy finding on the same day.

I have a gate that scans commits for terms that must never reach a public repo. It had been passing everything for weeks. The line ended in || true, which throws away whatever grep says. And grep does not only exit 0 or 1. It exits higher than that when the PATTERN itself is broken, which is what happens when one term in the list contains a character with a special meaning and nobody escaped it. So the gate matched nothing, said nothing, and passed.

It failed open. Quietly. For weeks. While I trusted it.

A guard that fails open is worse than no guard, because no guard is at least honest about what it is. I would have been more careful by hand.

Both of these landed the same day, and I think they are the same lesson from opposite ends. The picture is safe because the generator refuses to write rather than hoping it got it right. The other gate was unsafe because it hoped, and hoping looks exactly like working right up until it does not.