Engineering blog
Longer write-ups on how TUIOS and its sibling tools were built, measured and fixed. Every number here came out of a run that can be repeated from the repository.
The bug I closed three times
A speckled sprite in the browser terminal. Three closures, each resting on a different wrong conclusion, a test suite blind by construction, and an instrument that was corrupting its own measurements.
I dragged one divider and five windows moved
One resize report turned out to be three separate defects, a wrong theory, and one behaviour that was correct all along. Benchmarks saw none of it. A log of who moved saw all of it in a single drag.
The benchmark said 27x faster. It felt worse.
Resizing a pane in TUIOS lagged behind the mouse. Go's profiling tools found the cause, killed two theories I was sure about, and then spent three rounds accurately measuring the wrong thing.
My fuzzer was optimising for my own bug
A flaky fuzz suite turned out to be a PTY I never configured, and a minimiser that hill-climbed straight toward the defect. It handed me the answer for two days while I ignored it.
My multiplexer lied about what it could do
Images worked in the terminal, worked in the multiplexer, worked in the browser client, and failed the moment you stacked all three. The middle layer was answering a capability question it had never asked anyone.
I ported a correct width table and it fixed nothing
Grapheme widths were wrong in the browser client, so I lifted the tables from an implementation that gets it right. Measured it. No change at all, for a reason that took me longer to see than it should have.
I shipped three fixes for a bug I had not found
A pane went blank when I focused a different one. I found and fixed three real bugs on the way to the actual cause, and shipped every one of them as the answer.
Three bugs in one month turned out to be one bug
A terminal is a request-response protocol that most people write as if it were one-way. I hit the same bug three times in a month, in three different codebases, pointing three different directions.