Sometimes you can debug software by staring at the code for long enough

Once upon a time, when Ciro Santilli had a job, he had a programming problem.

A senior developer came over, and rather than trying to run and modify the code like an idiot, which is what Ciro Santilli usually does (see also experimentalism remarks at Section "Ciro Santilli's bad old event memory"), he just stared at the code for about 10 minutes.

We knew that the problem was likely in a particular function, but it was really hard to see why things were going wrong.

After the 10 minutes of examining every line in minute detail, he said:

I think this function call has such or such weird edge case

and truly, that was the cause.

And so, Ciro was enlightened.