It's esoteric because in reality it's the kind of bug that never happens. And if it happens it's trivial to identify the cause; "Oh, it hangs in the middle of a

It's esoteric because in reality it's the kind of bug that never happens. And if it happens it's trivial to identify the cause; "Oh, it hangs in the middle of a strack-trace, what could it possibly be...". Why would your code contain repr()-functions that trigger "unpredictable behavior" to begin with anyway?