[macintux]

Agreed, but that’s why I prefer writing code that has no global state. In Erlang, for example, it’s unusual (and the language lends itself via pattern matching to having short function clauses).

It gets a little tiresome threading the relevant state to every function that needs it, but it’s worthwhile in the end.

[emn13]

Even a pure function has "state" - namely its (arbitrarily complex) inputs. But sure, it's a little less of a landmine.

The fundamental issue remains that sometimes your knowledge about that state (whether the classical kind or a proper parameter) can be complex and dependent on what happened elsewhere, especially if the codebase your in was grown into that situation, and not designed like that per-se. A comprehensible set of preconditions and postconditions isn't always a luxury you have, certainly not at first.