I was trying to find alternatives to the use of global variable in some legacy code. But this question is not about the technical alternatives, I'm mainly concerned about the terminology.
The obvious solution is to pass a parameter into the function instead of using a global. In this legacy codebase that would mean that I have to change all functions in the long call chain between the point where the value will eventually be used and the function that receives the parameter first.
higherlevel(newParam)->level1(newParam)->level2(newParam)->level3(newParam)
where newParam was previously a global variable in my example, but it could have been a previously hardcoded value instead. The point is that now the value of newParam is obtained at higherlevel() and has to "travel" all the way to level3().
I was wondering if there was a name(s) for this kind of situation/pattern where you need to add a parameter to many functions that just "pass" the value unmodified.
Hopefully, using the proper terminology will allow me to find more resources about solutions for redesign and describe this situation to colleagues.
Best Answer
The data itself is called "tramp data". It is a "code smell", indicating that one piece of code is communicating with another piece of code at a distance, through intermediaries.
Refactoring to remove global variables is difficult, and tramp data is one method of doing so, and often the cheapest way. It does have its costs.