When I wrote similar functionality, we had (as you mentioned) various helper functions. All of them where heavily tested and marked for extra code review if th

When I wrote similar functionality, we had (as you mentioned) various helper functions. All of them where heavily tested and marked for extra code review if they were changed. And if you need a temp or cache dir, systems provide safe ways to create such -- eg mktemp, GetTempPath, etc. And it's more than fair for the lead who approved the code change, and perhaps even the lead who approved the entire design to have their jobs on the line for this.