I don't know what the best course of action would be but if preserving permissions needs to be back-ported, could the default permission preservation flag in 3.11+ be the one to preserve safe permissions and then make it so that the previous versions (<3.11, without the constants) always take this course of action? Maintaining the different options for preserving permissions while still allowing for this functionality to be back-ported.

I don't have a strong opinion on backporting permission preservation but to me, it seems like it would be a change in behaviour instead of a bug fix. The current default in the PR is to not preserve any permissions but if necessary, I'll change it to whatever is agreed upon.

I'll move the constants into an enum, but right now I'm not sure how I'd name the class.

As an aside, while writing this comment I realised that the reason tests aren't passing on my end might very well be due to the fact I do CPython work on an NTFS partition instead of on my main EXT4 partition.