The installer script may fail in proot due to unrelated dependecies using new system calls

[deliciouslytyped]

I'm mostly just making a note here;

Using sh <(curl -L https://nixos.org/nix/install) from https://nixos.org/download.html , which invokes scripts in the nix codebase to install nix, can fail with strange issues when using proot, because proot shim's systemcalls, but does not whitelist them, leading to inconsistent processing.

If for example glibc or other such libraries migrate to a new system call interface (two examples are statx (not supported by proot 5.1.0) and faccessat2 (not in any proot release yet)), and proot does not support the new syscalls, proot will not warn about this and you will experience strange issues.

This is explained at https://nixos.wiki/wiki/Nix_Installation_Guide#Troubleshooting_2 and proot-me/proot#340 .

It would be nice if there was a CI test checking installation and invocation in proot on modern kernels. It provides a mechanism for the usecase of being able to use nix without any special permissions (some sites may not enable user namespaces; I have a concrete report of one such case in HPC.).