In reply to @roberthensing:matrix.org
John Ericson: I've suggested to treat the Nixpkgs "fix" for the CA placeholder issue (no storedir prefix) as a workaround as ca-derivations is experimental https://github.com/NixOS/nixpkgs/pull/386774#pullrequestreview-2660479310

Like:

warning: Ignoring dynamic derivation /nix/store/8apg4x2xbcx83xc0p1jk1qdiihkmhjyg-hello-2.12.1.drv.drv^out while querying missing paths; not yet implemented
error: Building dynamic derivations in one shot is not yet implemented.

https://discourse.nixos.org/t/determinate-nix-3-0/61202/80

Pure eval doesn’t exist outside of flakes (unfortunately), that flag is more or less a broken promise.

I wonder what was meant by that? Does it mean that nix-build --pure-eval doesn't actually perform evaluation purely?

And it's not like it's that difficult to use, I've ran nix darwin using this script for a couple of months just fine

{ pkgs ? import <nixpkgs> { }
, writeShellScriptBin ? pkgs.writeScriptBin
, directory
, ...
}:
writeShellScriptBin "darwin-rebuild-npins" ''
  set -eo pipefail

  pushd ${directory} > /dev/null

  echo "building the system configuration..."
  system=$(nix-instantiate --eval --expr builtins.currentSystem | tr -d \")
  systemConfig=$(nix-build --pure-eval --no-out-link --argstr system $system --argstr name $(hostname) --expr "import (
    builtins.path {
      path = \"$(pwd)\";
      sha256 = \"$(nix-hash --type sha256 --base32 .)\";
    }
  )" | tee /dev/tty)

  profile=/nix/var/nix/profiles/system

  if [ "$USER" != root ] && [ ! -w $(dirname "$profile") ]; then
    sudo nix-env -p "$profile" --set "$systemConfig"
  else
    nix-env -p "$profile" --set "$systemConfig"
  fi

  "$systemConfig/activate-user"
  if [ "$USER" != root ]; then
    sudo "$systemConfig/activate"
  else
    "$systemConfig/activate"
  fi

  popd > /dev/null
''