Why wouldn’t it allow that? Lockable tarballs are a thing.
$ cat flake.nix
{
inputs = {
nixpkgs.url = "https://channels.nixos.org/nixos-unstable/nixexprs.tar.xz";
};
outputs = _: {};
}
$ nix flake metadata
Resolved URL: path:/tmp/tmp.p8USHBfGyR
Locked URL: path:/tmp/tmp.p8USHBfGyR?lastModified=1760985208&narHash=sha256-fOMA%2BRP%2BKaxc7708i4NWyZmZIcuuobf44rSzmCjl6VM%3D
Path: /nix/store/4d7a2m07xch1kd8d1m5x3798ha3d1b74-source
Last modified: 2025-10-20 17:33:28
Inputs:
└───nixpkgs: https://releases.nixos.org/nixos/unstable/nixos-25.11pre880095.5e2a59a5b1a8/nixexprs.tar.xz?narHash=sha256-u0JUo46QSoXnjLaezAM75wRNuxVMVbm5OxHH122TeTY%3D&rev=5e2a59a5b1a82f89f2c7e598302a9cacebb72a67
Last modified: 2025-10-19 20:54:49