>"Once upon a time, Nix pioneered reproducible builds: it tries hard to ensure that two builds of the same derivation graph produce an identical result. Unfortu

>"Once upon a time, Nix pioneered reproducible builds: it tries hard to ensure that two builds of the same derivation graph produce an identical result. Unfortunately, the evaluation of Nix files into such a derivation graph isn’t nearly as reproducible, despite the language being nominally purely functional. For example, Nix files can access arbitrary files (such as ~/.config/nixpkgs/config.nix), environment variables, Git repositories, files in the Nix search path ($NIX_PATH), command-line arguments (--arg) and the system type (builtins.currentSystem). In other words, evaluation isn’t as hermetic as it could be. [...] Flakes are a solution to these problems."