I'm trying to setup zsh on my nixos machine.
I currently have
programs.zsh = {
enable = true;
enableCompletion = true;
syntaxHighlighting.enable = true;
};
users.defaultUserShell = pkgs.zsh;
in my etc/nixos/configuration.nix.
This has the effect of starting zsh when I open a shell, as expected.
The unexpected thing is that zsh is asking me for additional configuration
This is the Z Shell configuration function for new users,
zsh-newuser-install.
You are seeing this message because you have no zsh startup files
(the files .zshenv, .zprofile, .zshrc, .zlogin in the directory
~).
I was expecting to be able to configure zsh directly with configuration in configuration.nix.
Is my expectation wrong? Should I necessarily have a .zshrc? If so, how are the configuration in configuration.nix and in .zshrc merged?
Your configuration.nix describes system-level configuration of packages. NixOS will use the options under programs.zsh.* to derive a system-wide zsh config file under /etc/zshrc.
On startup, zsh sources both /etc/zshrc and ~/.zshrc in that order (among other files). Since you don't have a ~/.zshrc, it assumes that you haven't set up zsh for this user, and drops you into the new user installation process.
There is no conflict between system-level and user-level zshrcs.
The easiest solution is just to put an empty zshrc in your home. (You could also specify the existence of this file declaratively in your nix config, or use home-manager for user level configuration.)