File is in the way of symlinking (shell history, .zsh_history)

[yeldiRium]

I'm trying to persist my zsh history using the home manager impermanence module like this:

{
  home = {
    persistence = {
      "/persist/${config.home.homeDirectory}" = {
        files = [
          ".zsh_history"
        ];
      };
    };
  };
}

Most of the time this works fine. Sometimes, when switching, the activation script fails.
I assume this is the case because some zsh session is writing to the file in the wrong moment, and a regular file exists when home manager tries to symlink over it. The systemd unit logs this:

...: Activating checkLinkTargets
...: Existing file '/home/yeldir/.zsh_history' is in the way of '/nix/store/wwvczw7sk7gnxn4gf0gkb0kd1x182x1x-home-manager-files/.zsh_history'
...: Please do one of the following:
...: - Move or remove the above files and try again.
...: - In standalone mode, use 'home-manager switch -b backup' to back up
...:   files automatically.
...: - When used as a NixOS or nix-darwin module, set
...:     'home-manager.backupFileExtension'
...:   to, for example, 'backup' and rebuild.

I don't think this is a bug in impermanence and I also don't have a suggestion on how to prevent this code-wise.

I just want to ask: Has anyone done something similar? Has anyone solved this or a similar problem?

[body20002]

I read somewhere to do something like

home-manager.backupFileExtension = "backup-"
      + pkgs.lib.readFile
        "${pkgs.runCommand "timestamp" {} "echo -n `date '+%Y%m%d%H%M%S'` > $out"}";

but it doesn't really work if you try to build multiple times not sure why :/