`builtins.fetchGit` causes repeated source fetches during evaluation

[definfo]

https://github.com/shezdy/hyprsplit/blob/a1f95ac05279ede3e4b6926464f1ba10d4d8a128/flake.nix#L31C1-L38C20

        src =
          if (commitPins ? ${hyprland.rev}) && (self ? rev)
          then
            (builtins.fetchGit {
              url = "https://github.com/shezdy/hyprsplit";
              rev = srcRev;
            })
          else ./.;

Fetching source with builtins.fetchGit will not produce a fixed-output-derivation (FOD), which means the fetcher will be executed repeatly each time this package is evaluated.

I think it is enough to notice Nix flake users to follow tag (e.g. v0.51.0) in this repo for consistency with Hyprland. Correct me if I got it wrong 🤔