poetry2nix template overrriding registry pining

[hhoeflin]

Thanks for providing the template. I am pretty new to flakes, so maybe I am just making a mistake here, but I observed the following.

I am pining my nixpkgs in the registry to a previous commit and created a poerty application with your template. Checking if the flake uses my pinned commit, I observed it did not. Looking for the reason, I assumed that

nixpkgs.url = "github:NixOS/nixpkgs";

in the input is responsible, which is not an flake reference, but an explicit reference to the github repo. I was just wondering if this intentional, i.e. what the motivation is for providing the explicity github url rather than relying on the global flake registry?

Thanks