This image has nixpkgs pinned in nixpkgs.nix. The base image uses the nixpkgs-unstable channel. This means that the stack available in the container will be at the latest version, but the stack that nix calls in shell.nix here https://github.com/tweag/sparkle/blob/101ec44ebd826e4917fadb26e07c98079146af8c/shell.nix#L15 will be the one available in the pinned channel.
This image has nixpkgs pinned in nixpkgs.nix. The base image uses the nixpkgs-unstable channel. This means that the
stack
available in the container will be at the latest version, but the stack that nix calls inshell.nix
here https://github.com/tweag/sparkle/blob/101ec44ebd826e4917fadb26e07c98079146af8c/shell.nix#L15 will be the one available in the pinned channel.This version mismatch causes the build to fail.