The dev shell inherits environment, but the builds don't. Having a dev shell inherit none of your environment is possible but an inconvenient default, you can d

The dev shell inherits environment, but the builds don't. Having a dev shell inherit none of your environment is possible but an inconvenient default, you can do this with `--ignore-environment`. `nix build .#somePackage` is pure by default, as is `nix flake check` I believe `nix shell` also inherits environment by default for the same reason. People expect to be able to run the packages they installed system wide after entering a shell.