nix-direnv VS direnv

BTW: I personally use direnv with nix-direnv. This basically works by setting your shell with proper tooling when you enter the directory.

I'm not sure what you mean by nix env, maybe you are referring to nix-direnv?

Although currently I'm using direnv + nix-direnv. Keep in mind that direnv has builtin nix support which is very basic and doesn't do any caching. So you still needs this add-on to preserve roots.

I distinguish between system level things and user level things, even though I don't really have different users on my machine. I install the bare minimum number of packages + a lot of different drivers in the configuration.nix, and desktop and editor related things in HM. For development environment, I have environment per project using mkShell and https://github.com/nix-community/nix-direnv, which allows you to switch to the specific environment once you cd into the directory. (Although I do have python installed globally with some commonly used packages such as numpy, so I can just start python and write something when I need to, without creating an environment)

I further make my software projects so that when I click a link I go into an environment pre-loaded with their dependencies so dropping in/out of projects is always frictionless. I do this with the reproducibility guarantees of nix, along with glue like nix-direnv and envrc-mode to direnv.

(I also use nix-direnv)

direnv

Personally I use nix-direnv. No longer the need to run nix develop or nix-shell. By setting up a .envrc with either use nix or use flake it will automatically install all the packages from default/shell.nix or flake.nix

Direnv is installed using the nix-direnv installation instructions under "Via configuration.nix in NixOS". I read some recommendations that envrc.el is a better alternative then direnv.el, and after some testing I have to agree. (envrc-global-mode) is enabled in my config. This works perfectly with a normal emacs instance.

I think direnv already does a good job in this space, and it's already available in your package manager.

https://direnv.net/

I switched from asdf to mise after a comment on lobste.rs[1] suggested I do so a few months ago, and I have been very happy with it.

It sands off some of asdf's sharp UI edges and provides a somewhat larger but still reasonable feature set; I've also replaced most of my direnv[2] usage with it.

The mise -> asdf comparison page is useful[3]

1: https://lobste.rs/s/66uxbj/how_love_homebrew#c_mvmsjp

2: https://direnv.net/

3: https://mise.jdx.dev/dev-tools/comparison-to-asdf.html

I also made the export diff configurable, motivated by this post: https://github.com/direnv/direnv/pull/1233

Nice.

For years I've been using [direnv](https://direnv.net/) for this, setting environment variables which git picks up. This looks like a more feature complete equivalent, although to be honest I only really need switching of committer email and the SSH key used.

Direnv, for the uninitiated, loads and unloads environment variables when directories are entered and exited. Under every project folder there is a `$PROJ_DIR/.envrc` which contains:

buffer-env: A pure-Elisp version of the direnv utility. Useful to make Emacs aware of Python virtualenvs (which, judging by the questions posted here, is unfortunately still a complication for a lot of people). Similar to (and inspired by) envrc, but doesn't require the direnv program.

You can look at direnv to see this in action as they wrote shell hooks that get loaded into the shell profile and are executed on every prompt. https://direnv.net/

Yes, most Nix users employ https://direnv.net or the equivalent for your IDE of choice. Emacs for instance has https://github.com/purcell/envrc which set per-buffer variables.