Issue on page /tutorials/ad-hoc-developer-environments.html

[aes]

The source of the link https://github.com/NixOS/nixpkgs/archive/2a601aafdc5605a5133a2ca506a34a3a73377247.tar.gz is not explained. Is this just something everyone should cargo-cult?

[henrik-ch]

I have had exactly the same issue as you.
This is something we should create a PR for and resolve.

Looking at this discourse:
https://discourse.nixos.org/t/how-to-install-a-specific-version-of-a-package-from-my-configuration-nix/18057/4
in that thread mapybara has this description:
look at the commit - change commit to archive, and add .tar.gz.

so for your example, we can find that commit that is referenced like this:
NixOS/nixpkgs@2a601aafdc5605a

There is also a different possibility to link to the release branches I believe, but I don't understand how that works yet.

[fricklerhandwerk]

Fixed as a side effect of #447

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/tweag-nix-dev-update-44/25546/1

[proofconstruction]

Fixed with #447 and the tutorial on pinning nixpkgs