This commenter is just wrong. denenv.nix pretty much is flake.nix + services. It has since grown more features, but this kind of use case is exactly its niche.
Devenv isn't a Nix fork and doesn't compete with Nix. Its scope is narrower and it's downstream of Nix. The code you write for configuring Devenv is ordinary Nix code. Its configuration system is a perfectly ordinary Nix module system.
There is a `devenv` CLI tool, and that CLI bundles a downstream soft fork of Nix that carries a few patches. Those patches exist to make it possible to read `devenv.nix` rather than `flake.nix` and use an easily programmatically editable yaml file for defining flake inputs. Other than that, all of the patches are just PRs that are open against mainline Nix that are included to speed up evaluation, notably the patchset for "lazy trees" or "source tree abstraction" (which is also in the Determinate Nix distribution of Nix).
But you can actually use the core features of Devenv (that is, the module system for configuring environments) without using the Devenv CLI or the patched evaluator. This isn't a hidden thing or a hack, either— it's documented on https://devenv.sh . It's always been this way, and isn't a paywall boundary or a trick. The whole of Devenv is open-source, and the vast majority of the code is Nix modules that you can use with any Nix implementation that you like (though flakes support makes it easier; Devenv's modules are exposed as flake-parts modules).
Hell, you can even use large subsets of devenv's functionality without using devenv at all. One of its key features is a Nix wrapper/integration for the pre-commit framework for managing git hooks. That whole subset of functionality is extremely loosely coupled to devenv, and lives in a separate repo. You can just import it as a flake-parts module with vanilla Nix without using devenv at all (i.e., not even the module system).
There's some code duplication with Nix (optional evaluator patches) and Nixpkgs (downstream release channel for guaranteeing integration with devenv's language configuration options, also optional (my team doesn't use it at all)), but it's extremely misleading to characterize Devenv as a fork of any Nix community projects including those two.
Just posting a link to the Devenv website is admittedly not a high-effort reply, but recommending Devenv is absolutely a fair reply to the post you linked. (Given that that post explicitly mentions not wanting to use Devenv, it definitely deserved a real conversation instead of what it got.)
PS: I'm not affiliated with devenv or Cachix. I just use it at work and know the code a little from times that I've filed bugs or submitted patches.
If this can work well generally, it's a really slick integration. I'm really impressed with Devenv's velocity and usefulness overall.
If you haven't checked devenv out yet, you definitely should. Don't be intimidated by the breadth of the feature set, either! It's really easy to use just the bits you're interested in and grow your usage (or not) organically.
It results into speed up in a way that if your application doesn't change, you'll just get the binary package.
That's why the two interfaces are exposed: one for development feedback cycle and one for distribution.
Think of devenv as systemd of developer environments.
I’m increasingly convinced that the mere existence of a package manager (for programs, not source code) is a sign of a failed platform design. The fact that it exists at all is a miserable nightmare.
Flatpak and Snap tried to make this better. But they do too much which just introduced new problems.
Steam does not have this problem. Download game, play game. Software is not that complicated.
Steam on Linux essentially has its own "package manager" which uses containerized runtimes: https://gitlab.steamos.cloud/steamrt/steam-runtime-tools
Nix is a build system for source code, similar to make. It is such a robust build system that it also can be used as a package manager with a binary cache
Real life software is much more than just downloading a game and running it.
Rebuilding? No. Linux package management is so-so at allowing you to compile programs. But they’re dogshit garbage at helping you reliably run that program. Docker exists because Linux can’t run software.
Real life software outside of Linux is pretty much just downloading and running it. Only in Linux we don't have a single stable OS ABI, forcing us to find the correct package for our specific distro, or to package the software ourselves.
> Steam does not have this problem. Download game, play game.
These statements seem contradictory. Steam is a package manager. So is the Apple App Store. Sure, they have different UX than, say, apt/dnf/brew/apk/chocolatey, but they're conceptually package managers.
Given that, I'm unclear what the gripe is (though I'm totally down to rip on Snap/Flatpak; I won't rant here, but I did elsewhere: https://news.ycombinator.com/item?id=44069483). Is the issue with OS/vendor-maintained package managers? Or is the issue with package installers that invoke really complicated build systems at install time (e.g. package managers that install from source)?
None of this has formal definitions which makes it difficult to discuss.
Your rant on Snap/Flatpak was great.
The core gripe is that I want running computer programs on Linux to be easy and reliable. It is not. MacOS and Windows are far more reliable, and they don’t require (imho) package managers to do it.