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2024 Election for the Steering Committee
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What are your thoughs about bringing Grafts to Nix? #115

Open lucasew opened 1 month ago

lucasew commented 1 month ago

Question

Grafts are a way from Guix to bring fixes to packages that a lot of other packages depend on without having to rebuild the world basically.

What are your thoughs about bringing a equivalent feature to Nix?

[1] https://guix.gnu.org/blog/2020/grafts-continued/

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cafkafk commented 1 month ago

We do in fact have replaceDependencies and replaceRuntimeDependencies, but my very shallow understanding of both of these is they have downsides that make them not at all equivalent. As I have outlined elsewhere, I think the graft system would likely be very useful, and as Delroth (the contributor on the front-line of dealing with the libwebp vulnerability) outlined in a post[1], these are useful, albeit slightly hacky tools for fast security mitigations.

[1]: The post in question https://delroth.net/posts/nixos-security-wishlist/

@doronbehar asked where to read more about this, there isn't a mention in the NixOS/Nixpkgs manual, or Nix reference, but you can read about it in the source code of nixpkgs

tomberek commented 1 month ago

Our current mechanisms are not very easy to use (try replacing a self-referential glibc!). But the idea is worth pursuing, I have a done a little bit myself. And so are the alternatives. I don't really see this as an either-or situation, so people should be free to pursue these developments independently.

doronbehar commented 1 month ago

We do in fact have replaceDependencies and replaceRuntimeDependencies

Could you please share an official documentation for that? I couldn't find any :smile: .

winterqt commented 1 month ago

I'm a big fan of Guix's ideas around UX/DX in general (despite implying the opposite in my candidacy doc ;)), and I think grafts would be a good thing to have. I've napkin-sketched some ideas for an implementation of them before, but it never really got off the ground. I would love for this to be done eventually.

proofconstruction commented 1 month ago

On the surface, this seems like a good idea. I can think of a few ways this might be implemented today, and it should be substantially easier still once content-addressed derivations land (handwaving some very important architectural assumptions, of course).

I invite anyone to submit an RFC for this! We could learn a lot from our Guix friends.

Infinidoge commented 1 month ago

Grafts are a useful tool that I think Nix could definitely use. (Mass rebuilds for a quick security fix is... suboptimal when it needs to be deployed quickly.) Whether a system exactly like grafts should be implemented, or whether it should be something more suited to Nix that is inspired by grafts, I can't say. But a system for small patches without rebuilding the entire tree is needed. Even if it can be technically incorrect package-wise, it will reach eventual consistency. (Plus users can opt-out and mass rebuild to their heart's content.)

mschwaig commented 1 month ago

As others have pointed out, we have functions with similar but not the same semantics, and these kind of mechanisms are useful, but also a bit hacky. It's definitively a topic where we should look at all the options.

One option to consider is more cleanly separating build-time and runtime-dependencies, as suggested here: https://github.com/NixOS/nix/issues/1080.

PS: I am a big fan of the Build Systems à la Carte paper linked in that article you posted as well.