2024-03-04 Nix team meeting minutes #130


remote instantiation (`NIX_REMOTE`, `--store`) is an order of magnitude slower than local instantiation + `nix copy` · Issue #10119 · NixOS/nix · GitHub

How do we prevent this thing from happening?

  • @eelco: Construct the derivation graph in memory and stream the whole result to the store?
    • Also would solve the issues with read-only mode
    • Not a perfect fix because only works for drv files, but already covers the bulk of the problem
  • Could also make eval-store an option
  • Maybe also separate build-store
  • In-memory eval store could be either an overlay store or a normal store

`fetchTree` performs fetch even when a `narHash` is provided · Issue #10104 · NixOS/nix · GitHub

Assigned to @edolstra

  • @roberth: The fetch cache is quite confusing, stores a whole bunch of different stuff, no schema
  • @edolstra: It’s a very generic KV store, makes the implementation much easier
  • @roberth: Might be hiding bugs, might want to be a bit stricter
  • @roberth: Maybe have a set of methods (of the same form) that make clear what’s the purpose of each “virtual table”
    • make sure to separate “pure” caching and “impure” caching

Installer bootstrapping issue due to nix 2.20.3 missing from nixpkgs · Issue #10109 · NixOS/nix · GitHub

  • @thufschmitt: Any way we could avoid that in the future?
  • @edolstra: In that instance, had to change an element from an array to an object, so hard to do in a forward-compatible way
  • @roberth: Could have kept both the object and the array under different names, and have the new version be able to handle both
  • For that, might jq a backwards migration script, although would be tricky to get Nix to rebuild a profile with all the right things

@thufschmitt will add a comment near the version field to warn people who’ll want to change it in the future.

Fix `__darwinAllowLocalNetworking` sandbox by szlend · Pull Request #10078 · NixOS/nix · GitHub


refactor: move the repl input code to its own file by lf- · Pull Request #10083 · NixOS/nix · GitHub

Looks good in theory, needs careful review

Assigned to @roberth


Assigned to @thufschmitt

Use SourcePath for reading flake.{nix,lock} by edolstra · Pull Request #10088 · NixOS/nix · GitHub

Suggestions by @Ericson2314, but can be a follow-up.

Improve support for subflakes by edolstra · Pull Request #10089 · NixOS/nix · GitHub

Makes subflakes actually usable.

  • @thufschmitt: Semantic changes?
    • @edolstra: Some things are more permissive. Like allowing subflakes to access the parent directory
    • @roberth: Too permissive?
    • Maybe should only allow that explicitly?
  • To discuss (and discussed below)

Ignore references when importing signatures by raboof · Pull Request #10101 · NixOS/nix · GitHub

improve error reports somewhat by pennae · Pull Request #9874 · NixOS/nix · GitHub

Assigned to @thufschmitt.
Will wait at least until after the release (early next week) to merge as it can be a disruptive change.

Forbid nested debuggers by 9999years · Pull Request #9920 · NixOS/nix · GitHub

Assigned to @thufschmitt, can merge once CI is green

feat: small-string optimization by tomberek · Pull Request #9895 · NixOS/nix · GitHub

Waiting for when Tom is back

Remove the stack overflow handler by edolstra · Pull Request #9878 · NixOS/nix · GitHub

Might be too early to remove it.
Not having it on Darwin is annoying

Could it be replaced by Instrumentation Options (Using the GNU Compiler Collection (GCC))?


Add nixos-unstable based outputs, bdwgc 8.2.4, Nixpkgs lib tests, cleanup by roberth · Pull Request #9900 · NixOS/nix · GitHub

Improve support for subflakes by edolstra · Pull Request #10089 · NixOS/nix · GitHub