Release 3.22.3 (2026-09-02)

• Based on upstream Nix 2.35.2.

Parallel evaluation performance improvements

We’re continuing to make performance improvements to parallel evaluation, in particular reducing contention on the Boehm-Demers-Weiser garbage collector’s global lock by making more use of per-thread freelists and by removing the use of uncollectable allocations in builtins.fromJSON.

PRs: DeterminateSystems/nix-src#608, DeterminateSystems/nix-src#609

Miscellaneous changes

• Update Nixpkgs by @edolstra in DeterminateSystems/nix-src#607
• doc: mention that flake metadata’s Path field is absent with lazy-trees by @edolstra in DeterminateSystems/nix-src#620

Bug fixes

• Fix dir attribute handling in nix-219-compat mode by @edolstra in DeterminateSystems/nix-src#604
• Update the schema file atomically by @edolstra in DeterminateSystems/nix-src#606
• nix copy: Don’t register temp roots if the remote doesn’t have AddTempRoots by @edolstra in DeterminateSystems/nix-src#610
• Fix crash when GC is interrupted by @edolstra in DeterminateSystems/nix-src#612
• Handle out-of-memory crashes better by @edolstra in DeterminateSystems/nix-src#603
• Fix forwarding netrc-file to the daemon by @edolstra in DeterminateSystems/nix-src#616
• Sync with upstream 2.35-maintenance by @edolstra in DeterminateSystems/nix-src#617
• Fix Ctrl-C handling when Sentry is enabled by @edolstra in DeterminateSystems/nix-src#618
• Eval cache: make the second evaluation hit the cache by @roberth in DeterminateSystems/nix-src#619
• Deduplicate nix build --print-out-paths output by @edolstra in DeterminateSystems/nix-src#622

Full Changelog: v3.22.2…v3.22.3