Release notes for Nix 2.31

doc/manual/source/SUMMARY.md.in

@@ -138,6 +138,7 @@
   - [Contributing](development/contributing.md)
 - [Releases](release-notes/index.md)
 {{#include ./SUMMARY-rl-next.md}}
+  - [Release 2.31 (2025-08-21)](release-notes/rl-2.31.md)
   - [Release 2.30 (2025-07-07)](release-notes/rl-2.30.md)
   - [Release 2.29 (2025-05-14)](release-notes/rl-2.29.md)
   - [Release 2.28 (2025-04-02)](release-notes/rl-2.28.md)

doc/manual/source/release-notes/rl-2.31.md

@@ -0,0 +1,96 @@
+# Release 2.31.0 (2025-08-21)
+
+- `build-cores = 0` now auto-detects CPU cores [#13402](https://github.com/NixOS/nix/pull/13402)
+
+  When `build-cores` is set to `0`, Nix now automatically detects the number of available CPU cores and passes this value via `NIX_BUILD_CORES`, instead of passing `0` directly. This matches the behavior when `build-cores` is unset. This prevents the builder from having to detect the number of cores.
+
+- Fix Git LFS SSH issues [#13337](https://github.com/NixOS/nix/issues/13337) [#13743](https://github.com/NixOS/nix/pull/13743)
+
+  Fixed some outstanding issues with Git LFS and SSH.
+
+  * Added support for `NIX_SSHOPTS`.
+  * Properly use the parsed port from URL.
+  * Better use of the response of `git-lfs-authenticate` to determine API endpoint when the API is not exposed on port 443.
+
+- Add support for `user@address:port` syntax in store URIs [#7044](https://github.com/NixOS/nix/issues/7044) [#3425](https://github.com/NixOS/nix/pull/3425)
+
+  It's now possible to specify the port used for SSH stores directly in the store URL in accordance with [RFC3986](https://datatracker.ietf.org/doc/html/rfc3986). Previously the only way to specify custom ports was via `ssh_config` or the `NIX_SSHOPTS` environment variable, because Nix incorrectly passed the port number together with the host name to the SSH executable.
+
+  This change affects [store references](@docroot@/store/types/index.md#store-url-format) passed via the `--store` and similar flags in CLI as well as in the configuration for [remote builders](@docroot@/command-ref/conf-file.md#conf-builders). For example, the following store URIs now work:
+
+  - `ssh://127.0.0.1:2222`
+  - `ssh://[b573:6a48:e224:840b:6007:6275:f8f7:ebf3]:22`
+  - `ssh-ng://[b573:6a48:e224:840b:6007:6275:f8f7:ebf3]:22`
+
+- Represent IPv6 RFC4007 ZoneId literals in conformance with RFC6874 [#13445](https://github.com/NixOS/nix/pull/13445)
+
+  Prior versions of Nix since [#4646](https://github.com/NixOS/nix/pull/4646) accepted [IPv6 scoped addresses](https://datatracker.ietf.org/doc/html/rfc4007) in URIs like [store references](@docroot@/store/types/index.md#store-url-format) in the textual representation with a literal percent character: `[fe80::1%18]`. This was ambiguous, because the the percent literal `%` is reserved by [RFC3986](https://datatracker.ietf.org/doc/html/rfc3986), since it's used to indicate percent encoding. Nix now requires that the percent `%` symbol is percent-encoded as `%25`. This implements [RFC6874](https://datatracker.ietf.org/doc/html/rfc6874), which defines the representation of zone identifiers in URIs. The example from above now has to be specified as `[fe80::1%2518]`.
+
+- Use WAL mode for SQLite cache databases [#13800](https://github.com/NixOS/nix/pull/13800)
+
+  Previously, Nix used SQLite's "truncate" mode for caches. However, this could cause a Nix process to block if another process was updating the cache. This was a problem for the flake evaluation cache in particular, since it uses long-running transactions. Thus, concurrent Nix commands operating on the same flake could be blocked for an unbounded amount of time. WAL mode avoids this problem.
+
+  This change required updating the versions of the SQLite caches. For instance, `eval-cache-v5.sqlite` is now `eval-cache-v6.sqlite`.
+
+- Enable parallel marking in bdwgc [#13708](https://github.com/NixOS/nix/pull/13708)
+
+  Previously marking was done by only one thread, which takes a long time if the heap gets big. Enabling parallel marking speeds up evaluation a lot, for example (on a Ryzen 9 5900X 12-Core):
+
+  * `nix search nixpkgs` from 24.3s to 18.9s.
+  * Evaluating the `NixOS/nix/2.21.2` flake regression test from 86.1s to 71.2s.
+
+- New command `nix flake prefetch-inputs` [#13565](https://github.com/NixOS/nix/pull/13565)
+
+  This command fetches all inputs of a flake in parallel. This can be a lot faster than the serialized on-demand fetching during regular flake evaluation. The downside is that it may fetch inputs that aren't normally used.
+
+- Add `warn-short-path-literals` setting [#13489](https://github.com/NixOS/nix/pull/13489)
+
+  This setting, when enabled, causes Nix to emit warnings when encountering relative path literals that don't start with `.` or `/`, for instance suggesting that `foo/bar` should be rewritten to `./foo/bar`.
+
+- When updating a lock, respect the input's lock file [#13437](https://github.com/NixOS/nix/pull/13437)
+
+  For example, if a flake has a lock for `a` and `a/b`, and we change the flakeref for `a`, previously Nix would fetch the latest version of `b` rather than using the lock for `b` from `a`.
+
+- Implement support for Git hashing with SHA-256 [#13543](https://github.com/NixOS/nix/pull/13543)
+
+  The experimental support for [Git-hashing](@docroot@/development/experimental-features.md#xp-feature-git-hashing) store objects now also includes support for SHA-256, not just SHA-1, in line with upstream Git.
+
+## Contributors
+
+This release was made possible by the following 34 contributors:
+
+- John Soo [**(@jsoo1)**](https://github.com/jsoo1)
+- Alan Urmancheev [**(@alurm)**](https://github.com/alurm)
+- Manse [**(@PedroManse)**](https://github.com/PedroManse)
+- Pol Dellaiera [**(@drupol)**](https://github.com/drupol)
+- DavHau [**(@DavHau)**](https://github.com/DavHau)
+- Leandro Emmanuel Reina Kiperman [**(@kip93)**](https://github.com/kip93)
+- h0nIg [**(@h0nIg)**](https://github.com/h0nIg)
+- Philip Taron [**(@philiptaron)**](https://github.com/philiptaron)
+- Eelco Dolstra [**(@edolstra)**](https://github.com/edolstra)
+- Connor Baker [**(@ConnorBaker)**](https://github.com/ConnorBaker)
+- kenji [**(@a-kenji)**](https://github.com/a-kenji)
+- Oleksandr Knyshuk [**(@k1gen)**](https://github.com/k1gen)
+- Maciej Krüger [**(@mkg20001)**](https://github.com/mkg20001)
+- Justin Bailey [**(@jgbailey-well)**](https://github.com/jgbailey-well)
+- Emily [**(@emilazy)**](https://github.com/emilazy)
+- Volker Diels-Grabsch [**(@vog)**](https://github.com/vog)
+- gustavderdrache [**(@gustavderdrache)**](https://github.com/gustavderdrache)
+- Elliot Cameron [**(@de11n)**](https://github.com/de11n)
+- Alexander V. Nikolaev [**(@avnik)**](https://github.com/avnik)
+- tomberek [**(@tomberek)**](https://github.com/tomberek)
+- Matthew Kenigsberg [**(@mkenigs)**](https://github.com/mkenigs)
+- Sergei Zimmerman [**(@xokdvium)**](https://github.com/xokdvium)
+- Cosima Neidahl [**(@OPNA2608)**](https://github.com/OPNA2608)
+- John Ericson [**(@Ericson2314)**](https://github.com/Ericson2314)
+- m4dc4p [**(@m4dc4p)**](https://github.com/m4dc4p)
+- Graham Christensen [**(@grahamc)**](https://github.com/grahamc)
+- Jason Yundt [**(@Jayman2000)**](https://github.com/Jayman2000)
+- Jens Petersen [**(@juhp)**](https://github.com/juhp)
+- the-sun-will-rise-tomorrow [**(@the-sun-will-rise-tomorrow)**](https://github.com/the-sun-will-rise-tomorrow)
+- Farid Zakaria [**(@fzakaria)**](https://github.com/fzakaria)
+- AGawas [**(@aln730)**](https://github.com/aln730)
+- Robert Hensing [**(@roberth)**](https://github.com/roberth)
+- Dmitry Bogatov [**(@KAction)**](https://github.com/KAction)
+- Jörg Thalheim [**(@Mic92)**](https://github.com/Mic92)
+- Philipp Otterbein

maintainers/data/release-credits-email-to-handle.json

@@ -185,5 +185,23 @@
     "[email protected]": "gwennlbh",
     "[email protected]": "gwennlbh",
     "[email protected]": "MattSturgeon",
-    "[email protected]": "pbsds"
+    "[email protected]": "pbsds",
+    "[email protected]": "xokdvium",
+    "[email protected]": "vog",
+    "[email protected]": "PedroManse",
+    "[email protected]": "aln730",
+    "[email protected]": "mkg20001",
+    "[email protected]": "avnik",
+    "[email protected]": "k1gen",
+    "[email protected]": "alurm",
+    "[email protected]": "KAction",
+    "[email protected]": "juhp",
+    "[email protected]": "OPNA2608",
+    "[email protected]": "m4dc4p",
+    "[email protected]": "jgbailey-well",
+    "[email protected]": "de11n",
+    "[email protected]": "ConnorBaker",
+    "[email protected]": "jsoo1",
+    "[email protected]": "DavHau",
+    "[email protected]": "mkenigs"
 }

maintainers/data/release-credits-handle-to-name.json

@@ -162,5 +162,20 @@
     "pbsds": "Peder Bergebakken Sundt",
     "egorkonovalov": "Egor Konovalov",
     "jayeshv": "jayeshv",
-    "vcunat": "Vladim\u00edr \u010cun\u00e1t"
+    "vcunat": "Vladim\u00edr \u010cun\u00e1t",
+    "mkenigs": "Matthew Kenigsberg",
+    "alurm": "Alan Urmancheev",
+    "jgbailey-well": "Justin Bailey",
+    "k1gen": "Oleksandr Knyshuk",
+    "juhp": "Jens Petersen",
+    "de11n": "Elliot Cameron",
+    "jsoo1": "John Soo",
+    "m4dc4p": null,
+    "PedroManse": "Manse",
+    "OPNA2608": "Cosima Neidahl",
+    "mkg20001": "Maciej Kr\u00fcger",
+    "avnik": "Alexander V. Nikolaev",
+    "DavHau": null,
+    "aln730": "AGawas",
+    "vog": "Volker Diels-Grabsch"
 }

maintainers/release-process.md

@@ -29,6 +29,7 @@ release:
   ```console
   $ export VERSION=X.YY
   $ git checkout -b release-notes
+  $ export GITHUB_TOKEN=...
   $ ./maintainers/release-notes
   ```