DeterminateSystems · detsys-spaghetti · Dec 19, 2025 · Dec 19, 2025 · Dec 19, 2025 · Dec 19, 2025
diff --git a/.version-determinate b/.version-determinate
@@ -1 +1 @@
-3.14.0
+3.15.0
diff --git a/doc/manual/source/SUMMARY.md.in b/doc/manual/source/SUMMARY.md.in
@@ -144,6 +144,7 @@
   - [Contributing](development/contributing.md)
 - [Determinate Nix Release Notes](release-notes-determinate/index.md)
   - [Changes between Nix and Determinate Nix](release-notes-determinate/changes.md)<!-- next -->
+  - [Release 3.15.0 (2025-12-19)](release-notes-determinate/v3.15.0.md)
   - [Release 3.14.0 (2025-12-08)](release-notes-determinate/v3.14.0.md)
   - [Release 3.13.2 (2025-11-19)](release-notes-determinate/v3.13.2.md)
   - [Release 3.13.1 (2025-11-12)](release-notes-determinate/v3.13.1.md)

diff --git a/doc/manual/source/release-notes-determinate/changes.md b/doc/manual/source/release-notes-determinate/changes.md
@@ -1,6 +1,6 @@
 # Changes between Nix and Determinate Nix
 
-This section lists the differences between upstream Nix 2.32 and Determinate Nix 3.14.0.<!-- differences -->
+This section lists the differences between upstream Nix 2.33 and Determinate Nix 3.15.0.<!-- differences -->
 
 * In Determinate Nix, flakes are stable. You no longer need to enable the `flakes` experimental feature.
 
@@ -22,9 +22,9 @@ This section lists the differences between upstream Nix 2.32 and Determinate Nix
 
 <!-- Determinate Nix version 3.5.1 -->
 
-* `nix upgrade-nix` is now inert, and suggests using `determinate-nixd upgrade` -- [DeterminateSystems/nix-src#55](https://github.com/DeterminateSystems/nix-src/pull/55)
+* `nix upgrade-nix` is now inert, and suggests using `determinate-nixd upgrade`. [DeterminateSystems/nix-src#55](https://github.com/DeterminateSystems/nix-src/pull/55)
 
-* Lazy Trees support has been merged. ([DeterminateSystems/nix-src#27](https://github.com/DeterminateSystems/nix-src/pull/27), [DeterminateSystems/nix-src#56](https://github.com/DeterminateSystems/nix-src/pull/56))
+* Determinate Nix has Lazy Trees, avoiding expensive copying of flake inputs to the Nix store. ([DeterminateSystems/nix-src#27](https://github.com/DeterminateSystems/nix-src/pull/27), [DeterminateSystems/nix-src#56](https://github.com/DeterminateSystems/nix-src/pull/56))
 
 <!-- Determinate Nix version 3.5.2 -->
 
@@ -34,40 +34,29 @@ This section lists the differences between upstream Nix 2.32 and Determinate Nix
 
 <!-- Determinate Nix version 3.6.2 -->
 
-* Faster `nix store copy-sigs` by @edolstra in [DeterminateSystems/nix-src#80](https://github.com/DeterminateSystems/nix-src/pull/80)
+* Documentation on how to replicate `nix-store --query --deriver` with the new `nix` cli. [DeterminateSystems/nix-src#82](https://github.com/DeterminateSystems/nix-src/pull/82)
 
-* Document how to replicate nix-store --query --deriver with the nix cli by @grahamc in [DeterminateSystems/nix-src#82](https://github.com/DeterminateSystems/nix-src/pull/82)
+* In `nix profile`, the symbols `ε` and `∅` have been replaced with descriptive English words. [DeterminateSystems/nix-src#81](https://github.com/DeterminateSystems/nix-src/pull/81)
 
-* nix profile: Replace ε and ∅ with descriptive English words by @grahamc in [DeterminateSystems/nix-src#81](https://github.com/DeterminateSystems/nix-src/pull/81)
-
-* Call out that `--keep-failed` with remote builders will keep the failed build directory on that builder by @cole-h in [DeterminateSystems/nix-src#85](https://github.com/DeterminateSystems/nix-src/pull/85)
 <!-- Determinate Nix version 3.6.3 revoked -->
 
 <!-- Determinate Nix version 3.6.4 revoked -->
 
 <!-- Determinate Nix version 3.6.5 -->
 
-* When remote building with --keep-failed, only show "you can rerun" message if the derivation's platform is supported on this machine by @cole-h in [DeterminateSystems/nix-src#87](https://github.com/DeterminateSystems/nix-src/pull/87)
-
-* Indicate that sandbox-paths specifies a missing file in the corresponding error message. by @cole-h in [DeterminateSystems/nix-src#88](https://github.com/DeterminateSystems/nix-src/pull/88)
-
-* Use FlakeHub inputs by @lucperkins in [DeterminateSystems/nix-src#89](https://github.com/DeterminateSystems/nix-src/pull/89)
+* When remote building with `--keep-failed`, Determinate Nix shows "you can rerun" message if the derivation's platform is supported on this machine. [DeterminateSystems/nix-src#87](https://github.com/DeterminateSystems/nix-src/pull/87)
 
-* Proactively cache more flake inputs and fetches by @edolstra in [DeterminateSystems/nix-src#93](https://github.com/DeterminateSystems/nix-src/pull/93)
-
-* Improve caching of inputs in dry-run mode by @edolstra in [DeterminateSystems/nix-src#98](https://github.com/DeterminateSystems/nix-src/pull/98)
+* Improved error message when `sandbox-paths` specifies a missing file. [DeterminateSystems/nix-src#88](https://github.com/DeterminateSystems/nix-src/pull/88)
 
 <!-- Determinate Nix version 3.6.6 -->
 
 <!-- Determinate Nix version 3.6.7 -->
 
 <!-- Determinate Nix version 3.6.8 -->
 
-* Add lazy-locks setting by @edolstra in [DeterminateSystems/nix-src#113](https://github.com/DeterminateSystems/nix-src/pull/113)
-
 <!-- Determinate Nix version 3.7.0 -->
 
-* `nix store delete` now explains why deletion fails by @edolstra in [DeterminateSystems/nix-src#130](https://github.com/DeterminateSystems/nix-src/pull/130)
+* `nix store delete` now explains why deletion fails. [DeterminateSystems/nix-src#130](https://github.com/DeterminateSystems/nix-src/pull/130)
 
 <!-- Determinate Nix version 3.8.0 -->
 
@@ -81,21 +70,21 @@ This section lists the differences between upstream Nix 2.32 and Determinate Nix
 
 <!-- Determinate Nix version 3.8.5 -->
 
-* Tab completing arguments to Nix avoids network access [DeterminateSystems/nix-src#161](https://github.com/DeterminateSystems/nix-src/pull/161)
+* Tab completing arguments to Nix avoids network access. [DeterminateSystems/nix-src#161](https://github.com/DeterminateSystems/nix-src/pull/161)
 
-* Importing Nixpkgs and other tarballs to the cache is 2-4x faster [DeterminateSystems/nix-src#149](https://github.com/DeterminateSystems/nix-src/pull/149)
+* Importing Nixpkgs and other tarballs to the cache is 2-4x faster. [DeterminateSystems/nix-src#149](https://github.com/DeterminateSystems/nix-src/pull/149)
 
-* Adding paths to the store is significantly faster [DeterminateSystems/nix-src#162](https://github.com/DeterminateSystems/nix-src/pull/162)
+* Adding paths to the store is significantly faster. [DeterminateSystems/nix-src#162](https://github.com/DeterminateSystems/nix-src/pull/162)
 
 <!-- Determinate Nix version 3.8.6 -->
 
 <!-- Determinate Nix version 3.9.0 -->
 
-* Build-time flake inputs [DeterminateSystems/nix-src#49](https://github.com/DeterminateSystems/nix-src/pull/49)
+* Determinate Nix allows flake inputs to be fetched at build time. [DeterminateSystems/nix-src#49](https://github.com/DeterminateSystems/nix-src/pull/49)
 
 <!-- Determinate Nix version 3.9.1 -->
 
-* The default `nix flake init` template is much more useful [DeterminateSystems/nix-src#180](https://github.com/DeterminateSystems/nix-src/pull/180)
+* The default `nix flake init` template is much more useful. [DeterminateSystems/nix-src#180](https://github.com/DeterminateSystems/nix-src/pull/180)
 
 <!-- Determinate Nix version 3.10.0 -->
 
@@ -104,26 +93,21 @@ This section lists the differences between upstream Nix 2.32 and Determinate Nix
 
 <!-- Determinate Nix version 3.11.0 -->
 
-* Multithreaded evaluation support [DeterminateSystems/nix-src#125](https://github.com/DeterminateSystems/nix-src/pull/125)
+* Multithreaded evaluation support. [DeterminateSystems/nix-src#125](https://github.com/DeterminateSystems/nix-src/pull/125)
 
 <!-- Determinate Nix version 3.11.1 -->
 
 
 <!-- Determinate Nix version 3.11.2 -->
 
-* Fix some interactions with the registry and flakes that include a `?dir=` parameter [DeterminateSystems/nix-src#196](https://github.com/DeterminateSystems/nix-src/pull/196), [DeterminateSystems/nix-src#199](https://github.com/DeterminateSystems/nix-src/pull/199)
-
-* Only try to substitute input if fetching from its original location fails [DeterminateSystems/nix-src#202](https://github.com/DeterminateSystems/nix-src/pull/202)
+* Determinate Nix only tries to substitute inputs if fetching from its original location fails.[DeterminateSystems/nix-src#202](https://github.com/DeterminateSystems/nix-src/pull/202)
 
 <!-- Determinate Nix version 3.11.3 -->
 
 
 <!-- Determinate Nix version 3.12.0 -->
 
-* `nix flake clone` supports arbitrary input types. [DeterminateSystems/nix-src#229](https://github.com/DeterminateSystems/nix-src/pull/229)
-
-* A new command `nix nario` that replaces `nix-store --export|--export`. It also has a new file format (`--format 2`) that supports store path attributes such as signatures, and that can be imported more efficiently.
-[DeterminateSystems/nix-src#215](https://github.com/DeterminateSystems/nix-src/pull/215)
+* A new command `nix nario` that replaces `nix-store --export|--export`. It also has a new file format (`--format 2`) that supports store path attributes such as signatures, and that can be imported more efficiently. [DeterminateSystems/nix-src#215](https://github.com/DeterminateSystems/nix-src/pull/215)
 
 * Determinate Nix prints the Nix version when using `-vv` or higher verbosity. [DeterminateSystems/nix-src#237](https://github.com/DeterminateSystems/nix-src/pull/237)
 
@@ -134,37 +118,33 @@ This section lists the differences between upstream Nix 2.32 and Determinate Nix
 
 <!-- Determinate Nix version 3.12.2 -->
 
-* Computing the `revCount` attribute is multi-threaded, making it much faster for repositories like Nixpkgs. [DeterminateSystems/nix-src#245](https://github.com/DeterminateSystems/nix-src/pull/245)
-
-* Flakerefs in error messages are abbreviated for readability. [DeterminateSystems/nix-src#243](https://github.com/DeterminateSystems/nix-src/pull/243)
+* Flakerefs in error messages and lockfile diffs are abbreviated for readability. [DeterminateSystems/nix-src#243](https://github.com/DeterminateSystems/nix-src/pull/243),  [DeterminateSystems/nix-src#264](https://github.com/DeterminateSystems/nix-src/pull/264)
 
 <!-- Determinate Nix version 3.13.0 -->
 
-* Git fetching has a progress indication [DeterminateSystems/nix-src#250](https://github.com/DeterminateSystems/nix-src/pull/250)
-
 <!-- Determinate Nix version 3.13.1 -->
 
 
 <!-- Determinate Nix version 3.13.2 -->
 
-* Abbreviate flakerefs in lockfile diffs and `nix flake metadata` [DeterminateSystems/nix-src#264](https://github.com/DeterminateSystems/nix-src/pull/264)
+* The Git fetcher doesn't compute `revCount` or `lastModified` if they're already specified [DeterminateSystems./nix-src#269](https://github.com/DeterminateSystems/nix-src/pull/269)
 
-* nix flake prefetch-inputs: Skip build-time inputs [DeterminateSystems/nix-src#263](https://github.com/DeterminateSystems/nix-src/pull/263)
+* The Git fetcher avoids doing a shallow Git fetch if it previously did a non-shallow fetch of the same repository. [DeterminateSystems/nix-src#270](https://github.com/DeterminateSystems/nix-src/pull/270)
 
-* Git fetcher: Don't compute revCount/lastModified if they're already specified [DeterminateSystems/nix-src#269](https://github.com/DeterminateSystems/nix-src/pull/269)
+* Determinate Nix has a builtin copy of the flake registry, making it more resilient to network outages. [DeterminateSystems/nix-src#271](https://github.com/DeterminateSystems/nix-src/pull/271)
 
-* Avoid unnecessary Git refetches [DeterminateSystems/nix-src#270](https://github.com/DeterminateSystems/nix-src/pull/270)
+<!-- Determinate Nix version 3.14.0 -->
 
-* Use mirrored flake registry [DeterminateSystems/nix-src#271](https://github.com/DeterminateSystems/nix-src/pull/271)
+* `nix build` and `nix profile` report failing or succeeding installables. [DeterminateSystems/nix-src#281](https://github.com/DeterminateSystems/nix-src/pull/281)
 
-<!-- Determinate Nix version 3.14.0 -->
+* `nix flake check` shows which outputs failed or succeeded. [DeterminateSystems/nix-src#285](https://github.com/DeterminateSystems/nix-src/pull/285)
 
-* Fixed a builtins.path regression: Propagate references from derivation outputs [DeterminateSystems/nix-src#283](https://github.com/DeterminateSystems/nix-src/pull/283)
+* Determinate Nix has a `nix ps` command to show active builds. [DeterminateSystems/nix-src#282](https://github.com/DeterminateSystems/nix-src/pull/282)
 
-* nix build, nix profile: Report failing/succeeding installables [DeterminateSystems/nix-src#281](https://github.com/DeterminateSystems/nix-src/pull/281)
+* Determinate Nix has improved backward compatibility with lock files created by Nix < 2.20. [DeterminateSystems/nix-src#278](https://github.com/DeterminateSystems/nix-src/pull/278)
 
-* nix flake check: Show which outputs failed or succeeded [DeterminateSystems/nix-src#285](https://github.com/DeterminateSystems/nix-src/pull/285)
+<!-- Determinate Nix version 3.15.0 -->
 
-* Add `nix ps` command [DeterminateSystems/nix-src#282](https://github.com/DeterminateSystems/nix-src/pull/282)
+* Determinate Nix has a builtin function `builtins.filterAttrs`. [DeterminateSystems/nix-src#291](https://github.com/DeterminateSystems/nix-src/pull/291)
 
-* Backward compatibility for Nix < 2.20: Git inputs using git-archive [DeterminateSystems/nix-src#278](https://github.com/DeterminateSystems/nix-src/pull/278)
+* `builtins.fetchTree` implicitly sets `__final = true` when a `narHash` is supplied. This allows the tree to be substituted. [DeterminateSystems/nix-src#297](https://github.com/DeterminateSystems/nix-src/pull/297)
diff --git a/doc/manual/source/release-notes-determinate/v3.15.0.md b/doc/manual/source/release-notes-determinate/v3.15.0.md
@@ -0,0 +1,28 @@
+# Release 3.15.0 (2025-12-19)
+
+* Based on [upstream Nix 2.33.0](../release-notes/rl-2.33.md).
+
+## `fetchTree` improvement
+
+`builtins.fetchTree` now implicitly treats the fetched tree as "final" when a `narHash` is supplied, meaning that it will not return attributes like `lastModified` or `revCount` unless they were specified by the caller. This makes it possible to substitute the tree from a binary cache, which is often more efficient. Furthermore, for Git inputs, it allows Nix to perform a shallow fetch, which is much faster.
+
+This is primarily useful for users of `flake-compat`, since it uses `builtins.fetchTree` internally.
+
+PR: [DeterminateSystems/nix-src#297](https://github.com/DeterminateSystems/nix-src/pull/297)
+
+## New builtin function `builtins.filterAttrs`
+
+Nixpkgs heavily relies on this function to select attributes from an attribute set:
+
+```nix
+filterAttrs = pred: set: removeAttrs set (filter (name: !pred name set.${name}) (attrNames set));
+```
+
+Determinate Nix now has this function built-in, which makes it much faster.
+
+PR: [DeterminateSystems/nix-src#291](https://github.com/DeterminateSystems/nix-src/pull/291)
+
+## New Contributors
+* @not-ronjinger made their first contribution in [DeterminateSystems/nix-src#291](https://github.com/DeterminateSystems/nix-src/pull/291)
+
+**Full Changelog**: [v3.14.0...v3.15.0](https://github.com/DeterminateSystems/nix-src/compare/v3.14.0...v3.15.0)