nixVersions.git: Reintroduce

It was removed in 68472b90a6 because it
was out of date, using the old build system. Now, it is up to date, and
uses the Meson build system and the per-component build.

I am especially keen to get this is because once 2.28 uses the
monolithic build (#393509) out of an abundance of caution, this is will
be the only use of the per-component build, until the next Nix version
(and Nix 2.28 on master after Nixpkgs 25.05 is forked off and released).

pkgs/by-name/ni/nix-plugin-pijul/package.nix

@@ -81,6 +81,7 @@ stdenv.mkDerivation (finalAttrs: {
     {
       stable = localRepoCheck nixVersions.stable;
       latest = localRepoCheck nixVersions.latest;
+      git = localRepoCheck nixVersions.git;
       nix_2_24 = localRepoCheck nixVersions.nix_2_24;
     };
 

pkgs/tools/package-management/nix/default.nix

@@ -197,6 +197,20 @@ lib.makeExtensible (
 
       nix_2_28 = addTests "nix_2_28" self.nixComponents_2_28.nix-everything;
 
+      nixComponents_git = nixDependencies.callPackage ./modular/packages.nix rec {
+        version = "2.29pre20250407_${lib.substring 0 8 src.rev}";
+        inherit (self.nix_2_24.meta) maintainers;
+        otherSplices = generateSplicesForNixComponents "nixComponents_git";
+        src = fetchFromGitHub {
+          owner = "NixOS";
+          repo = "nix";
+          rev = "73d3159ba0b4b711c1f124a587f16e2486d685d7";
+          hash = "sha256-9wJXUGqXIqMjNyKWJKCcxrDHM/KxDkvJMwo6S3s+WuM=";
+        };
+      };
+
+      git = addTests "git" self.nixComponents_git.nix-everything;
+
       latest = self.nix_2_28;
 
       # The minimum Nix version supported by Nixpkgs
@@ -234,7 +248,6 @@ lib.makeExtensible (
         nix_2_27 = throw "nix_2_27 has been removed. use nix_2_28.";
 
         unstable = throw "nixVersions.unstable has been removed. use nixVersions.latest or the nix flake.";
-        git = throw "nixVersions.git has been removed. use nixVersions.latest or the nix flake.";
       }
     )
   )

pkgs/tools/package-management/nix/update-all.sh

@@ -36,3 +36,9 @@ for name in $nix_versions; do
         break
     fi
 done
+
+commit_json=$(curl -s https://api.github.com/repos/NixOS/nix/commits/master) # format: 2024-11-01T10:18:53Z
+date_of_commit=$(echo "$commit_json" | jq -r '.commit.author.date')
+suffix="pre$(date -d "$date_of_commit" +%Y%m%d)_"
+sed -i -e "s|\"pre[0-9]\{8\}_|\"$suffix|g" "$SCRIPT_DIR/default.nix"
+nix-update --override-filename "$SCRIPT_DIR/default.nix" --version branch --build --commit "nixVersions.git"

pkgs/top-level/release-cross.nix

@@ -79,6 +79,7 @@ let
     gmp = nativePlatforms;
     libcCross = nativePlatforms;
     nix = nativePlatforms;
+    nixVersions.git = nativePlatforms;
     mesa = nativePlatforms;
     rustc = nativePlatforms;
     cargo = nativePlatforms;