tests: avoid copying .git into the store

pkgs/test/release/default.nix

@@ -15,6 +15,19 @@ pkgs.runCommand "all-attrs-eval-under-tryEval" {
     pkgs.gitMinimal
   ] ++ lib.optional pkgs.stdenv.isLinux pkgs.inotify-tools;
   strictDeps = true;
+
+  src = with lib.fileset; toSource {
+    root = pkgs-path;
+    fileset = unions [
+      ./default.nix
+      ./doc
+      ./lib
+      ./maintainers
+      ./nixos
+      ./pkgs
+      ./.version
+    ];
+  };
 }
 ''
   datadir="${nix}/share"
@@ -31,15 +44,8 @@ pkgs.runCommand "all-attrs-eval-under-tryEval" {
 
   nix-store --init
 
-  cp -r ${pkgs-path}/lib lib
-  cp -r ${pkgs-path}/pkgs pkgs
-  cp -r ${pkgs-path}/default.nix default.nix
-  cp -r ${pkgs-path}/nixos nixos
-  cp -r ${pkgs-path}/maintainers maintainers
-  cp -r ${pkgs-path}/.version .version
-  cp -r ${pkgs-path}/doc doc
   echo "Running pkgs/top-level/release-attrpaths-superset.nix"
-  nix-instantiate --eval --strict --json pkgs/top-level/release-attrpaths-superset.nix -A names > /dev/null
+  nix-instantiate --eval --strict --json $src/pkgs/top-level/release-attrpaths-superset.nix -A names > /dev/null
 
   mkdir $out
   echo success > $out/${nix.version}