don't insist $USER needs to be set

.github/workflows/test.yml

@@ -61,6 +61,11 @@ jobs:
     - uses: actions/checkout@v3
     - name: Install Nix
       uses: ./
+      with:
+        install_url: https://nixos-nix-install-tests.cachix.org/serve/i6laym9jw3wg9mw6ncyrk6gjx4l34vvx/install
+        install_options: '--tarball-url-prefix https://nixos-nix-install-tests.cachix.org/serve'
+        extra_nix_config: |
+          access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
     - run: nix flake show github:NixOS/nixpkgs
 
   installer-options:
@@ -73,9 +78,9 @@ jobs:
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.05
-        install_options: --tarball-url-prefix https://nixos-nix-install-tests.cachix.org/serve
-        install_url: https://nixos-nix-install-tests.cachix.org/serve/s62m7lc0q0mz2mxxm9q0kkrcg90njzhq/install
+        nix_path: nixpkgs=channel:nixos-21.05
+        install_url: https://nixos-nix-install-tests.cachix.org/serve/i6laym9jw3wg9mw6ncyrk6gjx4l34vvx/install
+        install_options: '--tarball-url-prefix https://nixos-nix-install-tests.cachix.org/serve'
     - run: nix-build test.nix
 
   oldest-supported-installer:
@@ -88,8 +93,8 @@ jobs:
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.05
-        install_url: https://releases.nixos.org/nix/nix-2.8.0/install
+        nix_path: nixpkgs=channel:nixos-21.05
+        install_url: https://releases.nixos.org/nix/nix-2.3.8/install
     - run: nix-build test.nix
 
   act-support:

install-nix.sh

@@ -20,7 +20,7 @@ add_config() {
 # Set jobs to number of cores
 add_config "max-jobs = auto"
 # Allow binary caches for user
-add_config "trusted-users = root $USER"
+add_config "trusted-users = root ${USER:-}"
 # Add github access token
 if [[ $INPUT_GITHUB_ACCESS_TOKEN != "" ]]; then
   add_config "access-tokens" "github.com=$INPUT_GITHUB_ACCESS_TOKEN"
@@ -86,7 +86,8 @@ fi
 
 # Set paths
 echo "/nix/var/nix/profiles/default/bin" >> "$GITHUB_PATH"
-echo "/nix/var/nix/profiles/per-user/$USER/profile/bin" >> "$GITHUB_PATH"
+# new path for nix 2.14
+echo "$HOME/.nix-profile/bin" >> "$GITHUB_PATH"
 
 if [[ $INPUT_NIX_PATH != "" ]]; then
   echo "NIX_PATH=${INPUT_NIX_PATH}" >> "$GITHUB_ENV"