Use auto-uid-allocate

Fix action to make it work on custom containers;

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-20.03
+        nix_path: nixpkgs=channel:nixos-22.11
     - run: nix-env -iA cachix -f https://cachix.org/api/v1/install
     - run: cat /etc/nix/nix.conf
     # cachix should be available and be able to configure a cache
@@ -46,7 +46,7 @@ jobs:
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-20.03
+        nix_path: nixpkgs=channel:nixos-22.11
         extra_nix_config: |
           sandbox = relaxed
     - run: cat /etc/nix/nix.conf
@@ -73,7 +73,7 @@ jobs:
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.05
+        nix_path: nixpkgs=channel:nixos-22.11
         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
     - run: nix-build test.nix
@@ -88,7 +88,7 @@ jobs:
     - name: Install Nix
       uses: ./
       with:
-        nix_path: nixpkgs=channel:nixos-22.05
+        nix_path: nixpkgs=channel:nixos-22.11
         install_url: https://releases.nixos.org/nix/nix-2.8.0/install
     - run: nix-build test.nix
 

action.yml

@@ -18,7 +18,7 @@ branding:
 runs:
   using: 'composite'
   steps:
-    - run : ${{ github.action_path }}/install-nix.sh
+    - run : ${GITHUB_ACTION_PATH}/install-nix.sh
       shell: bash
       env:
         INPUT_EXTRA_NIX_CONFIG: ${{ inputs.extra_nix_config }}

install-nix.sh

@@ -32,7 +32,7 @@ if [[ -n "${INPUT_EXTRA_NIX_CONFIG:-}" ]]; then
   add_config "$INPUT_EXTRA_NIX_CONFIG"
 fi
 if [[ ! $INPUT_EXTRA_NIX_CONFIG =~ "experimental-features" ]]; then
-  add_config "experimental-features = nix-command flakes"
+  add_config "experimental-features = nix-command flakes auto-allocate-uids"
 fi
 
 # Nix installer flags
@@ -46,8 +46,9 @@ installer_options=(
 if [[ (! $INPUT_INSTALL_OPTIONS =~ "--no-daemon") && ($OSTYPE =~ darwin || -e /run/systemd/system) ]]; then
   installer_options+=(
     --daemon
-    --daemon-user-count "$(python3 -c 'import multiprocessing as mp; print(mp.cpu_count() * 2)')"
+    --daemon-user-count 1
   )
+  add_config "auto-allocate-uids = true"
 else
   # "fix" the following error when running nix*
   # error: the group 'nixbld' specified in 'build-users-group' does not exist
@@ -66,7 +67,7 @@ echo "installer options: ${installer_options[*]}"
 
 # There is --retry-on-errors, but only newer curl versions support that
 curl_retries=5
-while ! curl -sS -o "$workdir/install" -v --fail -L "${INPUT_INSTALL_URL:-https://nixos.org/nix/install}"
+while ! curl -sS -o "$workdir/install" -v --fail -L "${INPUT_INSTALL_URL:-https://releases.nixos.org/nix/nix-2.15.1/install}"
 do
   sleep 1
   ((curl_retries--))