Merge pull request #262 from cachix/dependabot/github_actions/actions/checkout-6

chore(deps): bump actions/checkout from 5 to 6

.github/workflows/test-per-system.yml

@@ -0,0 +1,98 @@
+name: Test Runner
+
+on:
+  workflow_call:
+    inputs:
+      runs-on:
+        description: 'GitHub Actions runner to use (e.g., ubuntu-latest, macos-latest)'
+        required: true
+        type: string
+      system:
+        description: 'Target system architecture (e.g., x86_64-linux, aarch64-darwin)'
+        required: true
+        type: string
+      oldest_installer_version:
+        description: 'Oldest supported Nix installer version to test (e.g., nix-2.8.0)'
+        required: false
+        default: 'nix-2.8.0'
+        type: string
+
+env:
+  nixpkgs_channel: nixpkgs=channel:nixos-25.05
+
+jobs:
+  simple-build:
+    runs-on: ${{ inputs.runs-on }}
+    steps:
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
+    - name: Install Nix
+      uses: ./
+      with:
+        nix_path: ${{ env.nixpkgs_channel }}
+    - name: Test environment variables
+      run: ./tests/test-env.sh
+    - 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
+    - run: cachix use cachix
+    - run: nix-build tests/test-build.nix
+
+  custom-nix-path:
+    runs-on: ${{ inputs.runs-on }}
+    steps:
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
+    - name: Install Nix
+      uses: ./
+      with:
+        nix_path: ${{ env.nixpkgs_channel }}
+    - run: test $NIX_PATH == '${{ env.nixpkgs_channel }}'
+    - run: nix-build tests/test-build.nix
+
+  extra-nix-config:
+    runs-on: ${{ inputs.runs-on }}
+    steps:
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
+    - name: Install Nix
+      uses: ./
+      with:
+        nix_path: ${{ env.nixpkgs_channel }}
+        extra_nix_config: |
+          sandbox = relaxed
+    - run: cat /etc/nix/nix.conf
+    - run: nix-build tests/test-build.nix --arg noChroot true
+
+  flakes:
+    runs-on: ${{ inputs.runs-on }}
+    steps:
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
+    - name: Install Nix
+      uses: ./
+    - run: nix flake show github:NixOS/nixpkgs
+
+  latest-installer:
+    runs-on: ${{ inputs.runs-on }}
+    steps:
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
+    - name: Run NAR server
+      run: |
+        curl --location https://github.com/cachix/nar-toolbox/releases/download/v0.1.0/nar-toolbox-${{ inputs.system }} -O
+        chmod +x ./nar-toolbox-${{ inputs.system }}
+        ./nar-toolbox-${{ inputs.system }} serve https://cache.nixos.org &
+    - name: Install Nix
+      uses: ./
+      with:
+        nix_path: ${{ env.nixpkgs_channel }}
+        install_url: https://hydra.nixos.org/job/nix/master/installerScript/latest-finished/download/1/install
+        install_options: "--tarball-url-prefix http://localhost:8080"
+    - run: nix-build tests/test-build.nix
+
+  oldest-supported-installer:
+    runs-on: ${{ inputs.runs-on }}
+    steps:
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
+    - name: Install Nix
+      uses: ./
+      with:
+        nix_path: ${{ env.nixpkgs_channel }}
+        install_url: https://releases.nixos.org/nix/${{ inputs.oldest_installer_version }}/install
+    - run: nix-build tests/test-build.nix

.github/workflows/test.yml

@@ -4,149 +4,62 @@ on:
   push:
     branches:
       - master
+  workflow_dispatch:
 
 env:
-  nixpkgs_channel: nixpkgs=channel:nixos-24.11
-  oldest_supported_installer: nix-2.8.0
+  nixpkgs_channel: nixpkgs=channel:nixos-25.05
 
 jobs:
-  simple-build:
-    strategy:
-      fail-fast: false
-      matrix:
-        os:
-        - ubuntu-latest
-        - ubuntu-24.04-arm
-        - macos-latest
-        - macos-13
-    runs-on: ${{ matrix.os }}
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Install Nix
-      uses: ./
-      with:
-        nix_path: ${{ env.nixpkgs_channel }}
-    - 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
-    - run: cachix use cachix
-    - run: nix-build test.nix
-
-  custom-nix-path:
-    strategy:
-      fail-fast: false
-      matrix:
-        os:
-        - ubuntu-latest
-        - ubuntu-24.04-arm
-        - macos-latest
-        - macos-13
-    runs-on: ${{ matrix.os }}
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Install Nix
-      uses: ./
-      with:
-        nix_path: ${{ env.nixpkgs_channel }}
-    - run: test $NIX_PATH == '${{ env.nixpkgs_channel }}'
-    - run: nix-build test.nix
-
-  extra-nix-config:
-    strategy:
-      fail-fast: false
-      matrix:
-        os:
-        - ubuntu-latest
-        - ubuntu-24.04-arm
-        - macos-latest
-        - macos-13
-    runs-on: ${{ matrix.os }}
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Install Nix
-      uses: ./
-      with:
-        nix_path: ${{ env.nixpkgs_channel }}
-        extra_nix_config: |
-          sandbox = relaxed
-    - run: cat /etc/nix/nix.conf
-    - run: nix-build test.nix --arg noChroot true
-
-  flakes:
-    strategy:
-      fail-fast: false
-      matrix:
-        os:
-        - ubuntu-latest
-        - ubuntu-24.04-arm
-        - macos-latest
-        - macos-13
-    runs-on: ${{ matrix.os }}
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Install Nix
-      uses: ./
-    - run: nix flake show github:NixOS/nixpkgs
-
-  latest-installer:
+  test:
     strategy:
       fail-fast: false
+      # For the list of available images:
+      #   GitHub images: https://github.com/actions/runner-images?tab=readme-ov-file#available-images
+      #   Partner images: https://github.com/actions/partner-runner-images?tab=readme-ov-file#available-images
       matrix:
         include:
-          - os: ubuntu-latest
+          - runs-on: ubuntu-latest
             system: x86_64-linux
-          - os: ubuntu-24.04-arm
+            oldest_installer_version: nix-2.8.0
+          - runs-on: ubuntu-22.04
+            system: x86_64-linux
+            oldest_installer_version: nix-2.8.0
+          - runs-on: ubuntu-24.04-arm
             system: aarch64-linux
-          - os: macos-latest
+            oldest_installer_version: nix-2.8.0
+          - runs-on: ubuntu-22.04-arm
+            system: aarch64-linux
+            oldest_installer_version: nix-2.8.0
+          - runs-on: macos-latest
             system: aarch64-darwin
-          - os: macos-13
+            oldest_installer_version: nix-2.18.6
+          - runs-on: macos-26
+            system: aarch64-darwin
+            oldest_installer_version: nix-2.18.6
+          - runs-on: macos-15
+            system: aarch64-darwin
+            oldest_installer_version: nix-2.18.6
+          - runs-on: macos-14
+            system: aarch64-darwin
+            oldest_installer_version: nix-2.8.0
+          - runs-on: macos-15-intel
             system: x86_64-darwin
-    runs-on: ${{ matrix.os }}
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Run NAR server
-      run: |
-        curl --location https://github.com/cachix/nar-toolbox/releases/download/v0.1.0/nar-toolbox-${{ matrix.system }} -O
-        chmod +x ./nar-toolbox-${{ matrix.system }}
-        ./nar-toolbox-${{ matrix.system }} serve https://cache.nixos.org &
-    - name: Install Nix
-      uses: ./
-      with:
-        nix_path: ${{ env.nixpkgs_channel }}
-        install_url: https://hydra.nixos.org/job/nix/master/installerScript/latest-finished/download/1/install
-        install_options: "--tarball-url-prefix http://localhost:8080"
-    - run: nix-build test.nix
-
-  oldest-supported-installer:
-    strategy:
-      fail-fast: false
-      matrix:
-        os:
-        - ubuntu-latest
-        - ubuntu-24.04-arm
-        - macos-latest
-        - macos-13
-    runs-on: ${{ matrix.os }}
-    steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-    - name: Install Nix
-      uses: ./
-      with:
-        nix_path: ${{ env.nixpkgs_channel }}
-        install_url: https://releases.nixos.org/nix/${{ env.oldest_supported_installer }}/install
-    - run: nix-build test.nix
+            oldest_installer_version: nix-2.18.6
+    uses: ./.github/workflows/test-per-system.yml
+    with:
+      runs-on: ${{ matrix.runs-on }}
+      system: ${{ matrix.system }}
+      oldest_installer_version: ${{ matrix.oldest_installer_version }}
 
   act-support:
-    strategy:
-      matrix:
-        os: [ubuntu-latest]
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - run: curl https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash
     - run: docker pull ghcr.io/catthehacker/ubuntu:js-24.04
     - run: |
         ./bin/act push \
           -P ubuntu-latest=ghcr.io/catthehacker/ubuntu:js-24.04 \
           -j simple-build \
-          --matrix os:ubuntu-latest
+          --matrix runs-on:ubuntu-latest \
+          --matrix system:x86_64-linux

.github/workflows/update-nix.yml

@@ -8,7 +8,7 @@ jobs:
   update-nix-releases:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Update nix releases
         env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
@@ -23,9 +23,30 @@ jobs:
             echo "Failed to determine latest Nix version." >&2
             exit 1
           fi
+          current_nix=$(grep -oE 'nix_version=[0-9.]+' ./install-nix.sh | cut -d= -f2)
+          echo "Current Nix version: ${current_nix}"
+          echo "Latest Nix version: ${latest_nix}"
+          echo "CURRENT_NIX=${current_nix}" >> $GITHUB_ENV
+          echo "LATEST_NIX=${latest_nix}" >> $GITHUB_ENV
           sed -i -E "s/nix_version=[0-9.]+/nix_version=${latest_nix}/" ./install-nix.sh
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v7
+        uses: peter-evans/create-pull-request@v8
         with:
-          title: Update nix versions
+          title: "nix: ${{ env.CURRENT_NIX }} -> ${{ env.LATEST_NIX }}"
+          commit-message: "nix: ${{ env.CURRENT_NIX }} -> ${{ env.LATEST_NIX }}"
+          body: |
+            This PR updates the Nix version from ${{ env.CURRENT_NIX }} to ${{ env.LATEST_NIX }}.
+
+            **To trigger the CI:**
+
+            1. Checkout the PR branch:
+               ```bash
+               gh pr checkout <pr-number>
+               ```
+
+            2. Amend and force push:
+               ```bash
+               git commit --amend --no-edit
+               git push --force-with-lease
+               ```
           labels: dependencies

README.md

@@ -1,24 +1,19 @@
 # install-nix-action
 
-![GitHub Actions badge](https://github.com/cachix/install-nix-action/workflows/install-nix-action%20test/badge.svg)
+[![Tests](https://github.com/cachix/install-nix-action/actions/workflows/test.yml/badge.svg)](https://github.com/cachix/install-nix-action/actions/workflows/test.yml)
 
-Installs [Nix](https://nixos.org/nix/) on GitHub Actions for the supported platforms: Linux and macOS.
-
-By default it has no nixpkgs configured, you have to set `nix_path`
-by [picking a channel](https://status.nixos.org/)
-or [pin nixpkgs yourself](https://nix.dev/reference/pinning-nixpkgs)
-(see also [pinning tutorial](https://nix.dev/tutorials/towards-reproducibility-pinning-nixpkgs)).
+Installs [Nix](https://nixos.org/nix/) on GitHub Actions runners for Linux and macOS.
 
 # Features
 
-- Quick installation (~4s on Linux, ~20s on macOS)
-- Multi-User installation (with sandboxing enabled only on Linux)
-- [Self-hosted GitHub runner](https://docs.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners) support
+- Quick installation (~4s on Linux / ~20s on macOS)
+- Multi-user installation with sandboxing enabled by default on Linux
+- Support for [self-hosted GitHub runners](https://docs.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners)
 - Allows specifying Nix installation URL via `install_url` (the oldest supported Nix version is 2.3.5)
 - Allows specifying extra Nix configuration options via `extra_nix_config`
 - Allows specifying `$NIX_PATH` and channels via `nix_path`
-- Share `/nix/store` between builds using [cachix-action](https://github.com/cachix/cachix-action) for simple binary cache setup to speed up your builds and share binaries with your team
 - Enables KVM on supported machines: run VMs and NixOS tests with full hardware-acceleration
+- Pair with a binary cache from [cachix-action](https://github.com/cachix/cachix-action) to speed up re-builds and share binaries across your team
 
 ## Usage
 
@@ -33,7 +28,7 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: cachix/install-nix-action@v31
       with:
         nix_path: nixpkgs=channel:nixos-unstable
@@ -51,7 +46,7 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: cachix/install-nix-action@v31
       with:
         github_access_token: ${{ secrets.GITHUB_TOKEN }}
@@ -59,24 +54,17 @@ jobs:
     - run: nix flake check
 ```
 
-To install Nix from any commit, go to [the corresponding installer_test action](https://github.com/NixOS/nix/runs/2219534360) and click on "Run cachix/install-nix-action@XX" step and expand the first line.
-
-## Inputs (specify using `with:`)
-
-- `extra_nix_config`: append to `/etc/nix/nix.conf`
-
-- `github_access_token`: configure Nix to pull from GitHub using the given GitHub token. This helps work around rate limit issues. Has no effect when `access-tokens` is also specified in `extra_nix_config`.
-
-- `install_url`: specify URL to install Nix from (useful for testing non-stable releases or pinning Nix, for example https://releases.nixos.org/nix/nix-2.3.7/install)
-
-- `install_options`: additional installer flags passed to the installer script.
-
-- `nix_path`: set `NIX_PATH` environment variable, for example `nixpkgs=channel:nixos-unstable`
-
-- `enable_kvm`: whether to enable KVM for hardware-accelerated virtualization on Linux. Enabled by default if available.
-
-- `set_as_trusted_user`: whether to add the current user to `trusted-users`. Enabled by default.
+## Inputs
 
+| Name | Description | Default |
+|------|-------------|---------|
+| `install_url` | URL to install Nix from. Useful for testing non-stable releases or pinning a specific Nix version (e.g., <https://releases.nixos.org/nix/nix-2.3.7/install>) | `""` |
+| `install_options` | Additional flags to pass to the Nix installer script | `""` |
+| `extra_nix_config` | Additional configuration to append to `/etc/nix/nix.conf` | `""` |
+| `nix_path` | Value to set for the `NIX_PATH` environment variable (e.g., `nixpkgs=channel:nixos-unstable`) | `""` |
+| `github_access_token` | GitHub token for Nix to use when pulling from GitHub repositories. Helps work around rate limit issues. Has no effect when `access-tokens` is specified in `extra_nix_config`. | `$GITHUB_TOKEN` if available |
+| `set_as_trusted_user` | Add the current user to the `trusted-users` list | `true` |
+| `enable_kvm` | Enable KVM for hardware-accelerated virtualization on Linux | `true` |
 
 ## Differences from the default Nix installer
 
@@ -106,19 +94,30 @@ Some settings have been optimised for use in CI environments:
 
 ## FAQ
 
-### How do I print nixpkgs version I have configured?
+### How do I print the nixpkgs version I've configured?
 
 ```yaml
 - name: Print nixpkgs version
   run: nix-instantiate --eval -E '(import <nixpkgs> {}).lib.version'
 ```
 
-### How do I run NixOS tests?
+### How do I add a nixpkgs channel?
 
-With the following inputs:
+This action doesn't set up any channels by default.
+Use `nix_path` to configure optional channels by [picking a channel](https://status.nixos.org/) or [pinning nixpkgs](https://nix.dev/reference/pinning-nixpkgs) to a specific commit.
 
 ```yaml
-- uses: cachix/install-nix-action@vXX
+- uses: cachix/install-nix-action@v31
+  with:
+    nix_path: nixpkgs=channel:nixos-unstable
+```
+
+See also the [tutorial on pinning on nix.dev](https://nix.dev/tutorials/towards-reproducibility-pinning-nixpkgs).
+
+### How do I run NixOS tests on Linux?
+
+```yaml
+- uses: cachix/install-nix-action@v31
   with:
     enable_kvm: true
     extra_nix_config: "system-features = nixos-test benchmark big-parallel kvm"
@@ -137,7 +136,7 @@ using [cachix-action](https://github.com/cachix/cachix-action), you
 should use their `extraPullNames` input like this:
 
 ```yaml
-- uses: cachix/cachix-action@vXX
+- uses: cachix/cachix-action@v31
    with:
      name: mycache
      authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
@@ -155,6 +154,22 @@ install-nix-action's own `extra_nix_config` input:
       substituters = https://hydra.iohk.io https://cache.nixos.org/
 ```
 
+### How do I configure steps to use my flake's development environment?
+
+You can configure [`jobs.<job_id>.steps[*].shell`](https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax#jobsjob_idstepsshell)
+to use `nix develop`.
+
+```yaml
+  # (optional) pre-build the shell separately to avoid skewing the run time of the next
+  #            step and have clear point of failure should the shell fail to build
+- name: Pre-build devShell
+  run: nix build --no-link .#devShells.$(nix eval --impure --raw --expr 'builtins.currentSystem').default
+
+- name: Run a command with nix develop
+  shell: 'nix develop -c bash -e {0}'
+  run: echo "hello, pure world!"
+```
+
 ### How do I pass environment variables to commands run with `nix develop` or `nix shell`?
 
 Nix runs commands in a restricted environment by default, called `pure mode`.
@@ -180,8 +195,9 @@ nix develop --impure
 In multi-user mode, Nix commands that operate on the Nix store are forwarded to a privileged daemon. This daemon runs in a separate context from your GitHub Actions workflow and cannot access the workflow's environment variables. Consequently, any secrets or credentials defined in your workflow environment will not be available to Nix operations that require store access.
 
 There are two ways to pass AWS credentials to the Nix daemon:
-  - Configure a default profile using the AWS CLI
-  - Install Nix in single-user mode
+
+- Configure a default profile using the AWS CLI
+- Install Nix in single-user mode
 
 #### Configure a default profile using the AWS CLI
 
@@ -198,10 +214,10 @@ job:
       id-token: write
       contents: read
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: cachix/install-nix-action@v31
       - name: Assume AWS Role
-        uses: aws-actions/configure-aws-credentials@v4.1.0
+        uses: aws-actions/configure-aws-credentials@v5.0.0
         with:
           aws-region: us-east-1
           role-to-assume: arn:aws-cn:iam::123456789100:role/my-github-actions-role

install-nix.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-if nix_path="$(type -p nix)" ; then
+if nix_path="$(type -p nix)"; then
   echo "Aborting: Nix is already installed at ${nix_path}"
   exit
 fi
@@ -26,11 +26,13 @@ trap 'rm -rf "$workdir"' EXIT
 
 # Configure Nix
 add_config() {
-  echo "$1" >> "$workdir/nix.conf"
+  echo "$1" >>"$workdir/nix.conf"
 }
 add_config "show-trace = true"
 # Set jobs to number of cores
 add_config "max-jobs = auto"
+# Configure the nix-daemon to use certificates.
+# In multi-user installs, NIX_SSL_CERT_FILE only works if set in the daemon's service file.
 if [[ $OSTYPE =~ darwin ]]; then
   add_config "ssl-cert-file = /etc/ssl/cert.pem"
 fi
@@ -70,8 +72,14 @@ installer_options=(
   --nix-extra-conf-file "$workdir/nix.conf"
 )
 
-# only use the nix-daemon settings if on darwin (which get ignored) or systemd is supported
+# Enable daemon on macOS and Linux systems with systemd, unless --no-daemon is specified
 if [[ (! $INPUT_INSTALL_OPTIONS =~ "--no-daemon") && ($OSTYPE =~ darwin || -e /run/systemd/system) ]]; then
+  use_daemon() { true; }
+else
+  use_daemon() { false; }
+fi
+
+if use_daemon; then
   installer_options+=(
     --daemon
     --daemon-user-count "$(python3 -c 'import multiprocessing as mp; print(mp.cpu_count() * 2)')"
@@ -86,7 +94,7 @@ else
 fi
 
 if [[ -n "${INPUT_INSTALL_OPTIONS:-}" ]]; then
-  IFS=' ' read -r -a extra_installer_options <<< "$INPUT_INSTALL_OPTIONS"
+  IFS=' ' read -r -a extra_installer_options <<<"$INPUT_INSTALL_OPTIONS"
   installer_options=("${extra_installer_options[@]}" "${installer_options[@]}")
 fi
 
@@ -94,9 +102,8 @@ echo "installer options: ${installer_options[*]}"
 
 # There is --retry-on-errors, but only newer curl versions support that
 curl_retries=5
-nix_version=2.29.0
-while ! curl -sS -o "$workdir/install" -v --fail -L "${INPUT_INSTALL_URL:-https://releases.nixos.org/nix/nix-${nix_version}/install}"
-do
+nix_version=2.33.0
+while ! curl -sS -o "$workdir/install" -v --fail -L "${INPUT_INSTALL_URL:-https://releases.nixos.org/nix/nix-${nix_version}/install}"; do
   sleep 1
   ((curl_retries--))
   if [[ $curl_retries -le 0 ]]; then
@@ -107,19 +114,72 @@ done
 
 sh "$workdir/install" "${installer_options[@]}"
 
-# Set paths
-echo "/nix/var/nix/profiles/default/bin" >> "$GITHUB_PATH"
-# new path for nix 2.14
-echo "$HOME/.nix-profile/bin" >> "$GITHUB_PATH"
+# Configure the environment
+#
+# Adapted from the single- and multi-user scripts:
+#   single-user: https://github.com/NixOS/nix/blob/master/scripts/nix-profile-daemon.sh.in
+#   multi-user: https://github.com/NixOS/nix/blob/master/scripts/nix-profile-daemon.sh.in
+#
+# These scripts would normally be evaluated as part of the user's shell profile.
+# GitHub doesn't evaluate profiles or rc scripts by default, so we set up the environment manually.
+echo "::debug::Nix installed, setting up environment"
 
+# Export the path to Nix
 if [[ -n "${INPUT_NIX_PATH:-}" ]]; then
-  echo "NIX_PATH=${INPUT_NIX_PATH}" >> "$GITHUB_ENV"
+  echo "NIX_PATH=${INPUT_NIX_PATH}" >>"$GITHUB_ENV"
 fi
 
-# Set temporary directory (if not already set) to fix https://github.com/cachix/install-nix-action/issues/197
+# Set temporary directory if not already set
+# Fixes https://github.com/cachix/install-nix-action/issues/197
 if [[ -z "${TMPDIR:-}" ]]; then
-  echo "TMPDIR=${RUNNER_TEMP}" >> "$GITHUB_ENV"
+  echo "TMPDIR=${RUNNER_TEMP}" >>"$GITHUB_ENV"
 fi
 
+# Determine the profile path.
+#
+# Different versions of Nix support (from newest to oldest):
+#   - NIX_STATE_HOME to fully control the location of home files
+#   - XDG_STATE_HOME, defaulting to .local/state/nix/profile
+#   - $HOME/.nix-profile
+#
+# These directories are created by calling `nix profile`, so they don't exist at this point.
+# Without parsing the Nix version, our best bet is the legacy-ish ~/.nix-profile.
+if [[ -n "${NIX_STATE_HOME:-}" ]]; then
+  NIX_LINK="$NIX_STATE_HOME/profile"
+else
+  NIX_LINK="$HOME/.nix-profile"
+fi
+
+# Set Nix profiles
+echo "NIX_PROFILES=/nix/var/nix/profiles/default $NIX_LINK" >>"$GITHUB_ENV"
+
+# Set NIX_SSL_CERT_FILE if not already configured
+if [[ -z "${NIX_SSL_CERT_FILE:-}" ]]; then
+  # Check common SSL certificate file locations
+  if [[ -e "/etc/ssl/certs/ca-certificates.crt" ]]; then # NixOS, Ubuntu, Debian, Gentoo, Arch
+    echo "NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt" >>"$GITHUB_ENV"
+  elif [[ $OSTYPE =~ darwin && -e "/etc/ssl/cert.pem" ]]; then # macOS
+    echo "NIX_SSL_CERT_FILE=/etc/ssl/cert.pem" >>"$GITHUB_ENV"
+  elif [[ -e "/etc/ssl/ca-bundle.pem" ]]; then # openSUSE Tumbleweed
+    echo "NIX_SSL_CERT_FILE=/etc/ssl/ca-bundle.pem" >>"$GITHUB_ENV"
+  elif [[ -e "/etc/ssl/certs/ca-bundle.crt" ]]; then # Old NixOS
+    echo "NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt" >>"$GITHUB_ENV"
+  elif [[ -e "/etc/pki/tls/certs/ca-bundle.crt" ]]; then # Fedora, CentOS
+    echo "NIX_SSL_CERT_FILE=/etc/pki/tls/certs/ca-bundle.crt" >>"$GITHUB_ENV"
+  elif [[ -e "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt" ]]; then # fall back to cacert in default Nix profile
+    echo "NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt" >>"$GITHUB_ENV"
+  elif [[ -e "$NIX_LINK/etc/ssl/certs/ca-bundle.crt" ]]; then # fall back to cacert in user Nix profile
+    echo "NIX_SSL_CERT_FILE=$NIX_LINK/etc/ssl/certs/ca-bundle.crt" >>"$GITHUB_ENV"
+  fi
+fi
+
+# Set paths based on the installation type
+if use_daemon; then
+  # Multi-user daemon install - add both paths
+  echo "/nix/var/nix/profiles/default/bin" >>"$GITHUB_PATH"
+fi
+# Always add the user profile path
+echo "$NIX_LINK/bin" >>"$GITHUB_PATH"
+
 # Close the log message group which was opened above
 echo "::endgroup::"

tests/test-env.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+echo "=== Testing Nix Environment Variables ==="
+echo
+
+# Test NIX_PROFILES
+echo "NIX_PROFILES: ${NIX_PROFILES:-<not set>}"
+if [[ -n "${NIX_PROFILES:-}" ]]; then
+  echo "✓ NIX_PROFILES is set"
+else
+  echo "✗ NIX_PROFILES is not set"
+  exit 1
+fi
+
+# Test NIX_SSL_CERT_FILE
+echo "NIX_SSL_CERT_FILE: ${NIX_SSL_CERT_FILE:-<not set>}"
+if [[ -n "${NIX_SSL_CERT_FILE:-}" ]]; then
+  if [[ -f "$NIX_SSL_CERT_FILE" ]]; then
+    echo "✓ NIX_SSL_CERT_FILE is set and file exists"
+  else
+    echo "✗ NIX_SSL_CERT_FILE is set but file does not exist: $NIX_SSL_CERT_FILE"
+    exit 1
+  fi
+else
+  echo "✗ NIX_SSL_CERT_FILE is not set"
+  exit 1
+fi
+
+# Test PATH contains Nix paths
+echo "PATH: $PATH"
+if echo "$PATH" | grep -E -q "(\.nix-profile|nix/profile)"; then
+  echo "✓ PATH contains Nix paths"
+else
+  echo "✗ PATH does not contain Nix paths"
+  exit 1
+fi
+
+# Test NIX_PATH if set
+if [[ -n "${NIX_PATH:-}" ]]; then
+  echo "NIX_PATH: $NIX_PATH"
+  echo "✓ NIX_PATH is set"
+else
+  echo "NIX_PATH: <not set>"
+  exit 1
+fi
+
+# Test TMPDIR
+echo "TMPDIR: ${TMPDIR:-<not set>}"
+if [[ -n "${TMPDIR:-}" ]]; then
+  echo "✓ TMPDIR is set"
+else
+  echo "⚠ TMPDIR is not set"
+  exit 1
+fi
+
+echo
+echo "=== Testing Nix Command ==="
+if command -v nix >/dev/null 2>&1; then
+  echo "✓ nix command is available"
+  echo "Nix version: $(nix --version)"
+else
+  echo "✗ nix command is not available"
+  exit 1
+fi
+
+echo
+echo "=== Environment Setup Test Complete ==="