chore: use nix for CI test

Author: lostbean

.github/workflows/ci.yml

@@ -1,87 +1,50 @@
 name: CI
 on:
   push:
-    branches: [main, master]
+    branches: [main]
   pull_request:
-    branches: [main, master]
-env:
-  MIX_ENV: test
-  ELIXIR_VERSION: '1.18'
-  OTP_VERSION: '27.2'
+    branches: [main]
+  workflow_dispatch:
 jobs:
   test:
-    name: Test (Elixir ${{ matrix.elixir }} / OTP ${{ matrix.otp }})
+    name: Test on Elixir (via Nix)
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        elixir: ['1.14', '1.15', '1.16', '1.17', '1.18']
-        otp: ['25.0', '26.0', '27.0']
-        exclude:
-          # OTP 25 is not compatible with Elixir 1.17+
-          - elixir: '1.17'
-            otp: '25.0'
-          - elixir: '1.18'
-            otp: '25.0'
-          # OTP 27 requires Elixir 1.17+
-          - elixir: '1.14'
-            otp: '27.0'
-          - elixir: '1.15'
-            otp: '27.0'
-          - elixir: '1.16'
-            otp: '27.0'
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
-      - name: Set up Elixir
-        uses: erlef/setup-beam@v1
+      - name: Install Nix
+        uses: cachix/install-nix-action@v27
         with:
-          elixir-version: ${{ matrix.elixir }}
-          otp-version: ${{ matrix.otp }}
-      - name: Restore dependencies cache
+          nix_path: nixpkgs=channel:nixos-unstable
+          extra_nix_config: |
+            experimental-features = nix-command flakes
+      - name: Cache Nix store
         uses: actions/cache@v4
         with:
           path: |
-            deps
-            _build
-          key: ${{ runner.os }}-mix-${{ matrix.otp }}-${{ matrix.elixir }}-${{ hashFiles('**/mix.lock') }}
+            ~/.cache/nix
+            /nix/store
+          key: ${{ runner.os }}-nix-${{ hashFiles('flake.nix', 'flake.lock') }}
           restore-keys: |
-            ${{ runner.os }}-mix-${{ matrix.otp }}-${{ matrix.elixir }}-
-      - name: Install dependencies
-        run: mix deps.get
-      - name: Run tests
-        run: mix test
-      - name: Run Credo
-        run: mix credo --strict
-  dialyzer:
-    name: Dialyzer
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-      - name: Set up Elixir
-        uses: erlef/setup-beam@v1
-        with:
-          elixir-version: ${{ env.ELIXIR_VERSION }}
-          otp-version: ${{ env.OTP_VERSION }}
-      - name: Restore dependencies cache
+            ${{ runner.os }}-nix-
+      - name: Cache Mix dependencies
         uses: actions/cache@v4
         with:
           path: |
             deps
             _build
-          key: ${{ runner.os }}-mix-${{ env.OTP_VERSION }}-${{ env.ELIXIR_VERSION }}-${{ hashFiles('**/mix.lock') }}
+          key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
           restore-keys: |
-            ${{ runner.os }}-mix-${{ env.OTP_VERSION }}-${{ env.ELIXIR_VERSION }}-
-      - name: Restore PLT cache
-        uses: actions/cache@v4
-        with:
-          path: priv/plts
-          key: ${{ runner.os }}-plt-${{ env.OTP_VERSION }}-${{ env.ELIXIR_VERSION }}-${{ hashFiles('**/mix.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-plt-${{ env.OTP_VERSION }}-${{ env.ELIXIR_VERSION }}-
-      - name: Install dependencies
-        run: mix deps.get
-      - name: Check formatting
-        run: mix format --check-formatted
+            ${{ runner.os }}-mix-
+      - name: Install Mix dependencies
+        run: nix develop -c mix deps.get
+      - name: Compile project
+        run: nix develop -c mix compile --warnings-as-errors
+      - name: Run tests
+        run: nix develop -c mix test
+      - name: Check code formatting
+        run: nix develop -c mix format --check-formatted
+      - name: Run Credo
+        run: nix develop -c mix credo
       - name: Run Dialyzer
-        run: mix dialyzer
+        run: nix develop -c mix dialyzer