Cleans up CI and looser Elixir version requirement

Author: joladev

.github/workflows/ci.yml

@@ -4,41 +4,66 @@ on:
   push:
     branches: [main]
   pull_request:
+    branches: [main]
 
 jobs:
-  ci:
-    name: Elixir ${{ matrix.elixir }} / OTP ${{ matrix.otp }}
+  test:
+    name: Test (Elixir ${{ matrix.elixir }} / OTP ${{ matrix.otp }}${{ matrix.unlock && ' / unlock' || '' }})
     runs-on: ubuntu-latest
+
     strategy:
       fail-fast: false
       matrix:
         include:
-          # Latest, matches mise.toml.
+          - elixir: "1.15.0"
+            otp: "24.3"
+            unlock: false
+          - elixir: "1.19.5"
+            otp: "28.5"
+            unlock: false
           - elixir: "1.19.5"
             otp: "28.5"
-          # Floor of `elixir: "~> 1.18"`. Catches accidental use of features
-          # only present in newer Elixir/OTP releases.
-          - elixir: "1.18.0"
-            otp: "25.3"
+            unlock: true
+
+    env:
+      MIX_ENV: test
+
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: erlef/setup-beam@v1
         with:
-          otp-version: ${{ matrix.otp }}
           elixir-version: ${{ matrix.elixir }}
+          otp-version: ${{ matrix.otp }}
 
-      - name: Cache deps and build
-        uses: actions/cache@v4
+      - uses: actions/cache@v5
         with:
           path: |
             deps
             _build
-          key: ${{ runner.os }}-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-mix-${{ hashFiles('**/mix.lock') }}
-          restore-keys: ${{ runner.os }}-otp${{ matrix.otp }}-elixir${{ matrix.elixir }}-mix-
-
-      - run: mix deps.get
-      - run: mix format --check-formatted
-      - run: mix compile --warnings-as-errors
-      - run: mix test
-      - run: mix credo --strict
+          key: ${{ runner.os }}-mix-${{ matrix.elixir }}-${{ matrix.otp }}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-mix-${{ matrix.elixir }}-${{ matrix.otp }}-
+
+      - name: Check formatting
+        run: mix format --check-formatted
+
+      - name: Unlock deps
+        if: matrix.unlock
+        run: mix deps.unlock --all
+
+      - name: Check for unused deps in mix.lock
+        if: '!matrix.unlock'
+        run: mix deps.unlock --check-unused
+
+      - name: Install dependencies
+        run: mix deps.get
+
+      - name: Compile with warnings as errors
+        run: mix compile --warnings-as-errors
+
+      - name: Run Credo
+        run: mix credo --strict
+
+      - name: Run tests
+        run: mix test

mix.exs

@@ -5,7 +5,7 @@ defmodule HRW.MixProject do
     [
       app: :hrw,
       version: "0.2.0",
-      elixir: "~> 1.18",
+      elixir: "~> 1.15",
       start_permanent: Mix.env() == :prod,
       aliases: aliases(),
       deps: deps(),