chore: add GHA check

.github/workflows/composite/test-code/action.yml

@@ -11,6 +11,9 @@ runs:
       shell: bash
       run: mix compile --warnings-as-errors
 
+    - name: Run dialyzer
+      run: mix dialyzer --format github
+
     - name: Check formatting
       shell: bash
       run: mix format --check-formatted

.github/workflows/composite/test-setup/action.yml

@@ -5,6 +5,7 @@ runs:
   using: "composite"
   steps:
     - name: Set up Elixir
+      id: elixir-install
       uses: erlef/setup-beam@3ba5b86a2a6916f8cb0e64dcca30a56732a34bdf
       with:
         version-file: .tool-versions
@@ -20,3 +21,33 @@ runs:
     - name: Install dependencies
       shell: bash
       run: mix deps.get --check-locked
+
+    # Taken from dialyxir's documentation
+    # https://github.com/jeremyjh/dialyxir/blob/0091928de1ec01e30f82c50856f2dfe0a8f918ce/docs/github_actions.md
+    - name: Restore PLT cache
+      id: plt_cache
+      uses: actions/cache/restore@v3
+      with:
+        key: |
+          plt-${{ runner.os }}-${{ steps.elixir-install.outputs.otp-version }}-${{ steps.elixir-install.outputs.elixir-version }}-${{ hashFiles('**/mix.lock') }}
+        restore-keys: |
+          plt-${{ runner.os }}-${{ steps.elixir-install.outputs.otp-version }}-${{ steps.elixir-install.outputs.elixir-version }}-
+        path: |
+          priv/plts
+
+    # Create dialyzer's PLTs if no cache was found
+    - name: Create PLTs
+      if: steps.plt_cache.outputs.cache-hit != 'true'
+      run: mix dialyzer --plt
+
+    # By default, the GitHub Cache action will only save the cache if all steps in the job succeed,
+    # so we separate the cache restore and save steps in case running dialyzer fails.
+    - name: Save PLT cache
+      id: plt_cache_save
+      uses: actions/cache/save@v3
+      if: steps.plt_cache.outputs.cache-hit != 'true'
+      with:
+        key: |
+          plt-${{ runner.os }}-${{ steps.elixir-install.outputs.otp-version }}-${{ steps.elixir-install.outputs.elixir-version }}-${{ hashFiles('**/mix.lock') }}
+        path: |
+          priv/plts