ci: Fix dialyzer cache

.github/workflows/test.yml

@@ -1,6 +1,13 @@
 name: Test
-on: push
-
+on:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+  push:
+    branches:
+      - main
 jobs:
   unit-test:
     runs-on: ubuntu-latest
@@ -38,6 +45,7 @@ jobs:
       - run: mix deps.get
       - run: mix credo
   dialyzer:
+    name: Run Dialyzer for type checking
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -47,15 +55,25 @@ jobs:
         with:
           path: deps
           key: ${{ runner.os }}-deps
-      - name: Cache PLT
-        id: cache-plt
-        uses: actions/cache@v2
-        with:
-          path: priv/plts
-          key: ${{ runner.os }}-plts
       - uses: erlef/setup-beam@v1
         with:
           otp-version: "22.2"
           elixir-version: "1.9.4"
-      - run: mix deps.get
-      - run: mix dialyzer
+      - name: Restore PLT cache
+        uses: actions/cache@v2
+        id: plt_cache
+        with:
+          key: |
+            ${{ runner.os }}-${{ steps.beam.outputs.elixir-version }}-${{ steps.beam.outputs.otp-version }}-plt
+          restore-keys: |
+            ${{ runner.os }}-${{ steps.beam.outputs.elixir-version }}-${{ steps.beam.outputs.otp-version }}-plt
+          path: |
+            priv/plts
+      # Create PLTs if no cache was found
+      - name: Create PLTs
+        if: steps.plt_cache.outputs.cache-hit != 'true'
+        run: mix dialyzer --plt
+      - name: Fetch dependencies
+        run: mix dialyzer
+      - name: Run dialyzer
+        run: mix dialyzer

mix.exs

@@ -36,7 +36,7 @@ defmodule Atomex.MixProject do
 
       # Dev
       {:credo, "~> 1.5", only: [:dev, :test], runtime: false},
-      {:dialyxir, "~> 1.0", only: :dev, runtime: false},
+      {:dialyxir, "~> 1.0", only: [:dev, :test], runtime: false},
       {:earmark, "~> 1.4", only: :dev, runtime: false},
       {:ex_doc, "~> 0.23", only: :dev, runtime: false},
       {:excoveralls, "~> 0.13", only: :test},