Add GitHub CI workflow for slim lint

.github/workflows/ci.yml

@@ -108,3 +108,33 @@ jobs:
           skip_install: true
           use_bundler: true
           fail_on_error: true
+
+  slim-lint:
+    permissions:
+      # Required: allow read access to the content for analysis.
+      contents: read
+      # Allow write access to checks to allow the action to annotate code in the PR.
+      checks: write
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.3
+          bundler-cache: true
+
+      - name: Run slim-lint
+        run: bundle exec slim-lint app/views --reporter checkstyle > checkstyle-result.xml
+
+      - name: Upload slim-lint results as GitHub annotations
+        uses: lcollins/checkstyle-github-action@v2.0.0
+        if: ${{ success() || failure() }}
+        with:
+          name: Slim-Lint Report
+          title: Analyze Slim templates for linting issues
+          path: checkstyle-result.xml

.slim-lint.yml

@@ -0,0 +1,32 @@
+linters:
+  # Disabled a few linters that are not relevant to our use case
+  EmptyLines:
+    enabled: false
+
+  ConsecutiveControlStatements:
+    enabled: false
+
+  LineLength:
+    enabled: false
+
+  # Enable additional linters
+  EmbeddedEngines:
+    enabled: true
+    forbidden_engines:
+      # JavaScript is not allowed due to our Content Security Policy (CSP)
+      - javascript
+
+  InstanceVariables:
+    enabled: false # TODO: Enable
+    include:
+      # Include only Rails partial templates by default
+      - app/views/**/_*.html.slim
+
+  StrictLocalsMissing:
+    enabled: false # TODO: Enable
+    include:
+      # Include only Rails partial templates by default
+      - app/views/**/_*.html.slim
+
+  Zwsp:
+    enabled: true

Gemfile

@@ -80,6 +80,7 @@ group :development, :staging do
   gem 'rubocop-performance'
   gem 'rubocop-rails', require: false
   gem 'rubocop-rspec'
+  gem 'slim_lint', require: false
 end
 
 group :test do

Gemfile.lock

@@ -499,6 +499,9 @@ GEM
       actionpack (>= 3.1)
       railties (>= 3.1)
       slim (>= 3.0, < 6.0, != 5.0.0)
+    slim_lint (0.27.0)
+      rubocop (>= 1.0, < 2.0)
+      slim (>= 3.0, < 6.0)
     snaky_hash (2.0.1)
       hashie
       version_gem (~> 1.1, >= 1.1.1)
@@ -641,6 +644,7 @@ DEPENDENCIES
   shoulda-matchers
   simplecov
   slim-rails
+  slim_lint
   sorcery
   sprockets-rails
   stackprof