Prevents bloat in themes by removing variable definitions that are no…

…t used

lib/theme_check/checks/unused_assign.rb

@@ -46,8 +46,9 @@ def on_end
       @templates.each_pair do |_, info|
         used = info.collect_used_assigns(@templates)
         info.assign_nodes.each_pair do |name, node|
-          unless used.include?(name)
-            add_offense("`#{name}` is never used", node: node)
+          next if used.include?(name)
+          add_offense("`#{name}` is never used", node: node) do |corrector|
+            corrector.remove(node)
           end
         end
       end

lib/theme_check/checks/unused_snippet.rb

@@ -25,7 +25,7 @@ def on_include(node)
     def on_end
       missing_snippets.each do |theme_file|
         add_offense("This snippet is not used", theme_file: theme_file) do |corrector|
-          corrector.remove(@theme, theme_file.relative_path.to_s)
+          corrector.remove_file(@theme, theme_file.relative_path.to_s)
         end
       end
     end

lib/theme_check/corrector.rb

@@ -14,6 +14,10 @@ def insert_before(node, content)
       @theme_file.rewriter.insert_before(node, content)
     end
 
+    def remove(node)
+      @theme_file.rewriter.remove(node)
+    end
+
     def replace(node, content)
       @theme_file.rewriter.replace(node, content)
       node.markup = content
@@ -32,7 +36,7 @@ def create_default_locale_json(theme)
       theme.default_locale_json.update_contents({})
     end
 
-    def remove(theme, relative_path)
+    def remove_file(theme, relative_path)
       theme.storage.remove(relative_path)
     end
 

lib/theme_check/liquid_node.rb

@@ -74,6 +74,16 @@ def end_index
       position.end_index
     end
 
+    def start_token_index
+      return position.start_index if inside_liquid_tag?
+      position.start_index - (start_token.length + 1)
+    end
+
+    def end_token_index
+      return position.end_index if inside_liquid_tag?
+      position.end_index + end_token.length
+    end
+
     # Literals are hard-coded values in the liquid file.
     def literal?
       @value.is_a?(String) || @value.is_a?(Integer)

lib/theme_check/theme_file_rewriter.rb

@@ -25,6 +25,12 @@ def insert_after(node, content)
       )
     end
 
+    def remove(node)
+      @rewriter.remove(
+        range(node.start_token_index, node.end_token_index)
+      )
+    end
+
     def replace(node, content)
       @rewriter.replace(
         range(node.start_index, node.end_index),

test/checks/unused_assign_test.rb

@@ -74,4 +74,36 @@ def test_recursion_in_includes
     )
     assert_offenses("", offenses)
   end
+
+  def test_removes_unused_assign
+    expected_sources = {
+      "templates/index.liquid" => "\n",
+    }
+    sources = fix_theme(
+      ThemeCheck::UnusedAssign.new,
+      "templates/index.liquid" => <<~END,
+        {% assign x = 1 %}
+      END
+    )
+    sources.each do |path, source|
+      assert_equal(expected_sources[path], source)
+    end
+  end
+
+  def test_removes_assign_leaves_html
+    expected_sources = {
+      "templates/index.liquid" => <<~END,
+        <p>test case</p>
+      END
+    }
+    sources = fix_theme(
+      ThemeCheck::UnusedAssign.new,
+      "templates/index.liquid" => <<~END,
+        <p>test case</p>{% assign x = 1 %}
+      END
+    )
+    sources.each do |path, source|
+      assert_equal(expected_sources[path], source)
+    end
+  end
 end