Remove SystemArgumentInsteadOfClass linter and fix bug with whitespace in rendered class

.changeset/wet-houses-own.md

@@ -0,0 +1,5 @@
+---
+"@primer/view-components": patch
+---
+
+Remove SystemArgumentInsteadOfClass linter and fix bug with whitespace in rendered class

.rubocop.yml

@@ -57,9 +57,6 @@ Primer/NoTagMemoize:
   Include:
     - "app/components/**/*"
 
-Primer/SystemArgumentInsteadOfClass:
-  Enabled: true
-
 Lint/MissingSuper:
   Enabled: false
 

docs/contributors/linting.md

@@ -18,7 +18,7 @@ inherit_gem:
 You can also modify that configuration enabling/disabling the cops you want:
 
 ```yml
-Primer/SystemArgumentInsteadOfClass:
+Primer/NoTagMemoize:
   Enabled: false
 ```
 

lib/primer/classify.rb

@@ -49,7 +49,7 @@ def call(args = {})
             case key
             when :classes
               # insert :classes first to avoid huge doc diffs
-              result.unshift(val)
+              result.unshift(val) unless val.blank?
               next
             when :style
               style = val

lib/rubocop/config/default.yml

@@ -1,9 +1,6 @@
 require:
   - rubocop/cop/primer
 
-Primer/SystemArgumentInsteadOfClass:
-  Enabled: true
-
 Primer/NoTagMemoize:
   Enabled: false
 

test/components/base_component_test.rb

@@ -73,6 +73,12 @@ def test_does_not_render_class_attribute_if_none_is_set
     refute_selector("div[class='']")
   end
 
+  def test_renders_system_argument_class_with_no_whitespace
+    render_inline(Primer::BaseComponent.new(tag: :div, ml: 3))
+
+    assert_selector("div[class='ml-3']")
+  end
+
   def test_does_not_render_primer_layout_classes_as_attributes
     render_inline(Primer::BaseComponent.new(tag: :div, my: 4))