[Fix rubocop#9608] Fix a false positive for `Layout/EmptyLineAfterGua…

…rdClause`

Fixes rubocop#9608.

This PR fixes a false positive for `Layout/EmptyLineAfterGuardClause`
when using guard clause is after `rubocop:enable` comment.

changelog/fix_false_positive_for_layout_empty_line_after_guard_clause.md

@@ -0,0 +1 @@
+* [#9608](https://github.com/rubocop/rubocop/issues/9608): Fix a false positive for `Layout/EmptyLineAfterGuardClause` when using guard clause is after `rubocop:enable` comment. ([@koic][])

lib/rubocop/cop/layout/empty_line_after_guard_clause.rb

@@ -47,14 +47,13 @@ def on_if(node)
 
           if node.modifier_form? && last_argument_is_heredoc?(node)
             heredoc_node = last_heredoc_argument(node)
-
-            return if next_line_empty?(heredoc_line(node, heredoc_node))
+            return if next_line_empty_or_enable_directive_comment?(heredoc_line(node, heredoc_node))
 
             add_offense(heredoc_node.loc.heredoc_end) do |corrector|
               autocorrect(corrector, heredoc_node)
             end
           else
-            return if next_line_empty?(node.last_line)
+            return if next_line_empty_or_enable_directive_comment?(node.last_line)
 
             add_offense(offense_location(node)) do |corrector|
               autocorrect(corrector, node)
@@ -71,6 +70,11 @@ def autocorrect(corrector, node)
                          range_by_whole_lines(node.source_range)
                        end
 
+          next_line = node_range.last_line + 1
+          if next_line_enable_directive_comment?(next_line)
+            node_range = processed_source.comment_at_line(next_line)
+          end
+
           corrector.insert_after(node_range, "\n")
         end
 
@@ -85,10 +89,23 @@ def contains_guard_clause?(node)
           node.if_branch&.guard_clause?
         end
 
+        def next_line_empty_or_enable_directive_comment?(line)
+          return true if next_line_empty?(line)
+
+          next_line = line + 1
+          next_line_enable_directive_comment?(next_line) && next_line_empty?(next_line)
+        end
+
         def next_line_empty?(line)
           processed_source[line].blank?
         end
 
+        def next_line_enable_directive_comment?(line)
+          return false unless (comment = processed_source.comment_at_line(line))
+
+          DirectiveComment.new(comment).enabled?
+        end
+
         def next_line_rescue_or_ensure?(node)
           parent = node.parent
           parent.nil? || parent.rescue_type? || parent.ensure_type?

lib/rubocop/directive_comment.rb

@@ -54,6 +54,11 @@ def disabled?
       %w[disable todo].include?(mode)
     end
 
+    # Checks if this directive enables cops
+    def enabled?
+      mode == 'enable'
+    end
+
     # Checks if this directive enables all cops
     def enabled_all?
       !disabled? && all_cops?

spec/rubocop/cop/layout/empty_line_after_guard_clause_spec.rb

@@ -199,6 +199,50 @@ def foo
     RUBY
   end
 
+  it 'registers and corrects when using guard clause is after `rubocop:disable` comment' do
+    expect_offense(<<~RUBY)
+      def foo
+        return if condition
+        ^^^^^^^^^^^^^^^^^^^ Add empty line after guard clause.
+        # rubocop:disable Department/Cop
+        bar
+        # rubocop:enable Department/Cop
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      def foo
+        return if condition
+
+        # rubocop:disable Department/Cop
+        bar
+        # rubocop:enable Department/Cop
+      end
+    RUBY
+  end
+
+  it 'registers and corrects when using guard clause is after `rubocop:enable` comment' do
+    expect_offense(<<~RUBY)
+      def foo
+        # rubocop:disable Department/Cop
+        return if condition
+        ^^^^^^^^^^^^^^^^^^^ Add empty line after guard clause.
+        # rubocop:enable Department/Cop
+        bar
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      def foo
+        # rubocop:disable Department/Cop
+        return if condition
+        # rubocop:enable Department/Cop
+
+        bar
+      end
+    RUBY
+  end
+
   it 'accepts modifier if' do
     expect_no_offenses(<<~RUBY)
       def foo
@@ -270,6 +314,18 @@ def foo
     RUBY
   end
 
+  it 'accepts using guard clause is after `rubocop:enable` comment' do
+    expect_no_offenses(<<~RUBY)
+      def foo
+        # rubocop:disable Department/Cop
+        return if condition
+        # rubocop:enable Department/Cop
+
+        bar
+      end
+    RUBY
+  end
+
   it 'accepts a guard clause inside oneliner block' do
     expect_no_offenses(<<~RUBY)
       def foo

spec/rubocop/directive_comment_spec.rb

@@ -133,6 +133,22 @@
     end
   end
 
+  describe '#enabled?' do
+    subject { directive_comment.enabled? }
+
+    [
+      ['when disable', '# rubocop:disable all', false],
+      ['when enable', '# rubocop:enable Foo/Bar', true],
+      ['when todo', '# rubocop:todo all', false]
+    ].each do |example|
+      context example[0] do
+        let(:text) { example[1] }
+
+        it { is_expected.to eq example[2] }
+      end
+    end
+  end
+
   describe '#all_cops?' do
     subject { directive_comment.all_cops? }