Check blank percent literal by `Layout/SpaceInsidePercentLiteralDelim…

…iters`

changelog/change_check_blank_percent_literal.md

@@ -0,0 +1 @@
+* [#11130](https://github.com/rubocop/rubocop/pull/11130): Check blank percent literal by `Layout/SpaceInsidePercentLiteralDelimiters`. ([@r7kamura][])

lib/rubocop/cop/layout/space_inside_array_percent_literal.rb

@@ -6,6 +6,9 @@ module Layout
       # Checks for unnecessary additional spaces inside array percent literals
       # (i.e. %i/%w).
       #
+      # Note that blank percent literals (e.g. `%i( )`) are checked by
+      # `Layout/SpaceInsidePercentLiteralDelimiters`.
+      #
       # @example
       #
       #   # bad

lib/rubocop/cop/layout/space_inside_percent_literal_delimiters.rb

@@ -8,14 +8,31 @@ module Layout
       #
       # @example
       #
+      #   # bad
+      #   %i( foo bar baz )
+      #
       #   # good
       #   %i(foo bar baz)
       #
       #   # bad
       #   %w( foo bar baz )
       #
+      #   # good
+      #   %w(foo bar baz)
+      #
       #   # bad
       #   %x(  ls -l )
+      #
+      #   # good
+      #   %x(ls -l)
+      #
+      #   # bad
+      #   %w( )
+      #   %w(
+      #   )
+      #
+      #   # good
+      #   %w()
       class SpaceInsidePercentLiteralDelimiters < Base
         include MatchRange
         include PercentLiteral
@@ -34,11 +51,21 @@ def on_xstr(node)
         end
 
         def on_percent_literal(node)
+          add_offenses_for_blank_spaces(node)
           add_offenses_for_unnecessary_spaces(node)
         end
 
         private
 
+        def add_offenses_for_blank_spaces(node)
+          range = body_range(node)
+          return if range.source.empty? || !range.source.strip.empty?
+
+          add_offense(range) do |corrector|
+            corrector.remove(range)
+          end
+        end
+
         def add_offenses_for_unnecessary_spaces(node)
           return unless node.single_line?
 
@@ -54,6 +81,13 @@ def regex_matches(node, &blk)
             each_match_range(contents_range(node), regex, &blk)
           end
         end
+
+        def body_range(node)
+          node.location.expression.with(
+            begin_pos: node.location.begin.end_pos,
+            end_pos: node.location.end.begin_pos
+          )
+        end
       end
     end
   end

spec/rubocop/cop/layout/space_inside_percent_literal_delimiters_spec.rb

@@ -86,6 +86,36 @@ def foo
         it 'accepts spaces between entries' do
           expect_no_offenses(code_example('a  b  c'))
         end
+
+        context 'with space in blank percent literals' do
+          it 'registers and corrects an offense' do
+            expect_offense(<<~RUBY)
+              #{code_example(' ')}
+                 ^ #{message}
+            RUBY
+
+            expect_correction("#{code_example('')}\n")
+          end
+        end
+
+        context 'with spaces in blank percent literals' do
+          it 'registers and corrects an offense' do
+            expect_offense(<<~RUBY)
+              #{code_example('  ')}
+                 ^^ #{message}
+            RUBY
+
+            expect_correction("#{code_example('')}\n")
+          end
+        end
+
+        context 'with newline in blank percent literals' do
+          it 'registers and corrects an offense' do
+            expect_offense(code_example("\n").lines.insert(1, "   ^{} #{message}\n").join)
+
+            expect_correction(code_example('').to_s)
+          end
+        end
       end
     end
   end