Fix when highlights contain multibyte characters

changelog/fix_when_highlights_contain_multibyte_characters.md

@@ -0,0 +1 @@
+* [#9649](https://github.com/rubocop/rubocop/pull/9649): Fix when highlights contain multibyte characters. ([@osyo-manga][])

lib/rubocop/formatter/clang_style_formatter.rb

@@ -49,8 +49,10 @@ def report_line(location)
       end
 
       def report_highlighted_area(highlighted_area)
-        output.puts("#{' ' * highlighted_area.begin_pos}" \
-                    "#{'^' * highlighted_area.size}")
+        space_area  = highlighted_area.source_buffer.slice(0...highlighted_area.begin_pos)
+        source_area = highlighted_area.source
+        output.puts("#{' ' * Unicode::DisplayWidth.of(space_area)}" \
+                    "#{'^' * Unicode::DisplayWidth.of(source_area)}")
       end
     end
   end

lib/rubocop/formatter/tap_formatter.rb

@@ -37,8 +37,10 @@ def report_line(location)
       end
 
       def report_highlighted_area(highlighted_area)
-        output.puts("# #{' ' * highlighted_area.begin_pos}" \
-                    "#{'^' * highlighted_area.size}")
+        space_area  = highlighted_area.source_buffer.slice(0...highlighted_area.begin_pos)
+        source_area = highlighted_area.source
+        output.puts("# #{' ' * Unicode::DisplayWidth.of(space_area)}" \
+                    "#{'^' * Unicode::DisplayWidth.of(source_area)}")
       end
 
       def report_offense(file, offense)

spec/rubocop/formatter/clang_style_formatter_spec.rb

@@ -123,5 +123,27 @@
           .to include(': [Corrected] This is a message.')
       end
     end
+
+    context 'when the source contains multibyte characters' do
+      let(:source) do
+        <<~RUBY
+          do_something("あああ", ["いいい"])
+        RUBY
+      end
+
+      it 'displays text containing the offending source line' do
+        location = source_range(source.index('[')..source.index(']'))
+
+        cop.add_offense(nil, location: location, message: 'message 1')
+        formatter.report_file('test', cop.offenses)
+
+        expect(output.string)
+          .to eq <<~OUTPUT
+            test:1:21: C: message 1
+            do_something("あああ", ["いいい"])
+                                   ^^^^^^^^^^
+        OUTPUT
+      end
+    end
   end
 end

spec/rubocop/formatter/tap_formatter_spec.rb

@@ -143,4 +143,33 @@
       end
     end
   end
+
+  describe '#report_file', :config do
+    let(:cop_class) { RuboCop::Cop::Cop }
+    let(:output) { StringIO.new }
+
+    before { cop.send(:begin_investigation, processed_source) }
+
+    context 'when the source contains multibyte characters' do
+      let(:source) do
+        <<~RUBY
+          do_something("あああ", ["いいい"])
+        RUBY
+      end
+
+      it 'displays text containing the offending source line' do
+        location = source_range(source.index('[')..source.index(']'))
+
+        cop.add_offense(nil, location: location, message: 'message 1')
+        formatter.report_file('test', cop.offenses)
+
+        expect(output.string)
+          .to eq <<~OUTPUT
+            # test:1:21: C: message 1
+            # do_something("あああ", ["いいい"])
+            #                        ^^^^^^^^^^
+        OUTPUT
+      end
+    end
+  end
 end