Fix Layout/LineLength reported length when ignoring directive comme…

…nts.

If `IgnoreCopDirectives` is enabled, the directive comment is not included in the calculation, but it is included in the count that is shown in the offense. This change make it not be included there either.

changelog/fix_fix_layoutlinelength_reported_length.md

@@ -0,0 +1 @@
+* [#10078](https://github.com/rubocop/rubocop/pull/10078): Fix `Layout/LineLength` reported length when ignoring directive comments. ([@dvandersluis][])

lib/rubocop/cop/layout/line_length.rb

@@ -183,8 +183,8 @@ def shebang?(line, line_index)
           line_index.zero? && line.start_with?('#!')
         end
 
-        def register_offense(loc, line, line_index)
-          message = format(MSG, length: line_length(line), max: max)
+        def register_offense(loc, line, line_index, length: line_length(line))
+          message = format(MSG, length: length, max: max)
 
           self.breakable_range = breakable_range_by_line_index[line_index]
 
@@ -241,17 +241,19 @@ def line_in_heredoc?(line_number)
         end
 
         def check_directive_line(line, line_index)
-          return if line_length_without_directive(line) <= max
+          length_without_directive = line_length_without_directive(line)
+          return if length_without_directive <= max
 
-          range = max..(line_length_without_directive(line) - 1)
+          range = max..(length_without_directive - 1)
           register_offense(
             source_range(
               processed_source.buffer,
               line_index + 1,
               range
             ),
             line,
-            line_index
+            line_index,
+            length: length_without_directive
           )
         end
 

spec/rubocop/cop/layout/line_length_spec.rb

@@ -345,15 +345,15 @@ def method_definition_that_is_just_under_the_line_length_limit(foo) # rubocop:di
       it 'highlights only the non-directive part' do
         expect_offense(<<~RUBY)
           #{'a' * 80}bcd # rubocop:enable Style/ClassVars
-          #{' ' * 80}^^^ Line is too long. [116/80]
+          #{' ' * 80}^^^ Line is too long. [83/80]
         RUBY
       end
 
       context 'and the source contains non-directive # as comment' do
         it 'highlights only the non-directive part' do
           expect_offense(<<~RUBY)
             #{'a' * 70} # bbbbbbbbbbbbbb # rubocop:enable Style/ClassVars'
-            #{' ' * 70}          ^^^^^^^ Line is too long. [121/80]
+            #{' ' * 70}          ^^^^^^^ Line is too long. [87/80]
           RUBY
         end
       end
@@ -362,7 +362,7 @@ def method_definition_that_is_just_under_the_line_length_limit(foo) # rubocop:di
         it 'registers an offense for the line' do
           expect_offense(<<-RUBY)
             LARGE_DATA_STRING_PATTERN = %r{\A([A-Za-z0-9\+\/#]*\={0,2})#([A-Za-z0-9\+\/#]*\={0,2})#([A-Za-z0-9\+\/#]*\={0,2})\z} # rubocop:disable Layout/LineLength
-            #{' ' * 68}^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Line is too long. [153/80]
+            #{' ' * 68}^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Line is too long. [117/80]
           RUBY
         end
       end