diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 2c379d0ae..008bb94d7 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1446,7 +1446,6 @@ Style/VariableInterpolation:
 Style/WhileUntilModifier:
   Exclude:
     - 'app/models/attachment.rb'
-    - 'lib/redmine/unified_diff.rb'
     - 'lib/redmine/utils.rb'
 
 # Cop supports --auto-correct.
diff --git a/lib/redmine/unified_diff.rb b/lib/redmine/unified_diff.rb
index 5660fa91d..64e3f13e8 100644
--- a/lib/redmine/unified_diff.rb
+++ b/lib/redmine/unified_diff.rb
@@ -203,11 +203,13 @@ module Redmine
       if line_left.present? && line_right.present? && line_left != line_right
         max = [line_left.size, line_right.size].min
         starting = 0
-        while starting < max && line_left[starting] == line_right[starting]
+        while starting < max &&
+                line_left[starting] == line_right[starting]
           starting += 1
         end
         ending = -1
-        while ending >= -(max - starting) && (line_left[ending] == line_right[ending])
+        while ending >= -(max - starting) &&
+               (line_left[ending] == line_right[ending])
           ending -= 1
         end
         unless starting == 0 && ending == -1