diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index c25f0ffce..c9b921590 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1144,7 +1144,6 @@ Style/ParallelAssignment:
 Style/ParenthesesAroundCondition:
   Exclude:
     - 'app/models/repository/subversion.rb'
-    - 'lib/diff.rb'
     - 'lib/redmine/helpers/gantt.rb'
     - 'lib/redmine/scm/adapters/cvs_adapter.rb'
     - 'lib/redmine/scm/adapters/git_adapter.rb'
diff --git a/lib/diff.rb b/lib/diff.rb
index 5c6eb4380..ca451ddf0 100644
--- a/lib/diff.rb
+++ b/lib/diff.rb
@@ -13,14 +13,14 @@ module RedmineDiff
       mvector = []
 
       # First we prune off any common elements at the beginning
-      while (astart <= afinish && bstart <= afinish && a[astart] == b[bstart])
+      while (astart <= afinish) && (bstart <= afinish) && (a[astart] == b[bstart])
         mvector[astart] = bstart
         astart += 1
         bstart += 1
       end
 
       # now the end
-      while (astart <= afinish && bstart <= bfinish && a[afinish] == b[bfinish])
+      while (astart <= afinish) && (bstart <= bfinish) && (a[afinish] == b[bfinish])
         mvector[afinish] = bfinish
         afinish -= 1
         bfinish -= 1