[Fix #10833] Fix an incorrect autocorrect for Style/RedundantCondition

Fixes #10833.

This PR fixes an incorrect autocorrect for `Style/RedundantCondition`
when branches contains arithmetic operation.

changelog/fix_an_incorrect_autocorrect_for_style_redundant_condition.md

@@ -0,0 +1 @@
+* [#10833](https://github.com/rubocop/rubocop/issues/10833): Fix an incorrect autocorrect for `Style/RedundantCondition` when branches contains arithmetic operation. ([@koic][])

lib/rubocop/cop/style/redundant_condition.rb

@@ -154,16 +154,22 @@ def same_method?(if_branch, else_branch)
           if_branch.method?(else_branch.method_name) && if_branch.receiver == else_branch.receiver
         end
 
-        def if_source(if_branch)
+        def if_source(if_branch, arithmetic_operation)
           if branches_have_method?(if_branch.parent) && if_branch.parenthesized?
             if_branch.source.delete_suffix(')')
+          elsif arithmetic_operation
+            argument_source = if_branch.first_argument.source
+
+            "#{if_branch.receiver.source} #{if_branch.method_name} (#{argument_source}"
           else
             if_branch.source
           end
         end
 
-        def else_source(else_branch)
-          if branches_have_method?(else_branch.parent)
+        def else_source(else_branch, arithmetic_operation) # rubocop:disable Metrics/AbcSize
+          if arithmetic_operation
+            "#{else_branch.first_argument.source})"
+          elsif branches_have_method?(else_branch.parent)
             else_source_if_has_method(else_branch)
           elsif require_parentheses?(else_branch)
             "(#{else_branch.source})"
@@ -198,7 +204,12 @@ def else_source_if_has_assignment(else_branch)
 
         def make_ternary_form(node)
           _condition, if_branch, else_branch = *node
-          ternary_form = [if_source(if_branch), else_source(else_branch)].join(' || ')
+          arithmetic_operation = use_arithmetic_operation?(if_branch)
+
+          ternary_form = [
+            if_source(if_branch, arithmetic_operation),
+            else_source(else_branch, arithmetic_operation)
+          ].join(' || ')
           ternary_form += ')' if branches_have_method?(node) && if_branch.parenthesized?
 
           if node.parent&.send_type?
@@ -227,6 +238,10 @@ def require_braces?(node)
           node.hash_type? && !node.braces?
         end
 
+        def use_arithmetic_operation?(node)
+          node.respond_to?(:arithmetic_operation?) && node.arithmetic_operation?
+        end
+
         def without_argument_parentheses_method?(node)
           node.send_type? && !node.arguments.empty? &&
             !node.parenthesized? && !node.operator_method? && !node.assignment_method?

spec/rubocop/cop/style/redundant_condition_spec.rb

@@ -277,6 +277,21 @@ def test
         RUBY
       end
 
+      it 'registers an offense and corrects when the branches contains arithmetic operation' do
+        expect_offense(<<~RUBY)
+          if foo
+          ^^^^^^ Use double pipes `||` instead.
+            @value - foo
+          else
+            @value - 'bar'
+          end
+        RUBY
+
+        expect_correction(<<~RUBY)
+          @value - (foo || 'bar')
+        RUBY
+      end
+
       it 'registers an offense and corrects when the branches contains method call' do
         expect_offense(<<~RUBY)
           if foo