From e6e20e3030863614ae8405fdd687dd33c5d0e5b2 Mon Sep 17 00:00:00 2001
From: Geremia Taglialatela <tagliala.dev@gmail.com>
Date: Sat, 16 Sep 2023 16:49:01 +0200
Subject: [PATCH] Set target version for `Performance/UnfreezeString`

As stated in the class documentation, unary plus operator is available
from Ruby 2.3.

This fix prevent RuboCop Performance to raise an offense when configured
to support Ruby 2.2
---
 changelog/fix_target_version_for_unfreeze_string_cop.md | 1 +
 lib/rubocop/cop/performance/unfreeze_string.rb          | 3 +++
 spec/rubocop/cop/performance/unfreeze_string_spec.rb    | 8 ++++++++
 3 files changed, 12 insertions(+)
 create mode 100644 changelog/fix_target_version_for_unfreeze_string_cop.md

diff --git a/changelog/fix_target_version_for_unfreeze_string_cop.md b/changelog/fix_target_version_for_unfreeze_string_cop.md
new file mode 100644
index 0000000000..c9573238d6
--- /dev/null
+++ b/changelog/fix_target_version_for_unfreeze_string_cop.md
@@ -0,0 +1 @@
+* [#373](https://github.com/rubocop/rubocop-performance/pull/373): Set target version for `Performance/UnfreezeString`. ([@tagliala][])
diff --git a/lib/rubocop/cop/performance/unfreeze_string.rb b/lib/rubocop/cop/performance/unfreeze_string.rb
index 7860c269c7..1b101dc8c8 100644
--- a/lib/rubocop/cop/performance/unfreeze_string.rb
+++ b/lib/rubocop/cop/performance/unfreeze_string.rb
@@ -26,6 +26,9 @@ module Performance
       #   +''
       class UnfreezeString < Base
         extend AutoCorrector
+        extend TargetRubyVersion
+
+        minimum_target_ruby_version 2.3
 
         MSG = 'Use unary plus to get an unfrozen string literal.'
         RESTRICT_ON_SEND = %i[dup new].freeze
diff --git a/spec/rubocop/cop/performance/unfreeze_string_spec.rb b/spec/rubocop/cop/performance/unfreeze_string_spec.rb
index 5db13a118d..d8e27b6151 100644
--- a/spec/rubocop/cop/performance/unfreeze_string_spec.rb
+++ b/spec/rubocop/cop/performance/unfreeze_string_spec.rb
@@ -112,4 +112,12 @@
       String.new(capacity: 100)
     RUBY
   end
+
+  context 'when Ruby <= 2.2', :ruby22 do
+    it 'does not register an offense for an empty string with `.dup`' do
+      expect_no_offenses(<<~RUBY)
+        "".dup
+      RUBY
+    end
+  end
 end