From 66a6f2b15a8827f830db7bf8cf8c8ebba79fa237 Mon Sep 17 00:00:00 2001
From: Mike Dalessio <mike.dalessio@gmail.com>
Date: Tue, 30 Jan 2024 08:05:51 -0500
Subject: [PATCH] [rubygems/rubygems] feat: Gem::Requirement#initialize_copy
 deep-copies @requirements

to avoid accidentally mutating the original's state when doing:

```ruby
req2 = req.dup
req2.concat([">= 3.3.22"])
```

see https://github.com/rake-compiler/rake-compiler/pull/236 for a
real-world use case that would be made simpler with this behavior.

https://github.com/rubygems/rubygems/commit/8e0c03144e
---
 lib/rubygems/requirement.rb           | 5 +++++
 test/rubygems/test_gem_requirement.rb | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/lib/rubygems/requirement.rb b/lib/rubygems/requirement.rb
index 4ebafb065f..02543cb14a 100644
--- a/lib/rubygems/requirement.rb
+++ b/lib/rubygems/requirement.rb
@@ -284,6 +284,11 @@ class Gem::Requirement
   def _tilde_requirements
     @_tilde_requirements ||= _sorted_requirements.select {|r| r.first == "~>" }
   end
+
+  def initialize_copy(other) # :nodoc:
+    @requirements = other.requirements.dup
+    super
+  end
 end
 
 class Gem::Version
diff --git a/test/rubygems/test_gem_requirement.rb b/test/rubygems/test_gem_requirement.rb
index 57d143180f..de0d11ec00 100644
--- a/test/rubygems/test_gem_requirement.rb
+++ b/test/rubygems/test_gem_requirement.rb
@@ -12,6 +12,14 @@ class TestGemRequirement < Gem::TestCase
     assert_equal [[">=", v(1)], ["<", v(2)]], r.requirements
   end
 
+  def test_initialize_copy
+    r = req("= 1.2")
+    r2 = r.dup
+
+    assert_equal r.requirements, r2.requirements
+    refute_same r.requirements, r2.requirements
+  end
+
   def test_equals2
     r = req "= 1.2"
     assert_equal r, r.dup