Fix bug in array pack with shared strings

If string literals are long and they become shared, we need to make them
independent before we can write to them. [Bug #19116]

1 files changed, 6 insertions, 0 deletions

diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 20e6ee7917..f58f8a2778 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -1294,6 +1294,12 @@ class TestArray < Test::Unit::TestCase
 =end
   end
 
+  def test_pack_with_buffer
+    n = [ 65, 66, 67 ]
+    str = "a" * 100
+    assert_equal("aaaABC", n.pack("@3ccc", buffer: str.dup), "[Bug #19116]")
+  end
+
   def test_pop
     a = @cls[ 'cat', 'dog' ]
     assert_equal('dog', a.pop)