[ruby/tempfile] Fix Tempfile#{dup,clone}

Instead of storing the delegate in @tmpfile, use __getobj__, since
delegate library already handles dup/clone for that.  Copy the
unlinked, mode, and opts instance variables to the returned object
when using dup/clone.

Split the close/unlink finalizer into two finalizers. The close
finalizer always closes when any Tempfile instance is GCed, since
each Tempfile instance uses a separate file descriptor. The unlink
finalizer unlinks only when the original and all duped/cloned
Tempfiles are GCed, since all share the same path.

For Tempfile#open, undefine the close finalizer after closing the
current file, the redefine the close finalizer with the new file.

Fixes [Bug #19441]

https://github.com/ruby/tempfile/commit/dafabf9c7b

1 files changed, 16 insertions, 0 deletions

diff --git a/test/test_tempfile.rb b/test/test_tempfile.rb
index 87c1241df8..d5d684b016 100644
--- a/test/test_tempfile.rb
+++ b/test/test_tempfile.rb
@@ -63,6 +63,22 @@ class TestTempfile < Test::Unit::TestCase
     assert_match(/\.txt$/, File.basename(t.path))
   end
 
+  def test_dup
+    t = tempfile
+    t2 = t.dup
+    t2.close
+    assert_equal true, t2.closed?
+    assert_equal false, t.closed?
+  end
+
+  def test_clone
+    t = tempfile
+    t2 = t.clone
+    t2.close
+    assert_equal true, t2.closed?
+    assert_equal false, t.closed?
+  end
+
   def test_unlink
     t = tempfile("foo")
     path = t.path