Close #12085: Fix an attribute error in subprocess.Popen destructor if the
constructor has failed, e.g. because of an undeclared keyword argument. Patch
written by Oleg Oshmyan.
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index b635ef3..73c1b5c 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -113,6 +113,16 @@
                              env=newenv)
         self.assertEqual(rc, 1)
 
+    def test_invalid_args(self):
+        # Popen() called with invalid arguments should raise TypeError
+        # but Popen.__del__ should not complain (issue #12085)
+        with support.captured_stderr() as s:
+            self.assertRaises(TypeError, subprocess.Popen, invalid_arg_name=1)
+            argcount = subprocess.Popen.__init__.__code__.co_argcount
+            too_many_args = [0] * (argcount + 1)
+            self.assertRaises(TypeError, subprocess.Popen, *too_many_args)
+        self.assertEqual(s.getvalue(), '')
+
     def test_stdin_none(self):
         # .stdin is None when not redirected
         p = subprocess.Popen([sys.executable, "-c", 'print "banana"'],