From d8cba5d16f1333fd625726fc72e66afbd45b8d00 Mon Sep 17 00:00:00 2001
From: Zackery Spytz <zspytz@gmail.com>
Date: Tue, 3 Jul 2018 13:47:22 -0600
Subject: [PATCH] bpo-24596: Decref module in PyRun_SimpleFileExFlags() on
 SystemExit (GH-7918)

PyErr_Print() will not return when the exception is a SystemExit, so
decref the __main__ module object in that case.
---
 Lib/test/test_gc.py                             | 17 ++++++++++++++++-
 .../2018-06-25-16-54-05.bpo-24596.Rkwova.rst    |  2 ++
 Python/pythonrun.c                              |  3 ++-
 3 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2018-06-25-16-54-05.bpo-24596.Rkwova.rst

diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
index 904fc7d88c0..8d806db3ba5 100644
--- a/Lib/test/test_gc.py
+++ b/Lib/test/test_gc.py
@@ -1,7 +1,7 @@
 import unittest
 from test.support import (verbose, refcount_test, run_unittest,
                           strip_python_stderr, cpython_only, start_threads,
-                          temp_dir, requires_type_collecting)
+                          temp_dir, requires_type_collecting, TESTFN, unlink)
 from test.support.script_helper import assert_python_ok, make_script
 
 import sys
@@ -708,6 +708,21 @@ class GCTests(unittest.TestCase):
             rc, out, err = assert_python_ok('-c', code)
             self.assertEqual(out.strip(), b'__del__ called')
 
+    @requires_type_collecting
+    def test_global_del_SystemExit(self):
+        code = """if 1:
+            class ClassWithDel:
+                def __del__(self):
+                    print('__del__ called')
+            a = ClassWithDel()
+            a.link = a
+            raise SystemExit(0)"""
+        self.addCleanup(unlink, TESTFN)
+        with open(TESTFN, 'w') as script:
+            script.write(code)
+        rc, out, err = assert_python_ok(TESTFN)
+        self.assertEqual(out.strip(), b'__del__ called')
+
     def test_get_stats(self):
         stats = gc.get_stats()
         self.assertEqual(len(stats), 3)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-06-25-16-54-05.bpo-24596.Rkwova.rst b/Misc/NEWS.d/next/Core and Builtins/2018-06-25-16-54-05.bpo-24596.Rkwova.rst
new file mode 100644
index 00000000000..1b33fd4a44d
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2018-06-25-16-54-05.bpo-24596.Rkwova.rst	
@@ -0,0 +1,2 @@
+Decref the module object in :c:func:`PyRun_SimpleFileExFlags` before calling
+:c:func:`PyErr_Print()`.  Patch by Zackery Spytz.
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 5cf7c33c93a..bcd1ca931d0 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -431,6 +431,7 @@ PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit,
     }
     flush_io();
     if (v == NULL) {
+        Py_CLEAR(m);
         PyErr_Print();
         goto done;
     }
@@ -439,7 +440,7 @@ PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit,
   done:
     if (set_file_name && PyDict_DelItemString(d, "__file__"))
         PyErr_Clear();
-    Py_DECREF(m);
+    Py_XDECREF(m);
     return ret;
 }