Issue #15001: fix segfault on "del sys.module['__main__']"

hynek · hynek · commit 15c02e304852 · 2012-11-07T09:10:49.000+01:00
Patch by Victor Stinner.
diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
@@ -375,6 +375,18 @@ def test_hash_randomization(self):
         self.assertEqual(rc, 0)
         self.assertIn(b'random is 1', out)
 
+    def test_del___main__(self):
+        # Issue #15001: PyRun_SimpleFileExFlags() did crash because it kept a
+        # borrowed reference to the dict of __main__ module and later modify
+        # the dict whereas the module was destroyed
+        filename = test.support.TESTFN
+        self.addCleanup(test.support.unlink, filename)
+        with open(filename, "w") as script:
+            print("import sys", file=script)
+            print("del sys.modules['__main__']", file=script)
+        assert_python_ok(filename)
+
+
 def test_main():
     test.support.run_unittest(CmdLineTest)
     test.support.reap_children()
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -10,6 +10,9 @@ What's New in Python 3.4.0 Alpha 1?
 Core and Builtins
 -----------------
 
+- Issue #15001: fix segfault on "del sys.module['__main__']". Patch by Victor
+  Stinner.
+
 - Issue #8271: the utf-8 decoder now outputs the correct number of U+FFFD
   characters when used with the 'replace' error handler on invalid utf-8
   sequences.  Patch by Serhiy Storchaka, tests by Ezio Melotti.
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
@@ -1390,25 +1390,26 @@ PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit,
 {
     PyObject *m, *d, *v;
     const char *ext;
-    int set_file_name = 0, ret;
+    int set_file_name = 0, ret = -1;
     size_t len;
 
     m = PyImport_AddModule("__main__");
     if (m == NULL)
         return -1;
+    Py_INCREF(m);
     d = PyModule_GetDict(m);
     if (PyDict_GetItemString(d, "__file__") == NULL) {
         PyObject *f;
         f = PyUnicode_DecodeFSDefault(filename);
         if (f == NULL)
-            return -1;
+            goto done;
         if (PyDict_SetItemString(d, "__file__", f) < 0) {
             Py_DECREF(f);
-            return -1;
+            goto done;
         }
         if (PyDict_SetItemString(d, "__cached__", Py_None) < 0) {
             Py_DECREF(f);
-            return -1;
+            goto done;
         }
         set_file_name = 1;
         Py_DECREF(f);
@@ -1422,7 +1423,6 @@ PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit,
             fclose(fp);
         if ((pyc_fp = fopen(filename, "rb")) == NULL) {
             fprintf(stderr, "python: Can't reopen .pyc file\n");
-            ret = -1;
             goto done;
         }
         /* Turn on optimization if a .pyo file is given */
@@ -1451,14 +1451,14 @@ PyRun_SimpleFileExFlags(FILE *fp, const char *filename, int closeit,
     flush_io();
     if (v == NULL) {
         PyErr_Print();
-        ret = -1;
         goto done;
     }
     Py_DECREF(v);
     ret = 0;
   done:
     if (set_file_name && PyDict_DelItemString(d, "__file__"))
         PyErr_Clear();
+    Py_DECREF(m);
     return ret;
 }
 
