From 3208ff2bf54f523da3b0fd849df3cf7e686771fa Mon Sep 17 00:00:00 2001
From: Christian Landsiedel <christian.landsiedel@microsoft.com>
Date: Thu, 22 Nov 2018 14:24:49 +0100
Subject: [PATCH 1/2] fix for creating new shadow class in python 3.6

---
 Lib/python/pyrun.swg | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/Lib/python/pyrun.swg b/Lib/python/pyrun.swg
index 7386ff7e2..650e30d3e 100644
--- a/Lib/python/pyrun.swg
+++ b/Lib/python/pyrun.swg
@@ -1205,12 +1205,16 @@ SWIG_Python_NewShadowInstance(SwigPyClientData *data, PyObject *swig_this)
 #if PY_VERSION_HEX >= 0x03000000
     PyObject *empty_args = PyTuple_New(0);
     if (empty_args) {
-      inst = ((PyTypeObject *)data->newargs)->tp_new((PyTypeObject *)data->newargs, empty_args, Py_None);
-      Py_DECREF(empty_args);
-      if (inst) {
-        PyObject_SetAttr(inst, SWIG_This(), swig_this);
-        Py_TYPE(inst)->tp_flags &= ~Py_TPFLAGS_VALID_VERSION_TAG;
+      PyObject *empty_kwargs = PyDict_New();
+      if (empty_kwargs) {
+        inst = ((PyTypeObject *)data->newargs)->tp_new((PyTypeObject *)data->newargs, empty_args, empty_kwargs);
+        Py_DECREF(empty_kwargs);
+        if (inst) {
+          PyObject_SetAttr(inst, SWIG_This(), swig_this);
+          Py_TYPE(inst)->tp_flags &= ~Py_TPFLAGS_VALID_VERSION_TAG;
+        }
       }
+      Py_DECREF(empty_args);
     }
 #else
     PyObject *dict = PyDict_New();

From 6e2b54be2f127ac03b5c23557bfd0037f362b46c Mon Sep 17 00:00:00 2001
From: William S Fulton <wsf@fultondesigns.co.uk>
Date: Thu, 20 Dec 2018 08:05:54 +0000
Subject: [PATCH 2/2] Testcase for testing __new__ override Python 3.6 fix

Issue #1357
---
 CHANGES.current                               |  5 ++++
 .../python/python_pythoncode_runme.py         |  4 +++
 Examples/test-suite/python_pythoncode.i       | 30 +++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/CHANGES.current b/CHANGES.current
index 6db8329c7..a231b03b3 100644
--- a/CHANGES.current
+++ b/CHANGES.current
@@ -7,6 +7,11 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.0.0 (in progress)
 ===========================
 
+2018-12-20: chlandsi
+            [Python] #1357. Fix overriding __new__ in Python 3.6.
+
+            Fixes SystemError: Objects/tupleobject.c:81: bad argument to internal function"
+
 2018-10-29: AlexanderGabriel
 	    [PHP] The following PHP7 reserved keywords are now only renamed by
 	    SWIG when used as function names in the API being wrapper:
diff --git a/Examples/test-suite/python/python_pythoncode_runme.py b/Examples/test-suite/python/python_pythoncode_runme.py
index da238780d..c27f4452d 100644
--- a/Examples/test-suite/python/python_pythoncode_runme.py
+++ b/Examples/test-suite/python/python_pythoncode_runme.py
@@ -3,3 +3,7 @@ import python_pythoncode
 # No need to actually do anything, this is a regression test for a bug which
 # caused an invalid python_pythoncode.py to be generated, so if we can import
 # it the bug is still fixed.
+
+# A later test enhancement checking __new__ requires some code...
+f = python_pythoncode.get_foo()
+f = python_pythoncode.Foo()
diff --git a/Examples/test-suite/python_pythoncode.i b/Examples/test-suite/python_pythoncode.i
index 70474d44c..8191aa121 100644
--- a/Examples/test-suite/python_pythoncode.i
+++ b/Examples/test-suite/python_pythoncode.i
@@ -29,3 +29,33 @@ struct TYPE2 {
 struct TYPE { };
 struct TYPE2 { };
 %}
+
+
+// Overriding __new__ test: https://github.com/swig/swig/pull/1357
+%inline %{
+class Foo {
+  public:
+    virtual ~Foo() {}
+    Foo() {}
+};
+
+Foo* get_foo() {return new Foo();}
+%}
+
+%pythoncode %{
+    print_debug = True
+%}
+
+%extend Foo {
+    // Note that %pythoncode is not available with -builtin
+    %pythoncode %{
+    def __new__(cls, *args, **kwargs):
+        if print_debug:
+            print('in Foo.__new__()')
+        return super(Foo, cls).__new__(cls)
+
+    def __init__(self):
+        if print_debug:
+            print('in Foo.__init__()')
+    %}
+};