Add PyMethod_SetSelf to let extensions can set the im_self field in PyMethodObject

aq_log.txt

+..FF..................................E.F.F...
+======================================================================
+ERROR: test_w_unicode_attr_name (__main__.TestAcquire)
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "./lib/python2.7/site-packages/Acquisition-2.13.9-py2.7-linux-x86_64.egg/Acquisition/tests.py", line 2533, in test_w_unicode_attr_name
+    found = self.acquire(self.a.b.c, u'aq_parent')
+AttributeError: aq_parent
+
+======================================================================
+FAIL: test_Basic_gc (__main__)
+Doctest: __main__.test_Basic_gc
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "/srv/slapgrid/slappart13/pyston/build/Debug-gcc/lib/python2.7/doctest.py", line 2226, in runTest
+    raise self.failureException(self.format_failure(new.getvalue()))
+AssertionError: Failed doctest test for __main__.test_Basic_gc
+  File "./lib/python2.7/site-packages/Acquisition-2.13.9-py2.7-linux-x86_64.egg/Acquisition/tests.py", line 1738, in test_Basic_gc
+
+----------------------------------------------------------------------
+File "./lib/python2.7/site-packages/Acquisition-2.13.9-py2.7-linux-x86_64.egg/Acquisition/tests.py", line 1746, in __main__.test_Basic_gc
+Failed example:
+    for B in I, E:
+        class C1(B):
+            pass
+
+        class C2(Base):
+            def __del__(self):
+                print 'removed'
+
+        a=C1('a')
+        a.b = C1('a.b')
+        a.b.a = a
+        a.b.c = C2()
+        ignore = gc.collect()
+        del a
+        removed = gc.collect()
+        print removed > 0
+Expected:
+    removed
+    True
+    removed
+    True
+Got:
+    False
+    False
+
+
+======================================================================
+FAIL: test_Wrapper_gc (__main__)
+Doctest: __main__.test_Wrapper_gc
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "/srv/slapgrid/slappart13/pyston/build/Debug-gcc/lib/python2.7/doctest.py", line 2226, in runTest
+    raise self.failureException(self.format_failure(new.getvalue()))
+AssertionError: Failed doctest test for __main__.test_Wrapper_gc
+  File "./lib/python2.7/site-packages/Acquisition-2.13.9-py2.7-linux-x86_64.egg/Acquisition/tests.py", line 1771, in test_Wrapper_gc
+
+----------------------------------------------------------------------
+File "./lib/python2.7/site-packages/Acquisition-2.13.9-py2.7-linux-x86_64.egg/Acquisition/tests.py", line 1778, in __main__.test_Wrapper_gc
+Failed example:
+    for B in I, E:
+        class C:
+            def __del__(self):
+                print 'removed'
+
+        a=B('a')
+        a.b = B('b')
+        a.a_b = a.b # circ ref through wrapper
+        a.b.c = C()
+        ignored = gc.collect()
+        del a
+        removed = gc.collect()
+        removed > 0
+Expected:
+    removed
+    True
+    removed
+    True
+Got:
+    False
+    False
+
+
+======================================================================
+FAIL: test_explicit_aq_unicode_should_be_called (__main__.TestUnicode)
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "./lib/python2.7/site-packages/Acquisition-2.13.9-py2.7-linux-x86_64.egg/Acquisition/tests.py", line 2553, in test_explicit_aq_unicode_should_be_called
+    self.assertEqual(str(wrapped), repr(wrapped))
+AssertionError: '<__main__.A object at 0x7f50d5dd4d80>' != '<Acquisition.ExplicitAcquisitionWrapper object at 0x7f50d68c4ba0>'
+
+======================================================================
+FAIL: test_implicit_aq_unicode_should_be_called (__main__.TestUnicode)
+----------------------------------------------------------------------
+Traceback (most recent call last):
+  File "./lib/python2.7/site-packages/Acquisition-2.13.9-py2.7-linux-x86_64.egg/Acquisition/tests.py", line 2545, in test_implicit_aq_unicode_should_be_called
+    self.assertEqual(str(wrapped), repr(wrapped))
+AssertionError: '<__main__.A object at 0x7f50d5dd4330>' != '<Acquisition.ImplicitAcquisitionWrapper object at 0x7f50d68c4d50>'
+
+----------------------------------------------------------------------
+Ran 46 tests in 0.670s
+
+FAILED (failures=4, errors=1)

from_cpython/Include/classobject.h

@@ -75,6 +75,9 @@ PyAPI_FUNC(PyObject *) PyMethod_Function(PyObject *) PYSTON_NOEXCEPT;
 PyAPI_FUNC(PyObject *) PyMethod_Self(PyObject *) PYSTON_NOEXCEPT;
 PyAPI_FUNC(PyObject *) PyMethod_Class(PyObject *) PYSTON_NOEXCEPT;
 
+// Pyston change: add help API to allow extensions to set the fields of PyMethodObject
+
+PyAPI_FUNC(void) PyMethod_SetSelf(PyObject *, PyObject*) PYSTON_NOEXCEPT;
 /* Look up attribute with name (a string) on instance object pinst, using
  * only the instance and base class dicts.  If a descriptor is found in
  * a class dict, the descriptor is returned without calling it.

src/runtime/classobj.cpp

@@ -1927,6 +1927,18 @@ extern "C" PyObject* PyMethod_Self(PyObject* im) noexcept {
     return ((BoxedInstanceMethod*)im)->obj;
 }
 
+extern "C" void PyMethod_SetSelf(PyObject* im, PyObject* instance) noexcept {
+    if (!PyMethod_Check(im)) {
+        PyErr_BadInternalCall();
+    }
+
+    Box* self = ((BoxedInstanceMethod*)im)->obj;
+    Py_XDECREF(self);
+    Py_INCREF(instance);
+    ((BoxedInstanceMethod*)im)->obj = instance;
+    Py_INCREF(im);
+}
+
 extern "C" PyObject* PyMethod_Class(PyObject* im) noexcept {
     if (!PyMethod_Check(im)) {
         PyErr_BadInternalCall();