disable usage of _PyType_Lookup() in Py<=2.6/3.1

--HG--
extra : amend_source : c827dfd2e781c1a7e1b982601b6ee8e826d5b4ed

CHANGES.rst

@@ -11,6 +11,9 @@ Features added
 Bugs fixed
 ----------
 
+* Lookups of special methods (specifically for context managers) could fail
+  in Python <= 2.6/3.1.
+
 * Local variables were erroneously appended to the signature introspection
   of Cython implemented functions with keyword-only arguments under Python 3.
 

Cython/Utility/ObjectHandling.c

@@ -1029,7 +1029,8 @@ static CYTHON_INLINE PyObject *__Pyx_GetAttr(PyObject *o, PyObject *n) {
 /////////////// PyObjectLookupSpecial.proto ///////////////
 //@requires: PyObjectGetAttrStr
 
-#if CYTHON_COMPILING_IN_CPYTHON
+#if CYTHON_COMPILING_IN_CPYTHON && (PY_VERSION_HEX >= 0x03020000 || PY_MAJOR_VERSION < 3 && PY_VERSION_HEX >= 0x02070000)
+// looks like calling _PyType_Lookup() isn't safe in Py<=2.6/3.1
 static CYTHON_INLINE PyObject* __Pyx_PyObject_LookupSpecial(PyObject* obj, PyObject* attr_name) {
     PyObject *res;
     PyTypeObject *tp = Py_TYPE(obj);
@@ -1052,7 +1053,7 @@ static CYTHON_INLINE PyObject* __Pyx_PyObject_LookupSpecial(PyObject* obj, PyObj
     return res;
 }
 #else
-#define __Pyx_PyObject_LookupSpecial(o,n) PyObject_GetAttr(o,n)
+#define __Pyx_PyObject_LookupSpecial(o,n) __Pyx_PyObject_GetAttrStr(o,n)
 #endif
 
 /////////////// PyObjectGetAttrStr.proto ///////////////

runtests.py

@@ -207,6 +207,11 @@ EXT_EXTRAS = {
     'tag:trace':  update_linetrace_extension,
 }
 
+
+def _is_py3_before_32(excluded, version):
+    return version[0] >= 3 and version < (3,2)
+
+
 # TODO: use tags
 VER_DEP_MODULES = {
     # tests are excluded if 'CurrentPythonVersion OP VersionTuple', i.e.
@@ -252,6 +257,7 @@ VER_DEP_MODULES = {
     (2,7) : (operator.lt, lambda x: x in ['run.withstat_py', # multi context with statement
                                           'run.yield_inside_lambda',
                                           'run.test_dictviews',
+                                          'run.pyclass_special_methods',
                                           ]),
     # The next line should start (3,); but this is a dictionary, so
     # we can only have one (3,) key.  Since 2.7 is supposed to be the
@@ -263,7 +269,10 @@ VER_DEP_MODULES = {
     (3,): (operator.ge, lambda x: x in ['run.non_future_division',
                                         'compile.extsetslice',
                                         'compile.extdelslice',
-                                        'run.special_methods_T561_py2']),
+                                        'run.special_methods_T561_py2'
+                                        ]),
+    (3,1): (_is_py3_before_32, lambda x: x in ['run.pyclass_special_methods',
+                                               ]),
     (3,3) : (operator.lt, lambda x: x in ['build.package_compilation',
                                           ]),
     (3,4,0,'beta',3) : (operator.le, lambda x: x in ['run.py34_signature',