Added clear cache methods to clear the internal type lookup cache for ref leak test runs.

Doc/c-api/type.rst

@@ -35,6 +35,13 @@ Type Objects
    .. versionadded:: 2.2
 
 
+.. cfunction:: unsigned int PyType_ClearCache(void)
+
+   Clears the internal lookup cache. Return the current version tag.
+
+   .. versionadded:: 2.6
+
+
 .. cfunction:: int PyType_HasFeature(PyObject *o, int feature)
 
    Return true if the type object *o* sets the feature *feature*.  Type features

Doc/library/sys.rst

@@ -58,6 +58,13 @@ always available.
    A string containing the copyright pertaining to the Python interpreter.
 
 
+.. function:: _cleartypecache()
+
+   Clear the internal type lookup cache.
+
+   .. versionadded:: 2.6
+
+
 .. function:: _current_frames()
 
    Return a dictionary mapping each thread's identifier to the topmost stack frame

Include/object.h

@@ -399,6 +399,7 @@ PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t);
 PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *,
 					       PyObject *, PyObject *);
 PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *);
+PyAPI_FUNC(unsigned int) PyType_ClearCache(void);
 
 /* Generic operations on objects */
 PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int);

Lib/test/regrtest.py

@@ -709,6 +709,9 @@ def dash_R_cleanup(fs, ps, pic, abcs):
     sys.path_importer_cache.clear()
     sys.path_importer_cache.update(pic)
 
+    # clear type cache
+    sys._cleartypecache()
+
     # Clear ABC registries, restoring previously saved ABC registries.
     for abc in [getattr(_abcoll, a) for a in _abcoll.__all__]:
         if not issubclass(abc, _Abstract):

Misc/NEWS

@@ -12,6 +12,9 @@ What's New in Python 2.6 alpha 1?
 Core and builtins
 -----------------
 
+- Added ``PyType_ClearCache()`` and ``sys._cleartypecache`` to clear the
+  internal lookup cache for ref leak tests.
+
 - Patch #1473257: generator objects gain a gi_code attribute. This is the
   same object as the func_code attribute of the function that produced the
   generator.

Objects/typeobject.c

@@ -32,6 +32,24 @@ struct method_cache_entry {
 
 static struct method_cache_entry method_cache[1 << MCACHE_SIZE_EXP];
 static unsigned int next_version_tag = 0;
+static void type_modified(PyTypeObject *);
+
+unsigned int
+PyType_ClearCache(void)
+{
+	Py_ssize_t i;
+	unsigned int cur_version_tag = next_version_tag - 1;
+	
+	for (i = 0; i < (1 << MCACHE_SIZE_EXP); i++) {
+		method_cache[i].version = 0;
+		Py_CLEAR(method_cache[i].name);
+		method_cache[i].value = NULL;
+	}
+	next_version_tag = 0;
+	/* mark all version tags as invalid */
+	type_modified(&PyBaseObject_Type);
+	return cur_version_tag;
+}
 
 static void
 type_modified(PyTypeObject *type)

Python/pythonrun.c

@@ -377,6 +377,9 @@ Py_Finalize(void)
 	Py_XDECREF(warnings_module);
 	warnings_module = NULL;
 
+	/* Clear type lookup cache */
+	PyType_ClearCache();
+
 	/* Collect garbage.  This may call finalizers; it's nice to call these
 	 * before all modules are destroyed.
 	 * XXX If a __del__ or weakref callback is triggered here, and tries to

Python/sysmodule.c

@@ -754,6 +754,17 @@ a 11-tuple where the entries in the tuple are counts of:\n\
 10. Number of stack pops performed by call_function()"
 );
 
+static PyObject *
+sys_cleartypecache(PyObject* self, PyObject* args)
+{
+	PyType_ClearCache();
+	Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(cleartypecache_doc,
+"_cleartypecache() -> None\n\
+Clear the internal type lookup cache.");
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -776,6 +787,8 @@ static PyMethodDef sys_methods[] = {
 	/* Might as well keep this in alphabetic order */
 	{"callstats", (PyCFunction)PyEval_GetCallStats, METH_NOARGS,
 	 callstats_doc},
+	{"_cleartypecache", sys_cleartypecache, METH_NOARGS,
+	 cleartypecache_doc},
 	{"_current_frames", sys_current_frames, METH_NOARGS,
 	 current_frames_doc},
 	{"displayhook",	sys_displayhook, METH_O, displayhook_doc},