Remove _PyModule_GetGCHooks; get the hooks directly via internal API

Author: encukou

Include/moduleobject.h

@@ -96,8 +96,6 @@ struct PyModuleDef_Slot {
 
 #ifndef Py_LIMITED_API
 #define _Py_mod_LAST_SLOT 13
-PyAPI_FUNC(int) _PyModule_GetGCHooks(
-    PyObject *, traverseproc*, inquiry*, freefunc*);  // For testing
 #endif
 
 #endif /* New in 3.5 */

Lib/test/test_capi/test_module.py

@@ -85,6 +85,15 @@ def test_gc(self):
         self.assertEqual(mod.__name__, 'testmod')
         self.assertEqual(mod.__doc__, None)
 
+        # Check that the requested hook functions (which module_from_slots_gc
+        # stores as attributes) match what's in the module (as retrieved by
+        # _testinternalcapi.module_get_gc_hooks)
+        _testinternalcapi = import_helper.import_module('_testinternalcapi')
+        traverse, clear, free = _testinternalcapi.module_get_gc_hooks(mod)
+        self.assertEqual(traverse, mod.traverse)
+        self.assertEqual(clear, mod.clear)
+        self.assertEqual(free, mod.free)
+
     def test_token(self):
         mod = _testcapi.module_from_slots_token(FakeSpec())
         self.assertIsInstance(mod, types.ModuleType)

Modules/_testcapi/module.c

@@ -99,13 +99,18 @@ module_from_slots_gc(PyObject *self, PyObject *spec)
     traverseproc traverse;
     inquiry clear;
     freefunc free;
-    if (_PyModule_GetGCHooks(mod, &traverse, &clear, &free) < 0) {
+    if (PyModule_Add(mod, "traverse", PyLong_FromVoidPtr(&noop_traverse)) < 0) {
+        Py_DECREF(mod);
+        return NULL;
+    }
+    if (PyModule_Add(mod, "clear", PyLong_FromVoidPtr(&noop_clear)) < 0) {
+        Py_DECREF(mod);
+        return NULL;
+    }
+    if (PyModule_Add(mod, "free", PyLong_FromVoidPtr(&noop_free)) < 0) {
         Py_DECREF(mod);
         return NULL;
     }
-    assert(traverse == &noop_traverse);
-    assert(clear == &noop_clear);
-    assert(free == &noop_free);
     return mod;
 }
 

Modules/_testinternalcapi.c

@@ -2418,6 +2418,34 @@ set_vectorcall_nop(PyObject *self, PyObject *func)
     Py_RETURN_NONE;
 }
 
+static PyObject *
+module_get_gc_hooks(PyObject *self, PyObject *arg)
+{
+    PyModuleObject *mod = (PyModuleObject *)arg;
+    PyObject *traverse = NULL;
+    PyObject *clear = NULL;
+    PyObject *free = NULL;
+    PyObject *result = NULL;
+    traverse = PyLong_FromVoidPtr(mod->md_state_traverse);
+    if (!traverse) {
+        goto finally;
+    }
+    clear = PyLong_FromVoidPtr(mod->md_state_clear);
+    if (!clear) {
+        goto finally;
+    }
+    free = PyLong_FromVoidPtr(mod->md_state_free);
+    if (!free) {
+        goto finally;
+    }
+    result = PyTuple_FromArray((PyObject*[]){ traverse, clear, free }, 3);
+finally:
+    Py_XDECREF(traverse);
+    Py_XDECREF(clear);
+    Py_XDECREF(free);
+    return result;
+}
+
 static PyMethodDef module_functions[] = {
     {"get_configs", get_configs, METH_NOARGS},
     {"get_recursion_depth", get_recursion_depth, METH_NOARGS},
@@ -2527,6 +2555,7 @@ static PyMethodDef module_functions[] = {
 #endif
     {"simple_pending_call", simple_pending_call, METH_O},
     {"set_vectorcall_nop", set_vectorcall_nop, METH_O},
+    {"module_get_gc_hooks", module_get_gc_hooks, METH_O},
     {NULL, NULL} /* sentinel */
 };
 

Objects/moduleobject.c

@@ -828,21 +828,6 @@ PyModule_GetToken(PyObject *m, void **token_p)
     return 0;
 }
 
-int
-_PyModule_GetGCHooks(PyObject *m, traverseproc *traverse,
-                     inquiry *clear, freefunc *free)
-{
-    if (!PyModule_Check(m)) {
-        PyErr_BadInternalCall();
-        return -1;
-    }
-    PyModuleObject *mod = (PyModuleObject *)m;
-    *traverse = mod->md_state_traverse;
-    *clear = mod->md_state_clear;
-    *free = mod->md_state_free;
-    return 0;
-}
-
 PyObject*
 PyModule_GetNameObject(PyObject *mod)
 {