gh-117482: Simplify the Fix For Builtin Types Slot Wrappers (GH-122865)

In gh-121602, I applied a fix to a builtin types initialization bug.
That fix made sense in the context of some broader future changes,
but introduced a little bit of extra complexity. That fix has turned
out to be incomplete for some of the builtin types we haven't
been testing. I found that out while improving the tests.

A while back, @markshannon suggested a simpler fix that doesn't
have that problem, which I've already applied to 3.12 and 3.13.
I'm switching to that here. Given the potential long-term
benefits of the more complex (but still incomplete) approach,
I'll circle back to it in the future, particularly after I've improved
the tests so no corner cases slip through the cracks.

(This is effectively a "forward-port" of 716c677 from 3.13.)

Include/internal/pycore_typeobject.h

@@ -33,7 +33,6 @@ struct _types_runtime_state {
     struct {
         struct {
             PyTypeObject *type;
-            PyTypeObject def;
             int64_t interp_count;
         } types[_Py_MAX_MANAGED_STATIC_TYPES];
     } managed_static;

Lib/test/test_doctest/test_doctest.py

@@ -738,7 +738,7 @@ plain ol' Python and is guaranteed to be available.
 
     >>> import builtins
     >>> tests = doctest.DocTestFinder().find(builtins)
-    >>> 830 < len(tests) < 860 # approximate number of objects with docstrings
+    >>> 750 < len(tests) < 800 # approximate number of objects with docstrings
     True
     >>> real_tests = [t for t in tests if len(t.examples) > 0]
     >>> len(real_tests) # objects that actually have doctests

Lib/test/test_embed.py

@@ -416,7 +416,6 @@ class EmbeddingTests(EmbeddingTestsMixin, unittest.TestCase):
         out, err = self.run_embedded_interpreter("test_repeated_init_exec", code)
         self.assertEqual(out, '20000101\n' * INIT_LOOPS)
 
-    @unittest.skip('inheritance across re-init is currently broken; see gh-117482')
     def test_static_types_inherited_slots(self):
         script = textwrap.dedent("""
             import test.support

Lib/test/test_types.py

@@ -2410,9 +2410,6 @@ class SubinterpreterTests(unittest.TestCase):
         def collate_results(raw):
             results = {}
             for cls, attr, wrapper in raw:
-                # XXX This should not be necessary.
-                if cls == repr(bool) and attr in self.NUMERIC_METHODS:
-                    continue
                 key = cls, attr
                 assert key not in results, (results, key, wrapper)
                 results[key] = wrapper
@@ -2433,14 +2430,7 @@ class SubinterpreterTests(unittest.TestCase):
             cls, attr = key
             with self.subTest(cls=cls, slotattr=attr):
                 actual = interp_results.pop(key)
-                # XXX This should not be necessary.
-                if cls == "<class 'collections.OrderedDict'>" and attr == '__len__':
-                    continue
                 self.assertEqual(actual, expected)
-        # XXX This should not be necessary.
-        interp_results = {k: v for k, v in interp_results.items() if k[1] != '__hash__'}
-        # XXX This should not be necessary.
-        interp_results.pop(("<class 'collections.OrderedDict'>", '__getitem__'), None)
         self.maxDiff = None
         self.assertEqual(interp_results, {})
 

Objects/typeobject.c

@@ -314,15 +314,6 @@ managed_static_type_state_clear(PyInterpreterState *interp, PyTypeObject *self,
     }
 }
 
-static PyTypeObject *
-managed_static_type_get_def(PyTypeObject *self, int isbuiltin)
-{
-    size_t index = managed_static_type_index_get(self);
-    size_t full_index = isbuiltin
-        ? index
-        : index + _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES;
-    return &_PyRuntime.types.managed_static.types[full_index].def;
-}
 
 
 PyObject *
@@ -5927,6 +5918,7 @@ fini_static_type(PyInterpreterState *interp, PyTypeObject *type,
 
     _PyStaticType_ClearWeakRefs(interp, type);
     managed_static_type_state_clear(interp, type, isbuiltin, final);
+    /* We leave _Py_TPFLAGS_STATIC_BUILTIN set on tp_flags. */
 }
 
 void
@@ -7939,7 +7931,7 @@ inherit_slots(PyTypeObject *type, PyTypeObject *base)
     return 0;
 }
 
-static int add_operators(PyTypeObject *, PyTypeObject *);
+static int add_operators(PyTypeObject *type);
 static int add_tp_new_wrapper(PyTypeObject *type);
 
 #define COLLECTION_FLAGS (Py_TPFLAGS_SEQUENCE | Py_TPFLAGS_MAPPING)
@@ -8104,10 +8096,10 @@ type_dict_set_doc(PyTypeObject *type)
 
 
 static int
-type_ready_fill_dict(PyTypeObject *type, PyTypeObject *def)
+type_ready_fill_dict(PyTypeObject *type)
 {
     /* Add type-specific descriptors to tp_dict */
-    if (add_operators(type, def) < 0) {
+    if (add_operators(type) < 0) {
         return -1;
     }
     if (type_add_methods(type) < 0) {
@@ -8426,7 +8418,7 @@ type_ready_post_checks(PyTypeObject *type)
 
 
 static int
-type_ready(PyTypeObject *type, PyTypeObject *def, int initial)
+type_ready(PyTypeObject *type, int initial)
 {
     ASSERT_TYPE_LOCK_HELD();
 
@@ -8465,7 +8457,7 @@ type_ready(PyTypeObject *type, PyTypeObject *def, int initial)
     if (type_ready_set_new(type, initial) < 0) {
         goto error;
     }
-    if (type_ready_fill_dict(type, def) < 0) {
+    if (type_ready_fill_dict(type) < 0) {
         goto error;
     }
     if (initial) {
@@ -8522,7 +8514,7 @@ PyType_Ready(PyTypeObject *type)
     int res;
     BEGIN_TYPE_LOCK();
     if (!(type->tp_flags & Py_TPFLAGS_READY)) {
-        res = type_ready(type, NULL, 1);
+        res = type_ready(type, 1);
     } else {
         res = 0;
         assert(_PyType_CheckConsistency(type));
@@ -8558,20 +8550,14 @@ init_static_type(PyInterpreterState *interp, PyTypeObject *self,
 
     managed_static_type_state_init(interp, self, isbuiltin, initial);
 
-    PyTypeObject *def = managed_static_type_get_def(self, isbuiltin);
-    if (initial) {
-        memcpy(def, self, sizeof(PyTypeObject));
-    }
-
     int res;
     BEGIN_TYPE_LOCK();
-    res = type_ready(self, def, initial);
+    res = type_ready(self, initial);
     END_TYPE_LOCK();
     if (res < 0) {
         _PyStaticType_ClearWeakRefs(interp, self);
         managed_static_type_state_clear(interp, self, isbuiltin, initial);
     }
-
     return res;
 }
 
@@ -11182,6 +11168,26 @@ recurse_down_subclasses(PyTypeObject *type, PyObject *attr_name,
     return 0;
 }
 
+static int
+slot_inherited(PyTypeObject *type, pytype_slotdef *slotdef, void **slot)
+{
+    void **slot_base = slotptr(type->tp_base, slotdef->offset);
+    if (slot_base == NULL || *slot != *slot_base) {
+        return 0;
+    }
+
+    /* Some slots are inherited in pairs. */
+    if (slot == (void *)&type->tp_hash) {
+        return (type->tp_richcompare == type->tp_base->tp_richcompare);
+    }
+    else if (slot == (void *)&type->tp_richcompare) {
+        return (type->tp_hash == type->tp_base->tp_hash);
+    }
+
+    /* It must be inherited (see type_ready_inherit()). */
+    return 1;
+}
+
 /* This function is called by PyType_Ready() to populate the type's
    dictionary with method descriptors for function slots.  For each
    function slot (like tp_repr) that's defined in the type, one or more
@@ -11213,24 +11219,26 @@ recurse_down_subclasses(PyTypeObject *type, PyObject *attr_name,
    infinite recursion here.) */
 
 static int
-add_operators(PyTypeObject *type, PyTypeObject *def)
+add_operators(PyTypeObject *type)
 {
     PyObject *dict = lookup_tp_dict(type);
     pytype_slotdef *p;
     PyObject *descr;
     void **ptr;
 
-    assert(def == NULL || (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN));
-    if (def == NULL) {
-        def = type;
-    }
-
     for (p = slotdefs; p->name; p++) {
         if (p->wrapper == NULL)
             continue;
-        ptr = slotptr(def, p->offset);
+        ptr = slotptr(type, p->offset);
         if (!ptr || !*ptr)
             continue;
+        /* Also ignore when the type slot has been inherited. */
+        if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN
+            && type->tp_base != NULL
+            && slot_inherited(type, p, ptr))
+        {
+            continue;
+        }
         int r = PyDict_Contains(dict, p->name_strobj);
         if (r > 0)
             continue;