[3.13] gh-117482: Simplify the Fix For Builtin Types Slot Wrappers (gh-121932)

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.  For earlier versions
those future changes are not relevant; we can avoid the extra complexity.
Thus we can revert that earlier change and replace it with this one,
which is more focused and conceptually simpler.  This is essentially
the implementation of an idea that @markshannon pointed out to me.

Note that this change would be much smaller if we didn't have to deal
with repr compatibility for builtin types that explicitly inherit tp slots
(see expect_manually_inherited()).  The alternative is to stop
*explicitly* inheriting tp slots in static PyTypeObject values,
which is churn that we can do separately.

diff --git a/Include/internal/pycore_typeobject.h b/Include/internal/pycore_typeobject.h
index 124efccb48bebd2dd5c40726f923908a94e7751c..05f125f928ca680efc20b78d0158e943a755d29b 100644 (file)
--- a/Include/internal/pycore_typeobject.h
+++ b/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;

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 1227f524a587bb7145b56156ba93e1cfae9fce1d..ad74164564861a11f61d5cfed3b69e680bc308b3 100644 (file)
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -314,16 +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;
-}
-
 // Also see _PyStaticType_InitBuiltin() and _PyStaticType_FiniBuiltin().
 
 /* end static builtin helpers */
@@ -5678,6 +5668,7 @@ 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
@@ -7688,7 +7679,7 @@ inherit_slots(PyTypeObject *type, PyTypeObject *base)
     return 0;
 }
 
-static int add_operators(PyTypeObject *, PyTypeObject *);
+static int add_operators(PyTypeObject *);
 static int add_tp_new_wrapper(PyTypeObject *type);
 
 #define COLLECTION_FLAGS (Py_TPFLAGS_SEQUENCE | Py_TPFLAGS_MAPPING)
@@ -7853,10 +7844,10 @@ 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) {
@@ -8175,7 +8166,7 @@ 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();
 
@@ -8214,7 +8205,7 @@ 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) {
@@ -8271,7 +8262,7 @@ 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));
@@ -8307,20 +8298,14 @@ 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;
 }
 
@@ -10877,6 +10862,69 @@ recurse_down_subclasses(PyTypeObject *type, PyObject *attr_name,
     return 0;
 }
 
+static int
+expect_manually_inherited(PyTypeObject *type, void **slot)
+{
+    PyObject *typeobj = (PyObject *)type;
+    if (slot == (void *)&type->tp_init) {
+        /* This is a best-effort list of builtin exception types
+           that have their own tp_init function. */
+        if (typeobj != PyExc_BaseException
+            && typeobj != PyExc_BaseExceptionGroup
+            && typeobj != PyExc_ImportError
+            && typeobj != PyExc_NameError
+            && typeobj != PyExc_OSError
+            && typeobj != PyExc_StopIteration
+            && typeobj != PyExc_SyntaxError
+            && typeobj != PyExc_UnicodeDecodeError
+            && typeobj != PyExc_UnicodeEncodeError)
+        {
+            return 1;
+        }
+    }
+    else if (slot == (void *)&type->tp_str) {
+        /* This is a best-effort list of builtin exception types
+           that have their own tp_str function. */
+        if (typeobj == PyExc_AttributeError || typeobj == PyExc_NameError) {
+            return 1;
+        }
+    }
+    else if (slot == (void *)&type->tp_getattr
+             || slot == (void *)&type->tp_getattro)
+    {
+        /* This is a best-effort list of builtin types
+           that have their own tp_getattr function. */
+        if (typeobj == PyExc_BaseException
+            || type == &PyBool_Type
+            || type == &PyByteArray_Type
+            || type == &PyBytes_Type
+            || type == &PyClassMethod_Type
+            || type == &PyComplex_Type
+            || type == &PyDict_Type
+            || type == &PyEnum_Type
+            || type == &PyFilter_Type
+            || type == &PyLong_Type
+            || type == &PyList_Type
+            || type == &PyMap_Type
+            || type == &PyMemoryView_Type
+            || type == &PyProperty_Type
+            || type == &PyRange_Type
+            || type == &PyReversed_Type
+            || type == &PySet_Type
+            || type == &PySlice_Type
+            || type == &PyStaticMethod_Type
+            || type == &PySuper_Type
+            || type == &PyTuple_Type
+            || type == &PyZip_Type)
+        {
+            return 1;
+        }
+    }
+
+    /* It must be inherited (see type_ready_inherit()).. */
+    return 0;
+}
+
 /* 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
@@ -10908,24 +10956,39 @@ 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;
+        if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN
+            && type->tp_base != NULL)
+        {
+            /* Also ignore when the type slot has been inherited. */
+            void **ptr_base = slotptr(type->tp_base, p->offset);
+            if (ptr_base && *ptr == *ptr_base) {
+                /* Ideally we would always ignore any manually inherited
+                   slots, Which would mean inheriting the slot wrapper
+                   using normal attribute lookup rather than keeping
+                   a distinct copy.  However, that would introduce
+                   a slight change in behavior that could break
+                   existing code.
+
+                   In the meantime, look the other way when the definition
+                   explicitly inherits the slot. */
+                if (!expect_manually_inherited(type, ptr)) {
+                    continue;
+                }
+            }
+        }
         int r = PyDict_Contains(dict, p->name_strobj);
         if (r > 0)
             continue;