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[3.13] gh-117482: Simplify the Fix For Builtin Types Slot Wrappers (g…
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…h-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.
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@ericsnowcurrently
ericsnowcurrently authored Jul 24, 2024
1 parent 0952ea9 commit 716c677
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Showing 2 changed files with 93 additions and 31 deletions.
1 change: 0 additions & 1 deletion Include/internal/pycore_typeobject.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
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123 changes: 93 additions & 30 deletions Objects/typeobject.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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();

Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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));
Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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;
Expand Down

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