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GH-137759:Limit _PyObject_HashFast to dicts keys, rename it, and mark it as Py_ALWAYS_INLINE #137828

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GH-137759:Limit _PyObject_HashFast to dicts keys, rename it, and mark it as Py_ALWAYS_INLINE #137828

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GH-137759:Limit _PyObject_HashFast to dicts keys, rename it, and mark…
JasonMendoza2008 Aug 15, 2025
5fe204c
Merge branch 'main' into fix-issue-137759
JasonMendoza2008 Aug 15, 2025
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8 changes: 5 additions & 3 deletions Include/internal/pycore_object.h
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Original file line number Diff line number Diff line change
Expand Up @@ -858,9 +858,11 @@ _PyObject_IS_GC(PyObject *obj)
&& (type->tp_is_gc == NULL || type->tp_is_gc(obj)));
}

// Fast inlined version of PyObject_Hash()
static inline Py_hash_t
_PyObject_HashFast(PyObject *op)
// Fast inlined version of PyObject_Hash(). Dictionaries are very
// likely to include string keys (class and instance attributes,
// json, ...) so we include a fast path for strings.
static inline Py_ALWAYS_INLINE Py_hash_t
_PyObject_HashDictKey(PyObject *op)
{
if (PyUnicode_CheckExact(op)) {
Py_hash_t hash = FT_ATOMIC_LOAD_SSIZE_RELAXED(
Expand Down
2 changes: 1 addition & 1 deletion Modules/_collectionsmodule.c
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Expand Up @@ -2565,7 +2565,7 @@ _collections__count_elements_impl(PyObject *module, PyObject *mapping,
if (key == NULL)
break;

hash = _PyObject_HashFast(key);
hash = _PyObject_HashDictKey(key);
if (hash == -1) {
goto done;
}
Expand Down
30 changes: 15 additions & 15 deletions Objects/dictobject.c
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Expand Up @@ -2281,7 +2281,7 @@ dict_getitem(PyObject *op, PyObject *key, const char *warnmsg)
}
PyDictObject *mp = (PyDictObject *)op;

Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
PyErr_FormatUnraisable(warnmsg);
return NULL;
Expand Down Expand Up @@ -2349,7 +2349,7 @@ _PyDict_LookupIndex(PyDictObject *mp, PyObject *key)
assert(PyDict_CheckExact((PyObject*)mp));
assert(PyUnicode_CheckExact(key));

Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
return -1;
Expand Down Expand Up @@ -2446,7 +2446,7 @@ PyDict_GetItemRef(PyObject *op, PyObject *key, PyObject **result)
return -1;
}

Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
*result = NULL;
Expand All @@ -2462,7 +2462,7 @@ _PyDict_GetItemRef_Unicode_LockHeld(PyDictObject *op, PyObject *key, PyObject **
ASSERT_DICT_LOCKED(op);
assert(PyUnicode_CheckExact(key));

Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
*result = NULL;
Expand Down Expand Up @@ -2500,7 +2500,7 @@ PyDict_GetItemWithError(PyObject *op, PyObject *key)
PyErr_BadInternalCall();
return NULL;
}
hash = _PyObject_HashFast(key);
hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
return NULL;
Expand Down Expand Up @@ -2571,7 +2571,7 @@ _PyDict_LoadGlobal(PyDictObject *globals, PyDictObject *builtins, PyObject *key)
Py_hash_t hash;
PyObject *value;

hash = _PyObject_HashFast(key);
hash = _PyObject_HashDictKey(key);
if (hash == -1) {
return NULL;
}
Expand All @@ -2595,7 +2595,7 @@ _PyDict_LoadGlobalStackRef(PyDictObject *globals, PyDictObject *builtins, PyObje
Py_ssize_t ix;
Py_hash_t hash;

hash = _PyObject_HashFast(key);
hash = _PyObject_HashDictKey(key);
if (hash == -1) {
*res = PyStackRef_NULL;
return;
Expand Down Expand Up @@ -2658,7 +2658,7 @@ setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
assert(key);
assert(value);
assert(PyDict_Check(mp));
Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
Py_DECREF(key);
Expand Down Expand Up @@ -2810,7 +2810,7 @@ int
PyDict_DelItem(PyObject *op, PyObject *key)
{
assert(key);
Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
return -1;
Expand Down Expand Up @@ -3138,7 +3138,7 @@ pop_lock_held(PyObject *op, PyObject *key, PyObject **result)
return 0;
}

Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
if (result) {
Expand Down Expand Up @@ -3472,7 +3472,7 @@ dict_subscript(PyObject *self, PyObject *key)
Py_hash_t hash;
PyObject *value;

hash = _PyObject_HashFast(key);
hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
return NULL;
Expand Down Expand Up @@ -4353,7 +4353,7 @@ dict_get_impl(PyDictObject *self, PyObject *key, PyObject *default_value)
Py_hash_t hash;
Py_ssize_t ix;

hash = _PyObject_HashFast(key);
hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
return NULL;
Expand Down Expand Up @@ -4386,7 +4386,7 @@ dict_setdefault_ref_lock_held(PyObject *d, PyObject *key, PyObject *default_valu
return -1;
}

hash = _PyObject_HashFast(key);
hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
if (result) {
Expand Down Expand Up @@ -4816,7 +4816,7 @@ static PyMethodDef mapp_methods[] = {
int
PyDict_Contains(PyObject *op, PyObject *key)
{
Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = _PyObject_HashDictKey(key);
if (hash == -1) {
dict_unhashable_type(key);
return -1;
Expand Down Expand Up @@ -6903,7 +6903,7 @@ int
_PyDict_SetItem_LockHeld(PyDictObject *dict, PyObject *name, PyObject *value)
{
if (value == NULL) {
Py_hash_t hash = _PyObject_HashFast(name);
Py_hash_t hash = _PyObject_HashDictKey(name);
if (hash == -1) {
dict_unhashable_type(name);
return -1;
Expand Down
8 changes: 4 additions & 4 deletions Objects/setobject.c
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Expand Up @@ -231,7 +231,7 @@ set_unhashable_type(PyObject *key)
int
_PySet_AddTakeRef(PySetObject *so, PyObject *key)
{
Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = PyObject_Hash(key);
if (hash == -1) {
set_unhashable_type(key);
Py_DECREF(key);
Expand Down Expand Up @@ -400,7 +400,7 @@ set_discard_entry(PySetObject *so, PyObject *key, Py_hash_t hash)
static int
set_add_key(PySetObject *so, PyObject *key)
{
Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = PyObject_Hash(key);
if (hash == -1) {
set_unhashable_type(key);
return -1;
Expand All @@ -411,7 +411,7 @@ set_add_key(PySetObject *so, PyObject *key)
static int
set_contains_key(PySetObject *so, PyObject *key)
{
Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = PyObject_Hash(key);
if (hash == -1) {
set_unhashable_type(key);
return -1;
Expand All @@ -422,7 +422,7 @@ set_contains_key(PySetObject *so, PyObject *key)
static int
set_discard_key(PySetObject *so, PyObject *key)
{
Py_hash_t hash = _PyObject_HashFast(key);
Py_hash_t hash = PyObject_Hash(key);
if (hash == -1) {
set_unhashable_type(key);
return -1;
Expand Down
4 changes: 2 additions & 2 deletions Objects/typeobject.c
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Expand Up @@ -3749,7 +3749,7 @@ solid_base(PyTypeObject *type)
// or when __bases__ is re-assigned. Since the slots are read without atomic
// operations and without locking, we can only safely update them while the
// world is stopped. However, with the world stopped, we are very limited on
// which APIs can be safely used. For example, calling _PyObject_HashFast()
// which APIs can be safely used. For example, calling _PyObject_HashDictKey()
// or _PyDict_GetItemRef_KnownHash() are not safe and can potentially cause
// deadlocks. Hashing can be re-entrant and _PyDict_GetItemRef_KnownHash can
// acquire a lock if the dictionary is not owned by the current thread, to
Expand Down Expand Up @@ -5898,7 +5898,7 @@ PyObject_GetItemData(PyObject *obj)
static PyObject *
find_name_in_mro(PyTypeObject *type, PyObject *name, int *error)
{
Py_hash_t hash = _PyObject_HashFast(name);
Py_hash_t hash = _PyObject_HashDictKey(name);
if (hash == -1) {
*error = -1;
return NULL;
Expand Down
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