https://github.com/python/cpython/commit/0a51113a4901502e1e14c892e4c31768a14faa60
commit: 0a51113a4901502e1e14c892e4c31768a14faa60
branch: main
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2026-03-04T20:49:20+01:00
summary:
gh-141510: Optimize PyDict_Copy() for frozendict (#145509)
Implement fast-path for frozendict in PyDict_Copy().
files:
M Objects/dictobject.c
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 0f123c3c2bb994..2552216152f98d 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -896,24 +896,20 @@ free_values(PyDictValues *values, bool use_qsbr)
PyMem_Free(values);
}
-/* Consumes a reference to the keys object */
-static PyObject *
-new_dict(PyDictKeysObject *keys, PyDictValues *values,
- Py_ssize_t used, int free_values_on_failure)
+static inline PyObject *
+new_dict_impl(PyDictObject *mp, PyDictKeysObject *keys,
+ PyDictValues *values, Py_ssize_t used,
+ int free_values_on_failure)
{
assert(keys != NULL);
- PyDictObject *mp = _Py_FREELIST_POP(PyDictObject, dicts);
if (mp == NULL) {
- mp = PyObject_GC_New(PyDictObject, &PyDict_Type);
- if (mp == NULL) {
- dictkeys_decref(keys, false);
- if (free_values_on_failure) {
- free_values(values, false);
- }
- return NULL;
+ dictkeys_decref(keys, false);
+ if (free_values_on_failure) {
+ free_values(values, false);
}
+ return NULL;
}
- assert(Py_IS_TYPE(mp, &PyDict_Type));
+
mp->ma_keys = keys;
mp->ma_values = values;
mp->ma_used = used;
@@ -923,6 +919,29 @@ new_dict(PyDictKeysObject *keys, PyDictValues *values,
return (PyObject *)mp;
}
+/* Consumes a reference to the keys object */
+static PyObject *
+new_dict(PyDictKeysObject *keys, PyDictValues *values,
+ Py_ssize_t used, int free_values_on_failure)
+{
+ PyDictObject *mp = _Py_FREELIST_POP(PyDictObject, dicts);
+ if (mp == NULL) {
+ mp = PyObject_GC_New(PyDictObject, &PyDict_Type);
+ }
+ assert(mp == NULL || Py_IS_TYPE(mp, &PyDict_Type));
+
+ return new_dict_impl(mp, keys, values, used, free_values_on_failure);
+}
+
+/* Consumes a reference to the keys object */
+static PyObject *
+new_frozendict(PyDictKeysObject *keys, PyDictValues *values,
+ Py_ssize_t used, int free_values_on_failure)
+{
+ PyDictObject *mp = PyObject_GC_New(PyDictObject, &PyFrozenDict_Type);
+ return new_dict_impl(mp, keys, values, used, free_values_on_failure);
+}
+
static PyObject *
new_dict_with_shared_keys(PyDictKeysObject *keys)
{
@@ -4313,8 +4332,7 @@ copy_lock_held(PyObject *o, int as_frozendict)
if (Py_TYPE(mp)->tp_iter == dict_iter &&
mp->ma_values == NULL &&
- (mp->ma_used >= (mp->ma_keys->dk_nentries * 2) / 3) &&
- !as_frozendict)
+ (mp->ma_used >= (mp->ma_keys->dk_nentries * 2) / 3))
{
/* Use fast-copy if:
@@ -4334,9 +4352,15 @@ copy_lock_held(PyObject *o, int as_frozendict)
if (keys == NULL) {
return NULL;
}
- PyDictObject *new = (PyDictObject *)new_dict(keys, NULL, 0, 0);
+ PyDictObject *new;
+ if (as_frozendict) {
+ new = (PyDictObject *)new_frozendict(keys, NULL, 0, 0);
+ }
+ else {
+ new = (PyDictObject *)new_dict(keys, NULL, 0, 0);
+ }
if (new == NULL) {
- /* In case of an error, `new_dict()` takes care of
+ /* In case of an error, new_dict()/new_frozendict() takes care of
cleaning up `keys`. */
return NULL;
}
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