[pull] main from python:main

Doc/library/stdtypes.rst

@@ -5590,8 +5590,8 @@ can be used interchangeably to index the same dictionary entry.
 
 
    .. seealso::
-      :class:`types.MappingProxyType` can be used to create a read-only view
-      of a :class:`dict`.
+      :class:`frozendict` and :class:`types.MappingProxyType` can be used to
+      create a read-only view of a :class:`dict`.
 
 .. _thread-safety-dict:
 

Lib/test/pickletester.py

@@ -3167,6 +3167,7 @@ def test_builtin_types(self):
             'bytes': (3, 0),
             'BuiltinImporter': (3, 3),
             'str': (3, 4),  # not interoperable with Python < 3.4
+            'frozendict': (3, 15),
         }
         for t in builtins.__dict__.values():
             if isinstance(t, type) and not issubclass(t, BaseException):

Lib/test/test_dict.py

@@ -1767,6 +1767,9 @@ def test_update(self):
         self.assertEqual(copy, frozendict({'x': 1}))
 
     def test_repr(self):
+        d = frozendict()
+        self.assertEqual(repr(d), "frozendict()")
+
         d = frozendict(x=1, y=2)
         self.assertEqual(repr(d), "frozendict({'x': 1, 'y': 2})")
 
@@ -1775,6 +1778,15 @@ class MyFrozenDict(frozendict):
         d = MyFrozenDict(x=1, y=2)
         self.assertEqual(repr(d), "MyFrozenDict({'x': 1, 'y': 2})")
 
+    def test_hash(self):
+        # hash() doesn't rely on the items order
+        self.assertEqual(hash(frozendict(x=1, y=2)),
+                         hash(frozendict(y=2, x=1)))
+
+        fd = frozendict(x=[1], y=[2])
+        with self.assertRaisesRegex(TypeError, "unhashable type: 'list'"):
+            hash(fd)
+
 
 if __name__ == "__main__":
     unittest.main()

Lib/test/test_genericalias.py

@@ -101,7 +101,8 @@
 
 class BaseTest(unittest.TestCase):
     """Test basics."""
-    generic_types = [type, tuple, list, dict, set, frozenset, enumerate, memoryview,
+    generic_types = [type, tuple, list, dict, frozendict,
+                     set, frozenset, enumerate, memoryview,
                      slice,
                      defaultdict, deque,
                      SequenceMatcher,

Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst

@@ -0,0 +1,2 @@
+Optimize :meth:`!frozendict.fromkeys` to avoid unnecessary thread-safety operations
+in frozendict cases. Patch by Donghee Na.

Objects/dictobject.c

@@ -2671,10 +2671,8 @@ _PyDict_LoadBuiltinsFromGlobals(PyObject *globals)
 
 /* Consumes references to key and value */
 static int
-setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
+anydict_setitem_take2(PyDictObject *mp, PyObject *key, PyObject *value)
 {
-    ASSERT_DICT_LOCKED(mp);
-
     assert(key);
     assert(value);
     assert(PyAnyDict_Check(mp));
@@ -2693,6 +2691,14 @@ setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
     return insertdict(mp, key, hash, value);
 }
 
+/* Consumes references to key and value */
+static int
+setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
+{
+    ASSERT_DICT_LOCKED(mp);
+    return anydict_setitem_take2(mp, key, value);
+}
+
 int
 _PyDict_SetItem_Take2(PyDictObject *mp, PyObject *key, PyObject *value)
 {
@@ -3284,15 +3290,23 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         return NULL;
 
 
-    if (PyAnyDict_CheckExact(d)) {
-        if (PyAnyDict_CheckExact(iterable)) {
+    if (PyDict_CheckExact(d)) {
+        if (PyDict_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
             Py_BEGIN_CRITICAL_SECTION2(d, iterable);
             d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
             Py_END_CRITICAL_SECTION2();
             return d;
         }
+        else if (PyFrozenDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION(d);
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION();
+            return d;
+        }
         else if (PyAnySet_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
@@ -3302,14 +3316,37 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
             return d;
         }
     }
+    else if (PyFrozenDict_CheckExact(d)) {
+        if (PyDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION(iterable);
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION();
+            return d;
+        }
+        else if (PyFrozenDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            return d;
+        }
+        else if (PyAnySet_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION(iterable);
+            d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION();
+            return d;
+        }
+    }
 
     it = PyObject_GetIter(iterable);
     if (it == NULL){
         Py_DECREF(d);
         return NULL;
     }
 
-    if (PyAnyDict_CheckExact(d)) {
+    if (PyDict_CheckExact(d)) {
         Py_BEGIN_CRITICAL_SECTION(d);
         while ((key = PyIter_Next(it)) != NULL) {
             status = setitem_lock_held((PyDictObject *)d, key, value);
@@ -3321,7 +3358,19 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         }
 dict_iter_exit:;
         Py_END_CRITICAL_SECTION();
-    } else {
+    }
+    else if (PyFrozenDict_CheckExact(d)) {
+        while ((key = PyIter_Next(it)) != NULL) {
+            // anydict_setitem_take2 consumes a reference to key
+            status = anydict_setitem_take2((PyDictObject *)d,
+                                           key, Py_NewRef(value));
+            if (status < 0) {
+                assert(PyErr_Occurred());
+                goto Fail;
+            }
+        }
+    }
+    else {
         while ((key = PyIter_Next(it)) != NULL) {
             status = PyObject_SetItem(d, key, value);
             Py_DECREF(key);
@@ -7868,6 +7917,11 @@ static PyMethodDef frozendict_methods[] = {
 static PyObject *
 frozendict_repr(PyObject *self)
 {
+    PyDictObject *mp = _PyAnyDict_CAST(self);
+    if (mp->ma_used == 0) {
+        return PyUnicode_FromFormat("%s()", Py_TYPE(self)->tp_name);
+    }
+
     PyObject *repr = anydict_repr_impl(self);
     if (repr == NULL) {
         return NULL;
@@ -7881,33 +7935,55 @@ frozendict_repr(PyObject *self)
     return res;
 }
 
+static Py_uhash_t
+_shuffle_bits(Py_uhash_t h)
+{
+    return ((h ^ 89869747UL) ^ (h << 16)) * 3644798167UL;
+}
+
+// Code copied from frozenset_hash()
 static Py_hash_t
 frozendict_hash(PyObject *op)
 {
     PyFrozenDictObject *self = _PyFrozenDictObject_CAST(op);
-    Py_hash_t hash = FT_ATOMIC_LOAD_SSIZE_RELAXED(self->ma_hash);
-    if (hash != -1) {
-        return hash;
+    Py_hash_t shash = FT_ATOMIC_LOAD_SSIZE_RELAXED(self->ma_hash);
+    if (shash != -1) {
+        return shash;
     }
 
-    PyObject *items = _PyDictView_New(op, &PyDictItems_Type);
-    if (items == NULL) {
-        return -1;
-    }
-    PyObject *frozenset = PyFrozenSet_New(items);
-    Py_DECREF(items);
-    if (frozenset == NULL) {
-        return -1;
+    PyDictObject *mp = _PyAnyDict_CAST(op);
+    Py_uhash_t hash = 0;
+
+    PyObject *key, *value;  // borrowed refs
+    Py_ssize_t pos = 0;
+    while (PyDict_Next(op, &pos, &key, &value)) {
+        Py_hash_t key_hash = PyObject_Hash(key);
+        if (key_hash == -1) {
+            return -1;
+        }
+        hash ^= _shuffle_bits(key_hash);
+
+        Py_hash_t value_hash = PyObject_Hash(value);
+        if (value_hash == -1) {
+            return -1;
+        }
+        hash ^= _shuffle_bits(value_hash);
     }
 
-    hash = PyObject_Hash(frozenset);
-    Py_DECREF(frozenset);
-    if (hash == -1) {
-        return -1;
+    /* Factor in the number of active entries */
+    hash ^= ((Py_uhash_t)mp->ma_used + 1) * 1927868237UL;
+
+    /* Disperse patterns arising in nested frozendicts */
+    hash ^= (hash >> 11) ^ (hash >> 25);
+    hash = hash * 69069U + 907133923UL;
+
+    /* -1 is reserved as an error code */
+    if (hash == (Py_uhash_t)-1) {
+        hash = 590923713UL;
     }
 
-    FT_ATOMIC_STORE_SSIZE_RELAXED(self->ma_hash, hash);
-    return hash;
+    FT_ATOMIC_STORE_SSIZE_RELAXED(self->ma_hash, (Py_hash_t)hash);
+    return (Py_hash_t)hash;
 }
 
 

Objects/setobject.c

@@ -964,7 +964,10 @@ _shuffle_bits(Py_uhash_t h)
 
    This hash algorithm can be used on either a frozenset or a set.
    When it is used on a set, it computes the hash value of the equivalent
-   frozenset without creating a new frozenset object. */
+   frozenset without creating a new frozenset object.
+
+   If you update this code, update also frozendict_hash() which copied this
+   code. */
 
 static Py_hash_t
 frozenset_hash_impl(PyObject *self)