[pull] main from python:main

Lib/multiprocessing/dummy/__init__.py

@@ -33,7 +33,7 @@
 
 class DummyProcess(threading.Thread):
 
-    def __init__(self, group=None, target=None, name=None, args=(), kwargs={}):
+    def __init__(self, group=None, target=None, name=None, args=(), kwargs=None):
         threading.Thread.__init__(self, group, target, name, args, kwargs)
         self._pid = None
         self._children = weakref.WeakKeyDictionary()

Lib/multiprocessing/process.py

@@ -77,7 +77,7 @@ class BaseProcess(object):
     def _Popen(self):
         raise NotImplementedError
 
-    def __init__(self, group=None, target=None, name=None, args=(), kwargs={},
+    def __init__(self, group=None, target=None, name=None, args=(), kwargs=None,
                  *, daemon=None):
         assert group is None, 'group argument must be None for now'
         count = next(_process_counter)
@@ -89,7 +89,7 @@ def __init__(self, group=None, target=None, name=None, args=(), kwargs={},
         self._closed = False
         self._target = target
         self._args = tuple(args)
-        self._kwargs = dict(kwargs)
+        self._kwargs = dict(kwargs) if kwargs else {}
         self._name = name or type(self).__name__ + '-' + \
                      ':'.join(str(i) for i in self._identity)
         if daemon is not None:

Lib/test/_test_multiprocessing.py

@@ -5278,6 +5278,23 @@ def test_invalid_handles(self):
                           multiprocessing.connection.Connection, -1)
 
 
+#
+# Regression tests for BaseProcess kwargs handling
+#
+
+class TestBaseProcessKwargs(unittest.TestCase):
+    def test_default_kwargs_not_shared_between_instances(self):
+        # Creating multiple Process instances without passing kwargs
+        # must create independent empty dicts (no shared state).
+        p1 = multiprocessing.Process(target=lambda: None)
+        p2 = multiprocessing.Process(target=lambda: None)
+        self.assertIsInstance(p1._kwargs, dict)
+        self.assertIsInstance(p2._kwargs, dict)
+        self.assertIsNot(p1._kwargs, p2._kwargs)
+        # Mutating one should not affect the other
+        p1._kwargs['x'] = 1
+        self.assertNotIn('x', p2._kwargs)
+
 
 @hashlib_helper.requires_hashdigest('sha256')
 class OtherTest(unittest.TestCase):

Lib/test/test_math.py

@@ -1485,7 +1485,9 @@ def __rmul__(self, other):
 
         # Error cases that arose during development
         args = ((-5, -5, 10), (1.5, 4611686018427387904, 2305843009213693952))
-        self.assertEqual(sumprod(*args), 0.0)
+        self.assertEqual(sumprod(*args), -7.5)
+        self.assertEqual(sumprod([-0.01, 1, -1, 0.01], [1, 1, 1, 1]), 0.0)
+        self.assertEqual(sumprod([1, 1, 1, 1], [-0.01, 1, -1, 0.01], ), 0.0)
 
     @requires_IEEE_754
     @unittest.skipIf(HAVE_DOUBLE_ROUNDING,

Lib/test/test_peg_generator/test_pegen.py

@@ -1106,3 +1106,49 @@ def test_deep_nested_rule(self) -> None:
         )
 
         self.assertEqual(output, expected_output)
+
+    def test_rule_flags(self) -> None:
+        """Test the new rule flags syntax that accepts arbitrary lists of flags."""
+        # Test grammar with various flag combinations
+        grammar_source = """
+        start: simple_rule
+
+        simple_rule (memo):
+            | "hello"
+
+        multi_flag_rule (memo, custom, test):
+            | "world"
+
+        single_custom_flag (custom):
+            | "test"
+
+        no_flags_rule:
+            | "plain"
+        """
+
+        grammar: Grammar = parse_string(grammar_source, GrammarParser)
+        rules = grammar.rules
+
+        # Test memo-only rule
+        simple_rule = rules['simple_rule']
+        self.assertTrue(simple_rule.memo, "simple_rule should have memo=True")
+        self.assertEqual(simple_rule.flags, frozenset(['memo']),
+                        f"simple_rule flags should be {'memo'}, got {simple_rule.flags}")
+
+        # Test multi-flag rule
+        multi_flag_rule = rules['multi_flag_rule']
+        self.assertTrue(multi_flag_rule.memo, "multi_flag_rule should have memo=True")
+        self.assertEqual(multi_flag_rule.flags, frozenset({'memo', 'custom', 'test'}),
+                        f"multi_flag_rule flags should contain memo, custom, test, got {multi_flag_rule.flags}")
+
+        # Test single custom flag rule
+        single_custom_rule = rules['single_custom_flag']
+        self.assertFalse(single_custom_rule.memo, "single_custom_flag should have memo=False")
+        self.assertEqual(single_custom_rule.flags, frozenset(['custom']),
+                        f"single_custom_flag flags should be {'custom'}, got {single_custom_rule.flags}")
+
+        # Test no flags rule
+        no_flags_rule = rules['no_flags_rule']
+        self.assertFalse(no_flags_rule.memo, "no_flags_rule should have memo=False")
+        self.assertEqual(no_flags_rule.flags, [],
+                        f"no_flags_rule flags should be the empty set, got {no_flags_rule.flags}")

Misc/NEWS.d/next/Core_and_Builtins/2025-09-17-13-21-26.gh-issue-139074.dVZO5F.rst

@@ -0,0 +1,2 @@
+Fixed a missing case in :func:`math.sumprod` where a low precision path was
+taken when an int/int input pair followed a float input.

Misc/NEWS.d/next/Library/2025-09-17-08-32-43.gh-issue-138813.LHkHjX.rst

@@ -0,0 +1 @@
+:class:`!multiprocessing.BaseProcess` defaults ``kwargs`` to ``None`` instead of a shared dictionary.

Modules/mathmodule.c

@@ -2937,32 +2937,31 @@ math_sumprod_impl(PyObject *module, PyObject *p, PyObject *q)
 
             if (!finished) {
                 double flt_p, flt_q;
-                bool p_type_float = PyFloat_CheckExact(p_i);
-                bool q_type_float = PyFloat_CheckExact(q_i);
-                if (p_type_float && q_type_float) {
-                    flt_p = PyFloat_AS_DOUBLE(p_i);
-                    flt_q = PyFloat_AS_DOUBLE(q_i);
-                } else if (p_type_float && (PyLong_CheckExact(q_i) || PyBool_Check(q_i))) {
-                    /* We care about float/int pairs and int/float pairs because
-                       they arise naturally in several use cases such as price
-                       times quantity, measurements with integer weights, or
-                       data selected by a vector of bools. */
+
+                if (PyFloat_CheckExact(p_i)) {
                     flt_p = PyFloat_AS_DOUBLE(p_i);
-                    flt_q = PyLong_AsDouble(q_i);
-                    if (flt_q == -1.0 && PyErr_Occurred()) {
+                } else if (PyLong_CheckExact(p_i) || PyBool_Check(p_i)) {
+                    flt_p = PyLong_AsDouble(p_i);
+                    if (flt_p == -1.0 && PyErr_Occurred()) {
                         PyErr_Clear();
                         goto finalize_flt_path;
                     }
-                } else if (q_type_float && (PyLong_CheckExact(p_i) || PyBool_Check(p_i))) {
+                } else {
+                    goto finalize_flt_path;
+                }
+
+                if (PyFloat_CheckExact(q_i)) {
                     flt_q = PyFloat_AS_DOUBLE(q_i);
-                    flt_p = PyLong_AsDouble(p_i);
-                    if (flt_p == -1.0 && PyErr_Occurred()) {
+                } else if (PyLong_CheckExact(q_i) || PyBool_Check(q_i)) {
+                    flt_q = PyLong_AsDouble(q_i);
+                    if (flt_q == -1.0 && PyErr_Occurred()) {
                         PyErr_Clear();
                         goto finalize_flt_path;
                     }
                 } else {
                     goto finalize_flt_path;
                 }
+
                 TripleLength new_flt_total = tl_fma(flt_p, flt_q, flt_total);
                 if (isfinite(new_flt_total.hi)) {
                     flt_total = new_flt_total;

Tools/peg_generator/pegen/c_generator.py

@@ -595,7 +595,7 @@ def _set_up_rule_memoization(self, node: Rule, result_type: str) -> None:
         self.print(f"{node.name}_raw(Parser *p)")
 
     def _should_memoize(self, node: Rule) -> bool:
-        return node.memo and not node.left_recursive
+        return "memo" in node.flags and not node.left_recursive
 
     def _handle_default_rule_body(self, node: Rule, rhs: Rhs, result_type: str) -> None:
         memoize = self._should_memoize(node)

Tools/peg_generator/pegen/grammar.py

@@ -58,11 +58,11 @@ def __iter__(self) -> Iterator[Rule]:
 
 
 class Rule:
-    def __init__(self, name: str, type: str | None, rhs: Rhs, memo: object | None = None):
+    def __init__(self, name: str, type: str | None, rhs: Rhs, flags: frozenset[str] | None = None):
         self.name = name
         self.type = type
         self.rhs = rhs
-        self.memo = bool(memo)
+        self.flags = flags or frozenset()
         self.left_recursive = False
         self.leader = False
 
@@ -135,7 +135,6 @@ def __repr__(self) -> str:
 class Rhs:
     def __init__(self, alts: list[Alt]):
         self.alts = alts
-        self.memo: tuple[str | None, str] | None = None
 
     def __str__(self) -> str:
         return " | ".join(str(alt) for alt in self.alts)
@@ -263,7 +262,6 @@ class Repeat:
 
     def __init__(self, node: Plain):
         self.node = node
-        self.memo: tuple[str | None, str] | None = None
 
     def __iter__(self) -> Iterator[Plain]:
         yield self.node

Tools/peg_generator/pegen/metagrammar.gram

@@ -50,19 +50,21 @@ rules[RuleList]:
     | rule { [rule] }
 
 rule[Rule]:
-    | rulename memoflag? ":" alts NEWLINE INDENT more_alts DEDENT {
-          Rule(rulename[0], rulename[1], Rhs(alts.alts + more_alts.alts), memo=opt) }
-    | rulename memoflag? ":" NEWLINE INDENT more_alts DEDENT {
-          Rule(rulename[0], rulename[1], more_alts, memo=opt) }
-    | rulename memoflag? ":" alts NEWLINE { Rule(rulename[0], rulename[1], alts, memo=opt) }
+    | rulename flags=flags? ":" alts NEWLINE INDENT more_alts DEDENT {
+          Rule(rulename[0], rulename[1], Rhs(alts.alts + more_alts.alts), flags=flags) }
+    | rulename flags=flags? ":" NEWLINE INDENT more_alts DEDENT {
+          Rule(rulename[0], rulename[1], more_alts, flags=flags) }
+    | rulename flags=flags? ":" alts NEWLINE { Rule(rulename[0], rulename[1], alts, flags=flags) }
 
 rulename[RuleName]:
     | NAME annotation { (name.string, annotation) }
     | NAME { (name.string, None) }
 
-# In the future this may return something more complicated
-memoflag[str]:
-    | '(' "memo" ')' { "memo" }
+flags[frozenset[str]]:
+    | '(' a=','.flag+ ')' { frozenset(a) }
+
+flag[str]:
+    | NAME { name.string }
 
 alts[Rhs]:
     | alt "|" alts { Rhs([alt] + alts.alts)}