Merge branch 'main' into doc-ob-mutex-warning

Author: overlorde

Doc/library/stdtypes.rst

@@ -2180,7 +2180,18 @@ expression support in the :mod:`re` module).
    Return ``True`` if all characters in the string are alphanumeric and there is at
    least one character, ``False`` otherwise.  A character ``c`` is alphanumeric if one
    of the following returns ``True``: ``c.isalpha()``, ``c.isdecimal()``,
-   ``c.isdigit()``, or ``c.isnumeric()``.
+   ``c.isdigit()``, or ``c.isnumeric()``. For example::
+
+   .. doctest::
+
+      >>> 'abc123'.isalnum()
+      True
+      >>> 'abc123!@#'.isalnum()
+      False
+      >>> ''.isalnum()
+      False
+      >>> ' '.isalnum()
+      False
 
 
 .. method:: str.isalpha()
@@ -2472,6 +2483,19 @@ expression support in the :mod:`re` module).
    after the separator.  If the separator is not found, return a 3-tuple containing
    the string itself, followed by two empty strings.
 
+   For example:
+
+   .. doctest::
+
+      >>> 'Monty Python'.partition(' ')
+      ('Monty', ' ', 'Python')
+      >>> "Monty Python's Flying Circus".partition(' ')
+      ('Monty', ' ', "Python's Flying Circus")
+      >>> 'Monty Python'.partition('-')
+      ('Monty Python', '', '')
+
+   See also :meth:`rpartition`.
+
 
 .. method:: str.removeprefix(prefix, /)
 

Lib/test/test_capi/test_opt.py

@@ -1986,6 +1986,23 @@ def f(n):
         self.assertNotIn("_GUARD_NOS_TUPLE", uops)
         self.assertIn("_BINARY_OP_SUBSCR_TUPLE_INT", uops)
 
+    def test_remove_guard_for_known_type_slice(self):
+        def f(n):
+            x = 0
+            for _ in range(n):
+                l = [1, 2, 3]
+                slice_obj = slice(0, 1)
+                x += l[slice_obj][0] # guarded
+                x += l[slice_obj][0] # unguarded
+            return x
+        res, ex = self._run_with_optimizer(f, TIER2_THRESHOLD)
+        self.assertEqual(res, TIER2_THRESHOLD * 2)
+        uops = get_opnames(ex)
+
+        count = count_ops(ex, "_GUARD_TOS_SLICE")
+        self.assertEqual(count, 1)
+        self.assertIn("_BINARY_OP_SUBSCR_LIST_INT", uops)
+
     def test_remove_guard_for_tuple_bounds_check(self):
         def f(n):
             x = 0

Misc/NEWS.d/next/Core_and_Builtins/2026-02-04-12-19-48.gh-issue-131798.My5jLy.rst

@@ -0,0 +1 @@
+Optimise ``_GUARD_TOS_SLICE`` in the JIT.

Python/optimizer_bytecodes.c

@@ -1374,6 +1374,13 @@ dummy_func(void) {
         }
     }
 
+    op(_GUARD_TOS_SLICE, (tos -- tos)) {
+        if (sym_matches_type(tos, &PySlice_Type)) {
+            ADD_OP(_NOP, 0, 0);
+        }
+        sym_set_type(tos, &PySlice_Type);
+    }
+
     op(_GUARD_NOS_NULL, (null, unused -- null, unused)) {
         if (sym_is_null(null)) {
             ADD_OP(_NOP, 0, 0);