Sync pre-release CPython main branch from GitHub (2026-03-13)

Summary:
Imported python/cpython `3.15.0a7+` from upstream rev [`0adc728`](https://www.github.com/python/cpython/commit/0adc7289c3ab097b5608c0d288d91e1f5f236469) (committed 2026-03-13 01:53:29+00:00).

# Commit Info

Base: (`3.15.0a7+`) - [`d19de37`](https://www.github.com/python/cpython/commit/d19de375a204c74ab5f3a28ec42335bae139033d) (commit date: 2026-03-11 21:08:18+00:00)
Imported: (`3.15.0a7+`) - [`0adc728`](https://www.github.com/python/cpython/commit/0adc7289c3ab097b5608c0d288d91e1f5f236469) (commit date: 2026-03-13 01:53:29+00:00)

# Files added

```
Doc/data/threadsafety.dat
Misc/NEWS.d/next/Build/2026-03-11-11-58-42.gh-issue-145801.iCXa3v.rst
Misc/NEWS.d/next/Core_and_Builtins/2025-11-02-16-23-17.gh-issue-140594.YIWUpl.rst
Misc/NEWS.d/next/Core_and_Builtins/2026-03-10-12-52-06.gh-issue-145685.80B7gK.rst
Misc/NEWS.d/next/Library/2026-01-10-16-23-21.gh-issue-143715.HZrfSA.rst
Misc/NEWS.d/next/Library/2026-02-11-21-01-30.gh-issue-144259.OAhOR8.rst
Misc/NEWS.d/next/Library/2026-03-03-23-21-40.gh-issue-145446.0c-TJX.rst
Misc/NEWS.d/next/Library/2026-03-10-01-48-12.gh-issue-145717.dPc0Rt.rst
Misc/NEWS.d/next/Windows/2025-10-19-23-44-46.gh-issue-140131.AABF2k.rst
```

Differential Revision: D96427231

fbshipit-source-id: 8fff5233559b1a601a3c49775f092a6bb15a736c

Author: generatedunixname1734921407115435

cinderx/Interpreter/3.15/Includes/generated_cases.c.h

@@ -827,12 +827,10 @@
                 PyObject *list = PyStackRef_AsPyObjectBorrow(list_st);
                 assert(PyLong_CheckExact(sub));
                 assert(PyList_CheckExact(list));
-                if (!_PyLong_IsNonNegativeCompact((PyLongObject *)sub)) {
-                    UPDATE_MISS_STATS(BINARY_OP);
-                    assert(_PyOpcode_Deopt[opcode] == (BINARY_OP));
-                    JUMP_TO_PREDICTED(BINARY_OP);
+                Py_ssize_t index = _PyLong_CompactValue((PyLongObject *)sub);
+                if (index < 0) {
+                    index += PyList_GET_SIZE(list);
                 }
-                Py_ssize_t index = ((PyLongObject*)sub)->long_value.ob_digit[0];
                 #ifdef Py_GIL_DISABLED
                 _PyFrame_SetStackPointer(frame, stack_pointer);
                 PyObject *res_o = _PyList_GetItemRef((PyListObject*)list, index);
@@ -842,15 +840,13 @@
                     assert(_PyOpcode_Deopt[opcode] == (BINARY_OP));
                     JUMP_TO_PREDICTED(BINARY_OP);
                 }
-                STAT_INC(BINARY_OP, hit);
                 res = PyStackRef_FromPyObjectSteal(res_o);
                 #else
-                if (index >= PyList_GET_SIZE(list)) {
+                if (index < 0 || index >= PyList_GET_SIZE(list)) {
                     UPDATE_MISS_STATS(BINARY_OP);
                     assert(_PyOpcode_Deopt[opcode] == (BINARY_OP));
                     JUMP_TO_PREDICTED(BINARY_OP);
                 }
-                STAT_INC(BINARY_OP, hit);
                 PyObject *res_o = PyList_GET_ITEM(list, index);
                 assert(res_o != NULL);
                 res = PyStackRef_FromPyObjectNew(res_o);
@@ -12463,21 +12459,25 @@
             next_instr += 5;
             INSTRUCTION_STATS(STORE_ATTR_INSTANCE_VALUE);
             static_assert(INLINE_CACHE_ENTRIES_STORE_ATTR == 4, "incorrect cache size");
-            _PyStackRef owner;
             _PyStackRef value;
+            _PyStackRef owner;
             _PyStackRef o;
             /* Skip 1 cache entry */
-            // _GUARD_TYPE_VERSION_AND_LOCK
+            // _LOCK_OBJECT
             {
-                owner = stack_pointer[-1];
-                uint32_t type_version = read_u32(&this_instr[2].cache);
-                PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
-                assert(type_version != 0);
-                if (!LOCK_OBJECT(owner_o)) {
+                value = stack_pointer[-1];
+                if (!LOCK_OBJECT(PyStackRef_AsPyObjectBorrow(value))) {
                     UPDATE_MISS_STATS(STORE_ATTR);
                     assert(_PyOpcode_Deopt[opcode] == (STORE_ATTR));
                     JUMP_TO_PREDICTED(STORE_ATTR);
                 }
+            }
+            // _GUARD_TYPE_VERSION_LOCKED
+            {
+                owner = value;
+                uint32_t type_version = read_u32(&this_instr[2].cache);
+                PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
+                assert(type_version != 0);
                 PyTypeObject *tp = Py_TYPE(owner_o);
                 if (FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version) {
                     UNLOCK_OBJECT(owner_o);
@@ -13101,18 +13101,17 @@
                 PyObject *list = PyStackRef_AsPyObjectBorrow(list_st);
                 assert(PyLong_CheckExact(sub));
                 assert(PyList_CheckExact(list));
-                if (!_PyLong_IsNonNegativeCompact((PyLongObject *)sub)) {
-                    UPDATE_MISS_STATS(STORE_SUBSCR);
-                    assert(_PyOpcode_Deopt[opcode] == (STORE_SUBSCR));
-                    JUMP_TO_PREDICTED(STORE_SUBSCR);
-                }
-                Py_ssize_t index = ((PyLongObject*)sub)->long_value.ob_digit[0];
+                Py_ssize_t index = _PyLong_CompactValue((PyLongObject *)sub);
                 if (!LOCK_OBJECT(list)) {
                     UPDATE_MISS_STATS(STORE_SUBSCR);
                     assert(_PyOpcode_Deopt[opcode] == (STORE_SUBSCR));
                     JUMP_TO_PREDICTED(STORE_SUBSCR);
                 }
-                if (index >= PyList_GET_SIZE(list)) {
+                Py_ssize_t len = PyList_GET_SIZE(list);
+                if (index < 0) {
+                    index += len;
+                }
+                if (index < 0 || index >= len) {
                     UNLOCK_OBJECT(list);
                     if (true) {
                         UPDATE_MISS_STATS(STORE_SUBSCR);

cinderx/UpstreamBorrow/borrowed-3.15.gen_cached.c

@@ -2181,8 +2181,8 @@ int init_upstream_borrow(void) {
     MCACHE_HASH(FT_ATOMIC_LOAD_UINT_RELAXED((type)->tp_version_tag),   \
                 ((Py_ssize_t)(name)) >> 3)
 #define MCACHE_CACHEABLE_NAME(name)                             \
-        PyUnicode_CheckExact(name) &&                           \
-        (PyUnicode_GET_LENGTH(name) <= MCACHE_MAX_ATTR_SIZE)
+        (PyUnicode_CheckExact(name) &&                           \
+         (PyUnicode_GET_LENGTH(name) <= MCACHE_MAX_ATTR_SIZE))
 #define NEXT_VERSION_TAG(interp) \
     (interp)->types.next_version_tag
 #ifdef Py_GIL_DISABLED