Import CPython 3.14.6+ stable branch (2026-07-17)

Summary:
Imported python/cpython `3.14.6+` from upstream rev [`890bd0e`](https://www.github.com/python/cpython/commit/890bd0ed9130c8baa1e5a29fcfac266b1504889e) (committed 2026-07-17 02:50:00+00:00).

# Commit Info

- Base: (`3.14.6+`) - [`9b33b25`](https://www.github.com/python/cpython/commit/9b33b258aa582f18439acb4e9a36e4e755ab106a) (commit date: 2026-07-15 18:13:38+00:00)
- Imported: (`3.14.6+`) - [`890bd0e`](https://www.github.com/python/cpython/commit/890bd0ed9130c8baa1e5a29fcfac266b1504889e) (commit date: 2026-07-17 02:50:00+00:00)

# Noteworthy file changes

- Low-signal files (1 added) (NEWS.d, docs, .github)

Complete list of added/removed files: https://www.internalfb.com/intern/everpaste/?color=0&handle=GOoduSR6rh-Wz8YDAELdSg7YGjwZbr0LAAAz

Reviewed By: KasraGhodsi

Differential Revision: D112527225

fbshipit-source-id: 56d46ebcf67fb68456e1c3779dff15f8e88a7dc3

Author: generatedunixname1734921407115435

Doc/library/typing.rst

@@ -2099,7 +2099,7 @@ without the dedicated syntax, as documented below.
 
       Support for default values was added.
 
-.. class:: ParamSpec(name, *, bound=None, covariant=False, contravariant=False, default=typing.NoDefault)
+.. class:: ParamSpec(name, *, bound=None, covariant=False, contravariant=False, infer_variance=False, default=typing.NoDefault)
 
    Parameter specification variable.  A specialized version of
    :ref:`type variables <typevar>`.

Misc/NEWS.d/next/Core_and_Builtins/2026-04-29-15-10-59.gh-issue-149162.BPPyrq.rst

@@ -0,0 +1,3 @@
+Fix a potential deadlock in :c:func:`PyUnicode_InternFromString` and other
+interning functions in the :term:`free-threaded build` when called from C++
+static local initializers.

Objects/unicodeobject.c

@@ -113,7 +113,9 @@ NOTE: In the interpreter's initialization phase, some globals are currently
 #endif
 
 #ifdef Py_GIL_DISABLED
-#  define LOCK_INTERNED(interp) PyMutex_Lock(&_Py_INTERP_CACHED_OBJECT(interp, interned_mutex))
+#  define LOCK_INTERNED(interp) \
+    PyMutex_LockFlags(&_Py_INTERP_CACHED_OBJECT(interp, interned_mutex), \
+                      _Py_LOCK_DONT_DETACH)
 #  define UNLOCK_INTERNED(interp) PyMutex_Unlock(&_Py_INTERP_CACHED_OBJECT(interp, interned_mutex))
 #else
 #  define LOCK_INTERNED(interp)