gh-127691: add type checks when using PyUnicodeError objects

Doc/whatsnew/3.14.rst

@@ -1027,6 +1027,12 @@ New features
 * Add :c:func:`PyUnstable_Object_EnableDeferredRefcount` for enabling
   deferred reference counting, as outlined in :pep:`703`.
 
+* The :ref:`Unicode Exception Objects <unicodeexceptions>` C API
+  now raises :exc:`TypeError` if its exception argument is not an
+  :exc:`UnicodeError`.
+  (Contributed by Bénédikt Tran in :gh:`127691`.)
+
+
 Porting to Python 3.14
 ----------------------
 

Misc/NEWS.d/next/C_API/2024-12-06-16-53-34.gh-issue-127691.k_Jitp.rst

@@ -0,0 +1,4 @@
+The :ref:`Unicode Exception Objects <unicodeexceptions>` C API now
+type-checks its exception argument, raising a :exc:`TypeError` if
+the latter is not an instance of :exc:`UnicodeError`.
+Patch by Bénédikt Tran.