gh-129813, PEP 782: Soft deprecate _PyBytes_Resize() (#138964)

Soft deprecate _PyBytes_Resize() and
PyBytes_FromStringAndSize(NULL, size).

Author: vstinner

Doc/c-api/bytes.rst

@@ -47,6 +47,10 @@ called with a non-bytes parameter.
    *len* on success, and ``NULL`` on failure.  If *v* is ``NULL``, the contents of
    the bytes object are uninitialized.
 
+   .. deprecated:: 3.15
+      ``PyBytes_FromStringAndSize(NULL, len)`` is :term:`soft deprecated`,
+      use the :c:type:`PyBytesWriter` API instead.
+
 
 .. c:function:: PyObject* PyBytes_FromFormat(const char *format, ...)
 
@@ -220,6 +224,11 @@ called with a non-bytes parameter.
    *\*bytes* is set to ``NULL``, :exc:`MemoryError` is set, and ``-1`` is
    returned.
 
+   .. deprecated:: 3.15
+      The function is :term:`soft deprecated`,
+      use the :c:type:`PyBytesWriter` API instead.
+
+
 PyBytesWriter
 -------------
 

Doc/whatsnew/3.15.rst

@@ -774,6 +774,11 @@ Deprecated C APIs
   signed integer type of the same size is now deprecated.
   (Contributed by Serhiy Storchaka in :gh:`132629`.)
 
+* :c:func:`PyBytes_FromStringAndSize(NULL, len) <PyBytes_FromStringAndSize>`
+  and :c:func:`_PyBytes_Resize` are :term:`soft deprecated`,
+  use the :c:type:`PyBytesWriter` API instead.
+  (Contributed by Victor Stinner in :gh:`129813`.)
+
 * Deprecate :c:member:`~PyComplexObject.cval` field of the the
   :c:type:`PyComplexObject` type.
   Use :c:func:`PyComplex_AsCComplex` and :c:func:`PyComplex_FromCComplex`