pending-removal-in-3.19.rst

Pending removal in Python 3.19

• :mod:`ctypes`:

  • Implicitly switching to the MSVC-compatible struct layout by setting :attr:`~ctypes.Structure._pack_` but not :attr:`~ctypes.Structure._layout_` on non-Windows platforms.

• :mod:`hashlib`:

  • In hash function constructors such as :func:`~hashlib.new` or the direct hash-named constructors such as :func:`~hashlib.md5` and :func:`~hashlib.sha256`, their optional initial data parameter could also be passed a keyword argument named data= or string= in various :mod:`!hashlib` implementations.

    Support for the string keyword argument name is now deprecated and slated for removal in Python 3.19.

    Before Python 3.13, the string keyword parameter was not correctly supported depending on the backend implementation of hash functions. Prefer passing the initial data as a positional argument for maximum backwards compatibility.

• :mod:`http.cookies`:

  • :meth:`http.cookies.BaseCookie.js_output` is deprecated and will be removed in Python 3.19.

    This method generates a JavaScript snippet to set cookies in the browser, which is no longer considered a standard or recommended approach. Use :meth:`~http.cookies.BaseCookie.output` instead to generate HTTP headers.