gh-121249: deprecate support for F/D type codes in the struct module

Doc/deprecations/pending-removal-in-3.17.rst

@@ -37,6 +37,7 @@ Pending removal in Python 3.17
     is deprecated and scheduled for removal in Python 3.17.
     (Contributed by Stan Ulbrych in :gh:`136702`.)
 
+
 * :mod:`typing`:
 
   - Before Python 3.14, old-style unions were implemented using the private class

Doc/deprecations/pending-removal-in-3.20.rst

@@ -1,12 +1,18 @@
 Pending removal in Python 3.20
 ------------------------------
 
-* Calling the ``__new__()`` method of :class:`struct.Struct` without the
-  *format* argument is deprecated and will be removed in Python 3.20.  Calling
-  :meth:`~object.__init__` method on initialized :class:`~struct.Struct`
-  objects is deprecated and will be removed in Python 3.20.
+* :mod:`struct`:
+
+  - Calling the ``__new__()`` method of :class:`struct.Struct` without the
+    *format* argument is deprecated and will be removed in Python 3.20.  Calling
+    :meth:`~object.__init__` method on initialized :class:`~struct.Struct`
+    objects is deprecated and will be removed in Python 3.20.
+    (Contributed by Sergey B Kirpichev and Serhiy Storchaka in :gh:`143715`.)
+
+  - Support for ``'F'`` and ``'D'`` format type codes (the :c:expr:`float
+    complex` and :c:expr:`double complex` C types, respectively)
+    (Contributed by Sergey B Kirpichev in :gh:`121249`.)
 
-  (Contributed by Sergey B Kirpichev and Serhiy Storchaka in :gh:`143715`.)
 
 * The ``__version__``, ``version`` and ``VERSION`` attributes have been
   deprecated in these standard library modules and will be removed in

Doc/library/struct.rst

@@ -260,10 +260,6 @@ platform-dependent.
 +--------+--------------------------+--------------------+----------------+------------+
 | ``d``  | :c:expr:`double`         | float              | 8              | \(4)       |
 +--------+--------------------------+--------------------+----------------+------------+
-| ``F``  | :c:expr:`float complex`  | complex            | 8              | \(10)      |
-+--------+--------------------------+--------------------+----------------+------------+
-| ``D``  | :c:expr:`double complex` | complex            | 16             | \(10)      |
-+--------+--------------------------+--------------------+----------------+------------+
 | ``Zf`` | :c:expr:`float complex`  | complex            | 8              | \(10)      |
 +--------+--------------------------+--------------------+----------------+------------+
 | ``Zd`` | :c:expr:`double complex` | complex            | 16             | \(10)      |
@@ -287,6 +283,9 @@ platform-dependent.
 .. versionchanged:: next
    Added support for the ``'Zf'`` and ``'Zd'`` formats.
 
+.. deprecated-removed:: 3.15 3.20
+   Support for the ``'F'`` and ``'D'`` format codes.
+
 .. seealso::
 
    The :mod:`array` and :ref:`ctypes <ctypes-fundamental-data-types>` modules,
@@ -376,13 +375,15 @@ Notes:
    are accepted.
 
 (10)
-   For the ``'F'`` and ``'D'`` format characters, the packed representation uses
+   For the ``'Zf'`` and ``'Zd'`` format characters, the packed representation uses
    the IEEE 754 binary32 and binary64 format for components of the complex
    number, regardless of the floating-point format used by the platform.
-   Note that complex types (``F``/``Zf`` and ``D``/``Zd``) are available unconditionally,
+   Note that complex types are available unconditionally,
    despite complex types being an optional feature in C.
    As specified in the C11 standard, each complex type is represented by a
    two-element C array containing, respectively, the real and imaginary parts.
+   The ``'F'`` and ``'D'`` (for ``'Zf'`` and ``'Zd'``, respectively) format
+   characters are supported for compatibility.
 
 
 A format character may be preceded by an integral repeat count.  For example,

Doc/whatsnew/3.15.rst

@@ -2054,6 +2054,11 @@ New deprecations
 
     (Contributed by Sergey B Kirpichev and Serhiy Storchaka in :gh:`143715`.)
 
+  - Support for ``'F'`` and ``'D'`` format type codes (the :c:expr:`float
+    complex` and :c:expr:`double complex` C types, respectively)
+    (Contributed by Sergey B Kirpichev in :gh:`121249`.)
+
+
 * :mod:`typing`:
 
   * The following statements now cause ``DeprecationWarning``\ s to be emitted

Misc/NEWS.d/next/Library/2026-05-04-05-22-48.gh-issue-121249.XN06Fd.rst

@@ -0,0 +1,2 @@
+Deprecate support for complex types in the :mod:`struct` module (formatting
+characters ``'F'`` and ``'D'`` respectively).