https://github.com/python/cpython/commit/40795f20ff4ef2054a7f79be537a5ba06759c15f commit: 40795f20ff4ef2054a7f79be537a5ba06759c15f branch: main author: Sergey B Kirpichev <[email protected]> committer: vstinner <[email protected]> date: 2026-06-30T11:57:22+02:00 summary:
gh-121249: Deprecate using F/D type codes in the struct module (#152309) Co-authored-by: Victor Stinner <[email protected]> files: A Misc/NEWS.d/next/Library/2026-06-26-19-01-13.gh-issue-121249.p1SBW0.rst M Doc/deprecations/pending-removal-in-3.21.rst M Doc/deprecations/soft-deprecations.rst M Doc/library/struct.rst M Doc/whatsnew/3.16.rst M Lib/test/test_ctypes/test_byteswap.py M Lib/test/test_memoryview.py M Lib/test/test_struct.py M Modules/_struct.c diff --git a/Doc/deprecations/pending-removal-in-3.21.rst b/Doc/deprecations/pending-removal-in-3.21.rst index 18b89a20e4a2082..dbd73313b4f7779 100644 --- a/Doc/deprecations/pending-removal-in-3.21.rst +++ b/Doc/deprecations/pending-removal-in-3.21.rst @@ -17,3 +17,9 @@ Pending removal in Python 3.21 are not generated by the parser or accepted by the code generator. * The ``dims`` property of ``ast.Tuple`` will be removed in Python 3.21. Use the ``ast.Tuple.elts`` property instead. + +* :mod:`struct`: + + * Soft-deprecated since Python 3.15, using ``'F'`` and ``'D'`` type codes are now + deprecated. These codes will be removed in Python 3.21. Use instead + two-letter forms ``'Zf'`` and ``'Zd'``. diff --git a/Doc/deprecations/soft-deprecations.rst b/Doc/deprecations/soft-deprecations.rst index d1dd2b2d8c520d6..a270052788ef2a1 100644 --- a/Doc/deprecations/soft-deprecations.rst +++ b/Doc/deprecations/soft-deprecations.rst @@ -19,8 +19,3 @@ There are no plans to remove :term:`soft deprecated` APIs. (Contributed by Gregory P. Smith in :gh:`86519` and Hugo van Kemenade in :gh:`148100`.) - -* Using ``'F'`` and ``'D'`` format type codes of the :mod:`struct` module - now are :term:`soft deprecated` in favor of two-letter forms ``'Zf'`` - and ``'Zd'``. - (Contributed by Sergey B Kirpichev in :gh:`121249`.) diff --git a/Doc/library/struct.rst b/Doc/library/struct.rst index 775e5b2074851b7..ed5a719028d60ef 100644 --- a/Doc/library/struct.rst +++ b/Doc/library/struct.rst @@ -283,7 +283,9 @@ platform-dependent. .. versionchanged:: 3.15 Added support for the ``'Zf'`` and ``'Zd'`` formats. - ``'F'`` and ``'D'`` formats are :term:`soft deprecated`. + +.. versionchanged:: 3.16 + ``'F'`` and ``'D'`` formats are deprecated. .. seealso:: diff --git a/Doc/whatsnew/3.16.rst b/Doc/whatsnew/3.16.rst index e215d4ddfdf41b7..1a73a79a58b78b1 100644 --- a/Doc/whatsnew/3.16.rst +++ b/Doc/whatsnew/3.16.rst @@ -550,6 +550,13 @@ New deprecations 3.9, now issues a deprecation warning on use. This property is slated for removal in 3.21. Use ``ast.Tuple.elts`` instead. +* :mod:`struct`: + + * Soft-deprecated since Python 3.15, using ``'F'`` and ``'D'`` type codes are now + deprecated. These codes will be removed in Python 3.21. Use instead + two-letter forms ``'Zf'`` and ``'Zd'``. + (Contributed by Sergey B Kirpichev in :gh:`121249`.) + .. Add deprecations above alphabetically, not here at the end. .. include:: ../deprecations/pending-removal-in-3.17.rst diff --git a/Lib/test/test_ctypes/test_byteswap.py b/Lib/test/test_ctypes/test_byteswap.py index 6a1bae14773d277..1351b3e6bd2fa46 100644 --- a/Lib/test/test_ctypes/test_byteswap.py +++ b/Lib/test/test_ctypes/test_byteswap.py @@ -178,14 +178,14 @@ def test_endian_float_complex(self): self.assertIs(c_float_complex.__ctype_le__.__ctype_be__, c_float_complex) s = c_float_complex(math.pi+1j) - self.assertEqual(bin(struct.pack("F", math.pi+1j)), bin(s)) + self.assertEqual(bin(struct.pack("Zf", math.pi+1j)), bin(s)) self.assertAlmostEqual(s.value, math.pi+1j, places=6) s = c_float_complex.__ctype_le__(math.pi+1j) self.assertAlmostEqual(s.value, math.pi+1j, places=6) - self.assertEqual(bin(struct.pack("<F", math.pi+1j)), bin(s)) + self.assertEqual(bin(struct.pack("<Zf", math.pi+1j)), bin(s)) s = c_float_complex.__ctype_be__(math.pi+1j) self.assertAlmostEqual(s.value, math.pi+1j, places=6) - self.assertEqual(bin(struct.pack(">F", math.pi+1j)), bin(s)) + self.assertEqual(bin(struct.pack(">Zf", math.pi+1j)), bin(s)) @unittest.skipUnless(hasattr(ctypes, 'c_double_complex'), "No complex types") def test_endian_double_complex(self): @@ -199,14 +199,14 @@ def test_endian_double_complex(self): self.assertIs(c_double_complex.__ctype_le__.__ctype_be__, c_double_complex) s = c_double_complex(math.pi+1j) - self.assertEqual(bin(struct.pack("D", math.pi+1j)), bin(s)) + self.assertEqual(bin(struct.pack("Zd", math.pi+1j)), bin(s)) self.assertAlmostEqual(s.value, math.pi+1j, places=6) s = c_double_complex.__ctype_le__(math.pi+1j) self.assertAlmostEqual(s.value, math.pi+1j, places=6) - self.assertEqual(bin(struct.pack("<D", math.pi+1j)), bin(s)) + self.assertEqual(bin(struct.pack("<Zd", math.pi+1j)), bin(s)) s = c_double_complex.__ctype_be__(math.pi+1j) self.assertAlmostEqual(s.value, math.pi+1j, places=6) - self.assertEqual(bin(struct.pack(">D", math.pi+1j)), bin(s)) + self.assertEqual(bin(struct.pack(">Zd", math.pi+1j)), bin(s)) def test_endian_other(self): self.assertIs(c_byte.__ctype_le__, c_byte) diff --git a/Lib/test/test_memoryview.py b/Lib/test/test_memoryview.py index f71b6f53486509b..df5ab9f2c879ca3 100644 --- a/Lib/test/test_memoryview.py +++ b/Lib/test/test_memoryview.py @@ -717,8 +717,8 @@ def test_half_float(self): self.assertListEqual(half_view.tolist(), float_view.tolist()) def test_complex_types(self): - float_complex_data = struct.pack('FFF', 0.0, -1.5j, 1+2j) - double_complex_data = struct.pack('DDD', 0.0, -1.5j, 1+2j) + float_complex_data = struct.pack('ZfZfZf', 0.0, -1.5j, 1+2j) + double_complex_data = struct.pack('ZdZdZd', 0.0, -1.5j, 1+2j) float_complex_view = memoryview(float_complex_data).cast('Zf') double_complex_view = memoryview(double_complex_data).cast('Zd') self.assertEqual(float_complex_view.nbytes * 2, double_complex_view.nbytes) diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py index edd85df633fc3bb..f9803abb3db91fa 100644 --- a/Lib/test/test_struct.py +++ b/Lib/test/test_struct.py @@ -7,6 +7,7 @@ import unittest import struct import sys +import warnings import weakref from test import support @@ -995,14 +996,26 @@ def test_c_complex_round_trip(self): values = [complex(*_) for _ in combinations([1, -1, 0.0, -0.0, 2, -3, INF, -INF, NAN], 2)] for z in values: - for f in [ - 'F', 'D', 'Zf', 'Zd', - '>F', '>D', '>Zf', '>Zd', - '<F', '<D', '<Zf', '<Zd', - ]: + for f in ['Zf', 'Zd', '>Zf', '>Zd', '<Zf', '<Zd']: with self.subTest(z=z, format=f): round_trip = struct.unpack(f, struct.pack(f, z))[0] self.assertComplexesAreIdentical(z, round_trip) + z = 1+1j + for fmt in ['F', 'D', '>F', '>D', '<F', '<D']: + with self.subTest(format=fmt): + with warnings.catch_warnings(): + warnings.simplefilter("error", DeprecationWarning) + self.assertRaises(DeprecationWarning, struct.pack, fmt, z) + with warnings.catch_warnings(): + with self.assertWarns(DeprecationWarning): + b = struct.pack(fmt, z) + + with warnings.catch_warnings(): + warnings.simplefilter("error", DeprecationWarning) + self.assertRaises(DeprecationWarning, struct.unpack, fmt, b) + with self.assertWarns(DeprecationWarning): + round_trip = struct.unpack(fmt, b)[0] + self.assertComplexesAreIdentical(z, round_trip) @unittest.skipIf( support.is_android or support.is_apple_mobile, diff --git a/Misc/NEWS.d/next/Library/2026-06-26-19-01-13.gh-issue-121249.p1SBW0.rst b/Misc/NEWS.d/next/Library/2026-06-26-19-01-13.gh-issue-121249.p1SBW0.rst new file mode 100644 index 000000000000000..0e676e7774d1d7a --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-06-26-19-01-13.gh-issue-121249.p1SBW0.rst @@ -0,0 +1 @@ +Deprecate using ``'F'`` and ``'D'`` type codes in the :mod:`struct` module. diff --git a/Modules/_struct.c b/Modules/_struct.c index 8c611a708d02a9d..6bf3993439cf1d7 100644 --- a/Modules/_struct.c +++ b/Modules/_struct.c @@ -1697,6 +1697,21 @@ prepare_s(PyStructObject *self, PyObject *format) if (e == NULL) return -1; + if (strcmp(e->format, "F") == 0) { + if (PyErr_WarnEx(PyExc_DeprecationWarning, + "The 'F' type code is deprecated, use 'Zf'", 1)) + { + return -1; + } + } + if (strcmp(e->format, "D") == 0) { + if (PyErr_WarnEx(PyExc_DeprecationWarning, + "The 'D' type code is deprecated, use 'Zd'", 1)) + { + return -1; + } + } + switch (c) { case 's': _Py_FALLTHROUGH; case 'p': @@ -2065,6 +2080,20 @@ s_unpack_internal(PyStructObject *soself, const char *startfrom, } v = PyBytes_FromStringAndSize(res + 1, n); } else { + if (strcmp(e->format, "F") == 0) { + if (PyErr_WarnEx(PyExc_DeprecationWarning, + "The 'F' type code is deprecated, use 'Zf'", 1)) + { + goto fail; + } + } + if (strcmp(e->format, "D") == 0) { + if (PyErr_WarnEx(PyExc_DeprecationWarning, + "The 'D' type code is deprecated, use 'Zd'", 1)) + { + goto fail; + } + } v = e->unpack(state, res, e); } if (v == NULL) _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
