From 43cf286df529aa10b1650630a4156d286eb4ce4b Mon Sep 17 00:00:00 2001 From: Ramin Farajpour Cami Date: Sat, 7 Mar 2026 17:01:45 +0330 Subject: [PATCH] gh-145623: Fix crashes on uninitialized struct.Struct objects (gh-145624) --- Lib/test/test_struct.py | 2 ++ .../Library/2026-03-07-15-00-00.gh-issue-145623.2Y7LzT.rst | 3 +++ Modules/_struct.c | 2 ++ 3 files changed, 7 insertions(+) create mode 100644 Misc/NEWS.d/next/Library/2026-03-07-15-00-00.gh-issue-145623.2Y7LzT.rst diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py index 2b8d19ac966444..4a7706ff4320cb 100644 --- a/Lib/test/test_struct.py +++ b/Lib/test/test_struct.py @@ -836,6 +836,8 @@ def test_operations_on_half_initialized_Struct(self): self.assertRaises(RuntimeError, S.unpack, spam) self.assertRaises(RuntimeError, S.unpack_from, spam) self.assertRaises(RuntimeError, getattr, S, 'format') + self.assertRaises(RuntimeError, S.__sizeof__) + self.assertRaises(RuntimeError, repr, S) self.assertEqual(S.size, -1) diff --git a/Misc/NEWS.d/next/Library/2026-03-07-15-00-00.gh-issue-145623.2Y7LzT.rst b/Misc/NEWS.d/next/Library/2026-03-07-15-00-00.gh-issue-145623.2Y7LzT.rst new file mode 100644 index 00000000000000..77b43e79e35860 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-03-07-15-00-00.gh-issue-145623.2Y7LzT.rst @@ -0,0 +1,3 @@ +Fix crash in :mod:`struct` when calling :func:`repr` or +``__sizeof__()`` on an uninitialized :class:`struct.Struct` +object created via ``Struct.__new__()`` without calling ``__init__()``. diff --git a/Modules/_struct.c b/Modules/_struct.c index 61d3ab0d7a474c..0ed1c517aed67d 100644 --- a/Modules/_struct.c +++ b/Modules/_struct.c @@ -2410,6 +2410,7 @@ static PyObject * s_sizeof(PyObject *op, PyObject *Py_UNUSED(dummy)) { PyStructObject *self = PyStructObject_CAST(op); + ENSURE_STRUCT_IS_READY(self); size_t size = _PyObject_SIZE(Py_TYPE(self)) + sizeof(formatcode); for (formatcode *code = self->s_codes; code->fmtdef != NULL; code++) { size += sizeof(formatcode); @@ -2421,6 +2422,7 @@ static PyObject * s_repr(PyObject *op) { PyStructObject *self = PyStructObject_CAST(op); + ENSURE_STRUCT_IS_READY(self); PyObject* fmt = PyUnicode_FromStringAndSize( PyBytes_AS_STRING(self->s_format), PyBytes_GET_SIZE(self->s_format)); if (fmt == NULL) {