diff --git a/Include/internal/pycore_typeobject.h b/Include/internal/pycore_typeobject.h index a6562f7f9ba74e..164b243dae7806 100644 --- a/Include/internal/pycore_typeobject.h +++ b/Include/internal/pycore_typeobject.h @@ -199,6 +199,7 @@ extern PyObject * _PyType_GetMRO(PyTypeObject *type); extern PyObject* _PyType_GetSubclasses(PyTypeObject *); extern int _PyType_HasSubclasses(PyTypeObject *); PyAPI_FUNC(PyObject *) _PyType_GetModuleByDef2(PyTypeObject *, PyTypeObject *, PyModuleDef *); +PyAPI_FUNC(PyObject *) _PyType_GetModuleByDef3(PyTypeObject *, PyTypeObject *, PyTypeObject *, PyModuleDef *); // PyType_Ready() must be called if _PyType_IsReady() is false. // See also the Py_TPFLAGS_READY flag. diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py index d1e7e69e7e951b..c4d05f87a8df22 100644 --- a/Lib/test/test_decimal.py +++ b/Lib/test/test_decimal.py @@ -4458,6 +4458,15 @@ def test_implicit_context(self): self.assertIs(Decimal("NaN").fma(7, 1).is_nan(), True) # three arg power self.assertEqual(pow(Decimal(10), 2, 7), 2) + if self.decimal == C: + self.assertEqual(pow(10, Decimal(2), 7), 2) + self.assertEqual(pow(10, 2, Decimal(7)), 2) + else: + # XXX: Three-arg power doesn't use __rpow__. + self.assertRaises(TypeError, pow, 10, Decimal(2), 7) + # XXX: There is no special method to dispatch on the + # third arg of three-arg power. + self.assertRaises(TypeError, pow, 10, 2, Decimal(7)) # exp self.assertEqual(Decimal("1.01").exp(), 3) # is_normal diff --git a/Misc/NEWS.d/next/Library/2025-02-17-21-16-51.gh-issue-130230.9ta9P9.rst b/Misc/NEWS.d/next/Library/2025-02-17-21-16-51.gh-issue-130230.9ta9P9.rst new file mode 100644 index 00000000000000..20327fd5f25b43 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-02-17-21-16-51.gh-issue-130230.9ta9P9.rst @@ -0,0 +1 @@ +Fix crash in :func:`pow` with only :class:`~decimal.Decimal` third argument. diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c index 29ae5f402a06f9..d1fbfd7d30317b 100644 --- a/Modules/_decimal/_decimal.c +++ b/Modules/_decimal/_decimal.c @@ -140,6 +140,15 @@ find_state_left_or_right(PyObject *left, PyObject *right) return get_module_state(mod); } +static inline decimal_state * +find_state_ternary(PyObject *left, PyObject *right, PyObject *modulus) +{ + PyObject *mod = _PyType_GetModuleByDef3(Py_TYPE(left), Py_TYPE(right), Py_TYPE(modulus), + &_decimal_module); + assert(mod != NULL); + return get_module_state(mod); +} + #if !defined(MPD_VERSION_HEX) || MPD_VERSION_HEX < 0x02050000 #error "libmpdec version >= 2.5.0 required" @@ -4305,7 +4314,7 @@ nm_mpd_qpow(PyObject *base, PyObject *exp, PyObject *mod) PyObject *context; uint32_t status = 0; - decimal_state *state = find_state_left_or_right(base, exp); + decimal_state *state = find_state_ternary(base, exp, mod); CURRENT_CONTEXT(state, context); CONVERT_BINOP(&a, &b, base, exp, context); diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 57e03c669d9141..c84841070555d1 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -5038,6 +5038,26 @@ _PyType_GetModuleByDef2(PyTypeObject *left, PyTypeObject *right, return module; } +PyObject * +_PyType_GetModuleByDef3(PyTypeObject *left, PyTypeObject *right, PyTypeObject *third, + PyModuleDef *def) +{ + PyObject *module = get_module_by_def(left, def); + if (module == NULL) { + module = get_module_by_def(right, def); + if (module == NULL) { + module = get_module_by_def(third, def); + if (module == NULL) { + PyErr_Format( + PyExc_TypeError, + "PyType_GetModuleByDef: No superclass of '%s', '%s' nor '%s' has " + "the given module", left->tp_name, right->tp_name, third->tp_name); + } + } + } + return module; +} + void * PyObject_GetTypeData(PyObject *obj, PyTypeObject *cls) {