diff --git a/Doc/whatsnew/3.6.rst b/Doc/whatsnew/3.6.rst index 50d2a6ae6e5..b735e9cb27b 100644 --- a/Doc/whatsnew/3.6.rst +++ b/Doc/whatsnew/3.6.rst @@ -112,6 +112,15 @@ indexers. For example: ``subscript[0:10:2] == slice(0, 10, 2)`` (Contributed by Joe Jevnik in :issue:`24379`.) +pickle +------ + +Objects that need calling ``__new__`` with keyword arguments, can now be pickled +using :ref:`pickle protocols ` older than protocol version 4. +Protocol version 4 already supports this case. (Contributed by Serhiy +Storchaka in :issue:`24164`.) + + rlcomplete ---------- diff --git a/Lib/pickle.py b/Lib/pickle.py index e93057a7f84..d41753d2d25 100644 --- a/Lib/pickle.py +++ b/Lib/pickle.py @@ -27,6 +27,7 @@ from types import FunctionType from copyreg import dispatch_table from copyreg import _extension_registry, _inverted_registry, _extension_cache from itertools import islice +from functools import partial import sys from sys import maxsize from struct import pack, unpack @@ -544,7 +545,7 @@ class _Pickler: write = self.write func_name = getattr(func, "__name__", "") - if self.proto >= 4 and func_name == "__newobj_ex__": + if self.proto >= 2 and func_name == "__newobj_ex__": cls, args, kwargs = args if not hasattr(cls, "__new__"): raise PicklingError("args[0] from {} args has no __new__" @@ -552,10 +553,16 @@ class _Pickler: if obj is not None and cls is not obj.__class__: raise PicklingError("args[0] from {} args has the wrong class" .format(func_name)) - save(cls) - save(args) - save(kwargs) - write(NEWOBJ_EX) + if self.proto >= 4: + save(cls) + save(args) + save(kwargs) + write(NEWOBJ_EX) + else: + func = partial(cls.__new__, cls, *args, **kwargs) + save(func) + save(()) + write(REDUCE) elif self.proto >= 2 and func_name == "__newobj__": # A __reduce__ implementation can direct protocol 2 or newer to # use the more efficient NEWOBJ opcode, while still diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py index 2ef48e64d74..fd641e31617 100644 --- a/Lib/test/pickletester.py +++ b/Lib/test/pickletester.py @@ -1580,16 +1580,14 @@ class AbstractPickleTests(unittest.TestCase): x.abc = 666 for proto in protocols: with self.subTest(proto=proto): - if 2 <= proto < 4: - self.assertRaises(ValueError, self.dumps, x, proto) - continue s = self.dumps(x, proto) if proto < 1: self.assertIn(b'\nL64206', s) # LONG elif proto < 2: self.assertIn(b'M\xce\xfa', s) # BININT2 + elif proto < 4: + self.assertIn(b'X\x04\x00\x00\x00FACE', s) # BINUNICODE else: - assert proto >= 4 self.assertIn(b'\x8c\x04FACE', s) # SHORT_BINUNICODE self.assertFalse(opcode_in_pickle(pickle.NEWOBJ, s)) self.assertEqual(opcode_in_pickle(pickle.NEWOBJ_EX, s), diff --git a/Misc/NEWS b/Misc/NEWS index cb02aae2c6a..802f4b6920a 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -51,6 +51,9 @@ Core and Builtins Library ------- +- Issue #24164: Objects that need calling ``__new__`` with keyword arguments, + can now be pickled using pickle protocols older than protocol version 4. + - Issue #25364: zipfile now works in threads disabled builds. - Issue #25328: smtpd's SMTPChannel now correctly raises a ValueError if both diff --git a/Modules/_pickle.c b/Modules/_pickle.c index f3b73f176dd..abaf4e52298 100644 --- a/Modules/_pickle.c +++ b/Modules/_pickle.c @@ -153,6 +153,9 @@ typedef struct { PyObject *codecs_encode; /* builtins.getattr, used for saving nested names with protocol < 4 */ PyObject *getattr; + /* functools.partial, used for implementing __newobj_ex__ with protocols + 2 and 3 */ + PyObject *partial; } PickleState; /* Forward declaration of the _pickle module definition. */ @@ -200,6 +203,7 @@ _Pickle_InitState(PickleState *st) PyObject *copyreg = NULL; PyObject *compat_pickle = NULL; PyObject *codecs = NULL; + PyObject *functools = NULL; builtins = PyEval_GetBuiltins(); if (builtins == NULL) @@ -314,12 +318,21 @@ _Pickle_InitState(PickleState *st) } Py_CLEAR(codecs); + functools = PyImport_ImportModule("functools"); + if (!functools) + goto error; + st->partial = PyObject_GetAttrString(functools, "partial"); + if (!st->partial) + goto error; + Py_CLEAR(functools); + return 0; error: Py_CLEAR(copyreg); Py_CLEAR(compat_pickle); Py_CLEAR(codecs); + Py_CLEAR(functools); _Pickle_ClearState(st); return -1; } @@ -3533,11 +3546,9 @@ save_reduce(PicklerObject *self, PyObject *args, PyObject *obj) PyErr_Clear(); } else if (PyUnicode_Check(name)) { - if (self->proto >= 4) { - _Py_IDENTIFIER(__newobj_ex__); - use_newobj_ex = PyUnicode_Compare( - name, _PyUnicode_FromId(&PyId___newobj_ex__)) == 0; - } + _Py_IDENTIFIER(__newobj_ex__); + use_newobj_ex = PyUnicode_Compare( + name, _PyUnicode_FromId(&PyId___newobj_ex__)) == 0; if (!use_newobj_ex) { _Py_IDENTIFIER(__newobj__); use_newobj = PyUnicode_Compare( @@ -3581,11 +3592,58 @@ save_reduce(PicklerObject *self, PyObject *args, PyObject *obj) return -1; } - if (save(self, cls, 0) < 0 || - save(self, args, 0) < 0 || - save(self, kwargs, 0) < 0 || - _Pickler_Write(self, &newobj_ex_op, 1) < 0) { - return -1; + if (self->proto >= 4) { + if (save(self, cls, 0) < 0 || + save(self, args, 0) < 0 || + save(self, kwargs, 0) < 0 || + _Pickler_Write(self, &newobj_ex_op, 1) < 0) { + return -1; + } + } + else { + PyObject *newargs; + PyObject *cls_new; + Py_ssize_t i; + _Py_IDENTIFIER(__new__); + + newargs = PyTuple_New(Py_SIZE(args) + 2); + if (newargs == NULL) + return -1; + + cls_new = _PyObject_GetAttrId(cls, &PyId___new__); + if (cls_new == NULL) { + Py_DECREF(newargs); + return -1; + } + PyTuple_SET_ITEM(newargs, 0, cls_new); + Py_INCREF(cls); + PyTuple_SET_ITEM(newargs, 1, cls); + for (i = 0; i < Py_SIZE(args); i++) { + PyObject *item = PyTuple_GET_ITEM(args, i); + Py_INCREF(item); + PyTuple_SET_ITEM(newargs, i + 2, item); + } + + callable = PyObject_Call(st->partial, newargs, kwargs); + Py_DECREF(newargs); + if (callable == NULL) + return -1; + + newargs = PyTuple_New(0); + if (newargs == NULL) { + Py_DECREF(callable); + return -1; + } + + if (save(self, callable, 0) < 0 || + save(self, newargs, 0) < 0 || + _Pickler_Write(self, &reduce_op, 1) < 0) { + Py_DECREF(newargs); + Py_DECREF(callable); + return -1; + } + Py_DECREF(newargs); + Py_DECREF(callable); } } else if (use_newobj) { diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 4b091f5dfdb..bf0d30cac30 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -4101,7 +4101,7 @@ _PyObject_GetItemsIter(PyObject *obj, PyObject **listitems, } static PyObject * -reduce_newobj(PyObject *obj, int proto) +reduce_newobj(PyObject *obj) { PyObject *args = NULL, *kwargs = NULL; PyObject *copyreg; @@ -4153,7 +4153,7 @@ reduce_newobj(PyObject *obj, int proto) } Py_DECREF(args); } - else if (proto >= 4) { + else { _Py_IDENTIFIER(__newobj_ex__); newobj = _PyObject_GetAttrId(copyreg, &PyId___newobj_ex__); @@ -4171,16 +4171,6 @@ reduce_newobj(PyObject *obj, int proto) return NULL; } } - else { - PyErr_SetString(PyExc_ValueError, - "must use protocol 4 or greater to copy this " - "object; since __getnewargs_ex__ returned " - "keyword arguments."); - Py_DECREF(args); - Py_DECREF(kwargs); - Py_DECREF(copyreg); - return NULL; - } state = _PyObject_GetState(obj); if (state == NULL) { @@ -4225,7 +4215,7 @@ _common_reduce(PyObject *self, int proto) PyObject *copyreg, *res; if (proto >= 2) - return reduce_newobj(self, proto); + return reduce_newobj(self); copyreg = import_copyreg(); if (!copyreg)