test_pickling.py

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from __future__ import annotations
 
import pickle
import re
 
import pytest
 
import env
from pybind11_tests import pickling as m
 
 
def test_pickle_simple_callable():
    assert m.simple_callable() == 20220426
    if env.PYPY:
        serialized = pickle.dumps(m.simple_callable)
        deserialized = pickle.loads(serialized)
        assert deserialized() == 20220426
    else:
        # To document broken behavior: currently it fails universally with
        # all C Python versions.
        with pytest.raises(TypeError) as excinfo:
            pickle.dumps(m.simple_callable)
        assert re.search("can.*t pickle .*PyCapsule.* object", str(excinfo.value))
 
 
@pytest.mark.parametrize("cls_name", ["Pickleable", "PickleableNew"])
def test_roundtrip(cls_name):
    cls = getattr(m, cls_name)
    p = cls("test_value")
    p.setExtra1(15)
    p.setExtra2(48)
 
    data = pickle.dumps(p, 2)  # Must use pickle protocol >= 2
    p2 = pickle.loads(data)
    assert p2.value() == p.value()
    assert p2.extra1() == p.extra1()
    assert p2.extra2() == p.extra2()
 
 
@pytest.mark.xfail("env.PYPY")
@pytest.mark.parametrize("cls_name", ["PickleableWithDict", "PickleableWithDictNew"])
def test_roundtrip_with_dict(cls_name):
    cls = getattr(m, cls_name)
    p = cls("test_value")
    p.extra = 15
    p.dynamic = "Attribute"
 
    data = pickle.dumps(p, pickle.HIGHEST_PROTOCOL)
    p2 = pickle.loads(data)
    assert p2.value == p.value
    assert p2.extra == p.extra
    assert p2.dynamic == p.dynamic
 
 
def test_enum_pickle():
    from pybind11_tests import enums as e
 
    data = pickle.dumps(e.EOne, 2)
    assert e.EOne == pickle.loads(data)
 
 
#
# exercise_trampoline
#
class SimplePyDerived(m.SimpleBase):
    pass
 
 
def test_roundtrip_simple_py_derived():
    p = SimplePyDerived()
    p.num = 202
    p.stored_in_dict = 303
    data = pickle.dumps(p, pickle.HIGHEST_PROTOCOL)
    p2 = pickle.loads(data)
    assert isinstance(p2, SimplePyDerived)
    assert p2.num == 202
    assert p2.stored_in_dict == 303
 
 
def test_roundtrip_simple_cpp_derived():
    p = m.make_SimpleCppDerivedAsBase()
    assert m.check_dynamic_cast_SimpleCppDerived(p)
    p.num = 404
    if not env.PYPY:
        # To ensure that this unit test is not accidentally invalidated.
        with pytest.raises(AttributeError):
            # Mimics the `setstate` C++ implementation.
            setattr(p, "__dict__", {})  # noqa: B010
    data = pickle.dumps(p, pickle.HIGHEST_PROTOCOL)
    p2 = pickle.loads(data)
    assert isinstance(p2, m.SimpleBase)
    assert p2.num == 404
    # Issue #3062: pickleable base C++ classes can incur object slicing
    #              if derived typeid is not registered with pybind11
    assert not m.check_dynamic_cast_SimpleCppDerived(p2)