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In order to fully satisfy Python's inheritance type layout requirements, all types should have a common 'solid' base. A solid base is one which has the same instance size as the derived type (not counting the space required for the optional `dict_ptr` and `weakrefs_ptr`). Thus, `object` does not qualify as a solid base for pybind11 types and this can lead to issues with multiple inheritance. To get around this, new base types are created: one per unique instance size. There is going to be very few of these bases. They ensure Python's MRO checks will pass when multiple bases are involved.
112 lines
2.8 KiB
Python
112 lines
2.8 KiB
Python
import pytest
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def test_multiple_inheritance_cpp():
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from pybind11_tests import MIType
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mt = MIType(3, 4)
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assert mt.foo() == 3
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assert mt.bar() == 4
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def test_multiple_inheritance_mix1():
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from pybind11_tests import Base2
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class Base1:
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def __init__(self, i):
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self.i = i
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def foo(self):
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return self.i
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class MITypePy(Base1, Base2):
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def __init__(self, i, j):
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Base1.__init__(self, i)
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Base2.__init__(self, j)
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mt = MITypePy(3, 4)
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assert mt.foo() == 3
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assert mt.bar() == 4
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def test_multiple_inheritance_mix2():
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from pybind11_tests import Base1
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class Base2:
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def __init__(self, i):
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self.i = i
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def bar(self):
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return self.i
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class MITypePy(Base1, Base2):
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def __init__(self, i, j):
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Base1.__init__(self, i)
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Base2.__init__(self, j)
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mt = MITypePy(3, 4)
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assert mt.foo() == 3
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assert mt.bar() == 4
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def test_multiple_inheritance_error():
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"""Inheriting from multiple C++ bases in Python is not supported"""
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from pybind11_tests import Base1, Base2
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with pytest.raises(TypeError) as excinfo:
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# noinspection PyUnusedLocal
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class MI(Base1, Base2):
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pass
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assert "Can't inherit from multiple C++ classes in Python" in str(excinfo.value)
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def test_multiple_inheritance_virtbase():
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from pybind11_tests import Base12a, bar_base2a, bar_base2a_sharedptr
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class MITypePy(Base12a):
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def __init__(self, i, j):
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Base12a.__init__(self, i, j)
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mt = MITypePy(3, 4)
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assert mt.bar() == 4
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assert bar_base2a(mt) == 4
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assert bar_base2a_sharedptr(mt) == 4
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def test_mi_static_properties():
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"""Mixing bases with and without static properties should be possible
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and the result should be independent of base definition order"""
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from pybind11_tests import mi
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for d in (mi.VanillaStaticMix1(), mi.VanillaStaticMix2()):
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assert d.vanilla() == "Vanilla"
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assert d.static_func1() == "WithStatic1"
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assert d.static_func2() == "WithStatic2"
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assert d.static_func() == d.__class__.__name__
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mi.WithStatic1.static_value1 = 1
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mi.WithStatic2.static_value2 = 2
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assert d.static_value1 == 1
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assert d.static_value2 == 2
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assert d.static_value == 12
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d.static_value1 = 0
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assert d.static_value1 == 0
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d.static_value2 = 0
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assert d.static_value2 == 0
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d.static_value = 0
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assert d.static_value == 0
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@pytest.unsupported_on_pypy
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def test_mi_dynamic_attributes():
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"""Mixing bases with and without dynamic attribute support"""
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from pybind11_tests import mi
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for d in (mi.VanillaDictMix1(), mi.VanillaDictMix2()):
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d.dynamic = 1
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assert d.dynamic == 1
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