text: import pytest
  from pybind11_tests import ConstructorStats
  from pybind11_tests import multiple_inheritance as m
  
  
  def test_multiple_inheritance_cpp():
      mt = m.MIType(3, 4)
  
      assert mt.foo() == 3
      assert mt.bar() == 4
  
  
  def test_multiple_inheritance_mix1():
      class Base1:
          def __init__(self, i):
              self.i = i
  
          def foo(self):
              return self.i
  
      class MITypePy(Base1, m.Base2):
          def __init__(self, i, j):
              Base1.__init__(self, i)
              m.Base2.__init__(self, j)
  
      mt = MITypePy(3, 4)
  
      assert mt.foo() == 3
      assert mt.bar() == 4
  
  
  def test_multiple_inheritance_mix2():
      class Base2:
          def __init__(self, i):
              self.i = i
  
          def bar(self):
              return self.i
  
      class MITypePy(m.Base1, Base2):
          def __init__(self, i, j):
              m.Base1.__init__(self, i)
              Base2.__init__(self, j)
  
      mt = MITypePy(3, 4)
  
      assert mt.foo() == 3
      assert mt.bar() == 4
  
  
  def test_multiple_inheritance_python():
      class MI1(m.Base1, m.Base2):
          def __init__(self, i, j):
              m.Base1.__init__(self, i)
              m.Base2.__init__(self, j)
  
      class B1(object):
          def v(self):
              return 1
  
      class MI2(B1, m.Base1, m.Base2):
          def __init__(self, i, j):
              B1.__init__(self)
              m.Base1.__init__(self, i)
              m.Base2.__init__(self, j)
  
      class MI3(MI2):
          def __init__(self, i, j):
              MI2.__init__(self, i, j)
  
      class MI4(MI3, m.Base2):
          def __init__(self, i, j):
              MI3.__init__(self, i, j)
              # This should be ignored (Base2 is already initialized via MI2):
              m.Base2.__init__(self, i + 100)
  
      class MI5(m.Base2, B1, m.Base1):
          def __init__(self, i, j):
              B1.__init__(self)
              m.Base1.__init__(self, i)
              m.Base2.__init__(self, j)
  
      class MI6(m.Base2, B1):
          def __init__(self, i):
              m.Base2.__init__(self, i)
              B1.__init__(self)
  
      class B2(B1):
          def v(self):
              return 2
  
      class B3(object):
          def v(self):
              return 3
  
      class B4(B3, B2):
          def v(self):
              return 4
  
      class MI7(B4, MI6):
          def __init__(self, i):
              B4.__init__(self)
              MI6.__init__(self, i)
  
      class MI8(MI6, B3):
          def __init__(self, i):
              MI6.__init__(self, i)
              B3.__init__(self)
  
      class MI8b(B3, MI6):
          def __init__(self, i):
              B3.__init__(self)
              MI6.__init__(self, i)
  
      mi1 = MI1(1, 2)
      assert mi1.foo() == 1
      assert mi1.bar() == 2
  
      mi2 = MI2(3, 4)
      assert mi2.v() == 1
      assert mi2.foo() == 3
      assert mi2.bar() == 4
  
      mi3 = MI3(5, 6)
      assert mi3.v() == 1
      assert mi3.foo() == 5
      assert mi3.bar() == 6
  
      mi4 = MI4(7, 8)
      assert mi4.v() == 1
      assert mi4.foo() == 7
      assert mi4.bar() == 8
  
      mi5 = MI5(10, 11)
      assert mi5.v() == 1
      assert mi5.foo() == 10
      assert mi5.bar() == 11
  
      mi6 = MI6(12)
      assert mi6.v() == 1
      assert mi6.bar() == 12
  
      mi7 = MI7(13)
      assert mi7.v() == 4
      assert mi7.bar() == 13
  
      mi8 = MI8(14)
      assert mi8.v() == 1
      assert mi8.bar() == 14
  
      mi8b = MI8b(15)
      assert mi8b.v() == 3
      assert mi8b.bar() == 15
  
  
  def test_multiple_inheritance_python_many_bases():
      class MIMany14(m.BaseN1, m.BaseN2, m.BaseN3, m.BaseN4):
          def __init__(self):
              m.BaseN1.__init__(self, 1)
              m.BaseN2.__init__(self, 2)
              m.BaseN3.__init__(self, 3)
              m.BaseN4.__init__(self, 4)
  
      class MIMany58(m.BaseN5, m.BaseN6, m.BaseN7, m.BaseN8):
          def __init__(self):
              m.BaseN5.__init__(self, 5)
              m.BaseN6.__init__(self, 6)
              m.BaseN7.__init__(self, 7)
              m.BaseN8.__init__(self, 8)
  
      class MIMany916(
          m.BaseN9,
          m.BaseN10,
          m.BaseN11,
          m.BaseN12,
          m.BaseN13,
          m.BaseN14,
          m.BaseN15,
          m.BaseN16,
      ):
          def __init__(self):
              m.BaseN9.__init__(self, 9)
              m.BaseN10.__init__(self, 10)
              m.BaseN11.__init__(self, 11)
              m.BaseN12.__init__(self, 12)
              m.BaseN13.__init__(self, 13)
              m.BaseN14.__init__(self, 14)
              m.BaseN15.__init__(self, 15)
              m.BaseN16.__init__(self, 16)
  
      class MIMany19(MIMany14, MIMany58, m.BaseN9):
          def __init__(self):
              MIMany14.__init__(self)
              MIMany58.__init__(self)
              m.BaseN9.__init__(self, 9)
  
      class MIMany117(MIMany14, MIMany58, MIMany916, m.BaseN17):
          def __init__(self):
              MIMany14.__init__(self)
              MIMany58.__init__(self)
              MIMany916.__init__(self)
              m.BaseN17.__init__(self, 17)
  
      # Inherits from 4 registered C++ classes: can fit in one pointer on any modern arch:
      a = MIMany14()
      for i in range(1, 4):
          assert getattr(a, "f" + str(i))() == 2 * i
  
      # Inherits from 8: requires 1/2 pointers worth of holder flags on 32/64-bit arch:
      b = MIMany916()
      for i in range(9, 16):
          assert getattr(b, "f" + str(i))() == 2 * i
  
      # Inherits from 9: requires >= 2 pointers worth of holder flags
      c = MIMany19()
      for i in range(1, 9):
          assert getattr(c, "f" + str(i))() == 2 * i
  
      # Inherits from 17: requires >= 3 pointers worth of holder flags
      d = MIMany117()
      for i in range(1, 17):
          assert getattr(d, "f" + str(i))() == 2 * i
  
  
  def test_multiple_inheritance_virtbase():
      class MITypePy(m.Base12a):
          def __init__(self, i, j):
              m.Base12a.__init__(self, i, j)
  
      mt = MITypePy(3, 4)
      assert mt.bar() == 4
      assert m.bar_base2a(mt) == 4
      assert m.bar_base2a_sharedptr(mt) == 4
  
  
  def test_mi_static_properties():
      """Mixing bases with and without static properties should be possible and
      the result should be independent of base definition order."""
  
      for d in (m.VanillaStaticMix1(), m.VanillaStaticMix2()):
          assert d.vanilla() == "Vanilla"
          assert d.static_func1() == "WithStatic1"
          assert d.static_func2() == "WithStatic2"
          assert d.static_func() == d.__class__.__name__
  
          m.WithStatic1.static_value1 = 1
          m.WithStatic2.static_value2 = 2
          assert d.static_value1 == 1
          assert d.static_value2 == 2
          assert d.static_value == 12
  
          d.static_value1 = 0
          assert d.static_value1 == 0
          d.static_value2 = 0
          assert d.static_value2 == 0
          d.static_value = 0
          assert d.static_value == 0
  
  
  @pytest.unsupported_on_pypy
  def test_mi_dynamic_attributes():
      """Mixing bases with and without dynamic attribute support."""
  
      for d in (m.VanillaDictMix1(), m.VanillaDictMix2()):
          d.dynamic = 1
          assert d.dynamic == 1
  
  
  def test_mi_unaligned_base():
      """Returning an offset (non-first MI) base class pointer should recognize
      the instance."""
  
      n_inst = ConstructorStats.detail_reg_inst()
  
      c = m.I801C()
      d = m.I801D()
      # + 4 below because we have the two instances, and each instance has offset base I801B2
      assert ConstructorStats.detail_reg_inst() == n_inst + 4
      b1c = m.i801b1_c(c)
      assert b1c is c
      b2c = m.i801b2_c(c)
      assert b2c is c
      b1d = m.i801b1_d(d)
      assert b1d is d
      b2d = m.i801b2_d(d)
      assert b2d is d
  
      assert ConstructorStats.detail_reg_inst() == n_inst + 4  # no extra instances
      del c, b1c, b2c
      assert ConstructorStats.detail_reg_inst() == n_inst + 2
      del d, b1d, b2d
      assert ConstructorStats.detail_reg_inst() == n_inst
  
  
  def test_mi_base_return():
      """Tests returning an offset (non-first MI) base class pointer to a derived
      instance."""
  
      n_inst = ConstructorStats.detail_reg_inst()
  
      c1 = m.i801c_b1()
      assert type(c1) is m.I801C
      assert c1.a == 1
      assert c1.b == 2
  
      d1 = m.i801d_b1()
      assert type(d1) is m.I801D
      assert d1.a == 1
      assert d1.b == 2
  
      assert ConstructorStats.detail_reg_inst() == n_inst + 4
  
      c2 = m.i801c_b2()
      assert type(c2) is m.I801C
      assert c2.a == 1
      assert c2.b == 2
  
      d2 = m.i801d_b2()
      assert type(d2) is m.I801D
      assert d2.a == 1
      assert d2.b == 2
  
      assert ConstructorStats.detail_reg_inst() == n_inst + 8
  
      del c2
      assert ConstructorStats.detail_reg_inst() == n_inst + 6
      del c1, d1, d2
      assert ConstructorStats.detail_reg_inst() == n_inst
  
      # Returning an unregistered derived type with a registered base; we won't
      # pick up the derived type, obviously, but should still work (as an object
      # of whatever type was returned).
      e1 = m.i801e_c()
      assert type(e1) is m.I801C
      assert e1.a == 1
      assert e1.b == 2
  
      e2 = m.i801e_b2()
      assert type(e2) is m.I801B2
      assert e2.b == 2
  
  
  def test_diamond_inheritance():
      """Tests that diamond inheritance works as expected (issue #959)"""
  
      # Issue #959: this shouldn't segfault:
      d = m.D()
  
      # Make sure all the various distinct pointers are all recognized as registered instances:
      assert d is d.c0()
      assert d is d.c1()
      assert d is d.b()
      assert d is d.c0().b()
      assert d is d.c1().b()
      assert d is d.c0().c1().b().c0().b()
  