def test_alias_delay_initialization1(capture):
"""A only initializes its trampoline class when we inherit from it; if we just
create and use an A instance directly, the trampoline initialization is bypassed
and we only initialize an A() instead (for performance reasons).
"""
from pybind11_tests import A, call_f
class B(A):
def __init__(self):
super(B, self).__init__()
def f(self):
print("In python f()")
# C++ version
with capture:
a = A()
call_f(a)
del a
gc.collect()
assert capture == "A.f()"
# Python version
with capture:
b = B()
call_f(b)
del b
gc.collect()
assert capture == """
def test_alias_delay_initialization2(capture):
"""A2, unlike the above, is configured to always initialize the alias; while
the extra initialization and extra class layer has small virtual dispatch
performance penalty, it also allows us to do more things with the trampoline
class such as defining local variables and performing construction/destruction.
"""
from pybind11_tests import A2, call_f
class B2(A2):
def __init__(self):
super(B2, self).__init__()
def f(self):
print("In python B2.f()")
# No python subclass version
with capture:
a2 = A2()
call_f(a2)
del a2
gc.collect()
assert capture == """
PyA2.PyA2()
PyA2.f()
A2.f()
PyA2.~PyA2()
"""
# Python subclass version
with capture:
b2 = B2()
call_f(b2)
del b2
gc.collect()
assert capture == """
def test_alias_delay_initialization1(capture):
"""
A only initializes its trampoline class when we inherit from it; if we just
create and use an A instance directly, the trampoline initialization is
bypassed and we only initialize an A() instead (for performance reasons).
"""
from pybind11_tests import A, call_f
class B(A):
def __init__(self):
super(B, self).__init__()
@staticmethod
def f():
print("In python f()")
# C++ version
with capture:
a = A()
call_f(a)
del a
pytest.gc_collect()
if capture != "A.f()":
raise AssertionError
# Python version
with capture:
b = B()
call_f(b)
del b
pytest.gc_collect()
if capture != """
PyA.PyA()
PyA.f()
In python f()
PyA.~PyA()
""":
raise AssertionError