pybind11/tests/test_factory_constructors.py

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# -*- coding: utf-8 -*-
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
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import pytest
import re
import env # noqa: F401
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
2017-06-13 01:52:48 +00:00
from pybind11_tests import factory_constructors as m
from pybind11_tests.factory_constructors import tag
from pybind11_tests import ConstructorStats
def test_init_factory_basic():
"""Tests py::init_factory() wrapper around various ways of returning the object"""
cstats = [ConstructorStats.get(c) for c in [m.TestFactory1, m.TestFactory2, m.TestFactory3]]
cstats[0].alive() # force gc
n_inst = ConstructorStats.detail_reg_inst()
x1 = m.TestFactory1(tag.unique_ptr, 3)
assert x1.value == "3"
y1 = m.TestFactory1(tag.pointer)
assert y1.value == "(empty)"
z1 = m.TestFactory1("hi!")
assert z1.value == "hi!"
assert ConstructorStats.detail_reg_inst() == n_inst + 3
x2 = m.TestFactory2(tag.move)
assert x2.value == "(empty2)"
y2 = m.TestFactory2(tag.pointer, 7)
assert y2.value == "7"
z2 = m.TestFactory2(tag.unique_ptr, "hi again")
assert z2.value == "hi again"
assert ConstructorStats.detail_reg_inst() == n_inst + 6
x3 = m.TestFactory3(tag.shared_ptr)
assert x3.value == "(empty3)"
y3 = m.TestFactory3(tag.pointer, 42)
assert y3.value == "42"
z3 = m.TestFactory3("bye")
assert z3.value == "bye"
with pytest.raises(TypeError) as excinfo:
m.TestFactory3(tag.null_ptr)
assert str(excinfo.value) == "pybind11::init(): factory function returned nullptr"
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
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assert [i.alive() for i in cstats] == [3, 3, 3]
assert ConstructorStats.detail_reg_inst() == n_inst + 9
del x1, y2, y3, z3
assert [i.alive() for i in cstats] == [2, 2, 1]
assert ConstructorStats.detail_reg_inst() == n_inst + 5
del x2, x3, y1, z1, z2
assert [i.alive() for i in cstats] == [0, 0, 0]
assert ConstructorStats.detail_reg_inst() == n_inst
assert [i.values() for i in cstats] == [
["3", "hi!"],
["7", "hi again"],
["42", "bye"]
]
assert [i.default_constructions for i in cstats] == [1, 1, 1]
def test_init_factory_signature(msg):
with pytest.raises(TypeError) as excinfo:
m.TestFactory1("invalid", "constructor", "arguments")
assert msg(excinfo.value) == """
__init__(): incompatible constructor arguments. The following argument types are supported:
1. m.factory_constructors.TestFactory1(arg0: m.factory_constructors.tag.unique_ptr_tag, arg1: int)
2. m.factory_constructors.TestFactory1(arg0: str)
3. m.factory_constructors.TestFactory1(arg0: m.factory_constructors.tag.pointer_tag)
4. m.factory_constructors.TestFactory1(arg0: handle, arg1: int, arg2: handle)
Invoked with: 'invalid', 'constructor', 'arguments'
""" # noqa: E501 line too long
assert msg(m.TestFactory1.__init__.__doc__) == """
__init__(*args, **kwargs)
Overloaded function.
1. __init__(self: m.factory_constructors.TestFactory1, arg0: m.factory_constructors.tag.unique_ptr_tag, arg1: int) -> None
2. __init__(self: m.factory_constructors.TestFactory1, arg0: str) -> None
3. __init__(self: m.factory_constructors.TestFactory1, arg0: m.factory_constructors.tag.pointer_tag) -> None
4. __init__(self: m.factory_constructors.TestFactory1, arg0: handle, arg1: int, arg2: handle) -> None
""" # noqa: E501 line too long
def test_init_factory_casting():
"""Tests py::init_factory() wrapper with various upcasting and downcasting returns"""
cstats = [ConstructorStats.get(c) for c in [m.TestFactory3, m.TestFactory4, m.TestFactory5]]
cstats[0].alive() # force gc
n_inst = ConstructorStats.detail_reg_inst()
# Construction from derived references:
a = m.TestFactory3(tag.pointer, tag.TF4, 4)
assert a.value == "4"
b = m.TestFactory3(tag.shared_ptr, tag.TF4, 5)
assert b.value == "5"
c = m.TestFactory3(tag.pointer, tag.TF5, 6)
assert c.value == "6"
d = m.TestFactory3(tag.shared_ptr, tag.TF5, 7)
assert d.value == "7"
assert ConstructorStats.detail_reg_inst() == n_inst + 4
# Shared a lambda with TF3:
e = m.TestFactory4(tag.pointer, tag.TF4, 8)
assert e.value == "8"
assert ConstructorStats.detail_reg_inst() == n_inst + 5
assert [i.alive() for i in cstats] == [5, 3, 2]
del a
assert [i.alive() for i in cstats] == [4, 2, 2]
assert ConstructorStats.detail_reg_inst() == n_inst + 4
del b, c, e
assert [i.alive() for i in cstats] == [1, 0, 1]
assert ConstructorStats.detail_reg_inst() == n_inst + 1
del d
assert [i.alive() for i in cstats] == [0, 0, 0]
assert ConstructorStats.detail_reg_inst() == n_inst
assert [i.values() for i in cstats] == [
["4", "5", "6", "7", "8"],
["4", "5", "8"],
["6", "7"]
]
def test_init_factory_alias():
"""Tests py::init_factory() wrapper with value conversions and alias types"""
cstats = [m.TestFactory6.get_cstats(), m.TestFactory6.get_alias_cstats()]
cstats[0].alive() # force gc
n_inst = ConstructorStats.detail_reg_inst()
a = m.TestFactory6(tag.base, 1)
assert a.get() == 1
assert not a.has_alias()
b = m.TestFactory6(tag.alias, "hi there")
assert b.get() == 8
assert b.has_alias()
c = m.TestFactory6(tag.alias, 3)
assert c.get() == 3
assert c.has_alias()
d = m.TestFactory6(tag.alias, tag.pointer, 4)
assert d.get() == 4
assert d.has_alias()
e = m.TestFactory6(tag.base, tag.pointer, 5)
assert e.get() == 5
assert not e.has_alias()
f = m.TestFactory6(tag.base, tag.alias, tag.pointer, 6)
assert f.get() == 6
assert f.has_alias()
assert ConstructorStats.detail_reg_inst() == n_inst + 6
assert [i.alive() for i in cstats] == [6, 4]
del a, b, e
assert [i.alive() for i in cstats] == [3, 3]
assert ConstructorStats.detail_reg_inst() == n_inst + 3
del f, c, d
assert [i.alive() for i in cstats] == [0, 0]
assert ConstructorStats.detail_reg_inst() == n_inst
class MyTest(m.TestFactory6):
def __init__(self, *args):
m.TestFactory6.__init__(self, *args)
def get(self):
return -5 + m.TestFactory6.get(self)
# Return Class by value, moved into new alias:
z = MyTest(tag.base, 123)
assert z.get() == 118
assert z.has_alias()
# Return alias by value, moved into new alias:
y = MyTest(tag.alias, "why hello!")
assert y.get() == 5
assert y.has_alias()
# Return Class by pointer, moved into new alias then original destroyed:
x = MyTest(tag.base, tag.pointer, 47)
assert x.get() == 42
assert x.has_alias()
assert ConstructorStats.detail_reg_inst() == n_inst + 3
assert [i.alive() for i in cstats] == [3, 3]
del x, y, z
assert [i.alive() for i in cstats] == [0, 0]
assert ConstructorStats.detail_reg_inst() == n_inst
assert [i.values() for i in cstats] == [
["1", "8", "3", "4", "5", "6", "123", "10", "47"],
["hi there", "3", "4", "6", "move", "123", "why hello!", "move", "47"]
]
def test_init_factory_dual():
"""Tests init factory functions with dual main/alias factory functions"""
from pybind11_tests.factory_constructors import TestFactory7
cstats = [TestFactory7.get_cstats(), TestFactory7.get_alias_cstats()]
cstats[0].alive() # force gc
n_inst = ConstructorStats.detail_reg_inst()
class PythFactory7(TestFactory7):
def get(self):
return 100 + TestFactory7.get(self)
a1 = TestFactory7(1)
a2 = PythFactory7(2)
assert a1.get() == 1
assert a2.get() == 102
assert not a1.has_alias()
assert a2.has_alias()
b1 = TestFactory7(tag.pointer, 3)
b2 = PythFactory7(tag.pointer, 4)
assert b1.get() == 3
assert b2.get() == 104
assert not b1.has_alias()
assert b2.has_alias()
c1 = TestFactory7(tag.mixed, 5)
c2 = PythFactory7(tag.mixed, 6)
assert c1.get() == 5
assert c2.get() == 106
assert not c1.has_alias()
assert c2.has_alias()
d1 = TestFactory7(tag.base, tag.pointer, 7)
d2 = PythFactory7(tag.base, tag.pointer, 8)
assert d1.get() == 7
assert d2.get() == 108
assert not d1.has_alias()
assert d2.has_alias()
# Both return an alias; the second multiplies the value by 10:
e1 = TestFactory7(tag.alias, tag.pointer, 9)
e2 = PythFactory7(tag.alias, tag.pointer, 10)
assert e1.get() == 9
assert e2.get() == 200
assert e1.has_alias()
assert e2.has_alias()
f1 = TestFactory7(tag.shared_ptr, tag.base, 11)
f2 = PythFactory7(tag.shared_ptr, tag.base, 12)
assert f1.get() == 11
assert f2.get() == 112
assert not f1.has_alias()
assert f2.has_alias()
g1 = TestFactory7(tag.shared_ptr, tag.invalid_base, 13)
assert g1.get() == 13
assert not g1.has_alias()
with pytest.raises(TypeError) as excinfo:
PythFactory7(tag.shared_ptr, tag.invalid_base, 14)
assert (str(excinfo.value) ==
"pybind11::init(): construction failed: returned holder-wrapped instance is not an "
"alias instance")
assert [i.alive() for i in cstats] == [13, 7]
assert ConstructorStats.detail_reg_inst() == n_inst + 13
del a1, a2, b1, d1, e1, e2
assert [i.alive() for i in cstats] == [7, 4]
assert ConstructorStats.detail_reg_inst() == n_inst + 7
del b2, c1, c2, d2, f1, f2, g1
assert [i.alive() for i in cstats] == [0, 0]
assert ConstructorStats.detail_reg_inst() == n_inst
assert [i.values() for i in cstats] == [
["1", "2", "3", "4", "5", "6", "7", "8", "9", "100", "11", "12", "13", "14"],
["2", "4", "6", "8", "9", "100", "12"]
]
def test_no_placement_new(capture):
"""Prior to 2.2, `py::init<...>` relied on the type supporting placement
new; this tests a class without placement new support."""
with capture:
a = m.NoPlacementNew(123)
found = re.search(r'^operator new called, returning (\d+)\n$', str(capture))
assert found
assert a.i == 123
with capture:
del a
pytest.gc_collect()
assert capture == "operator delete called on " + found.group(1)
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
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with capture:
b = m.NoPlacementNew()
found = re.search(r'^operator new called, returning (\d+)\n$', str(capture))
assert found
assert b.i == 100
with capture:
del b
pytest.gc_collect()
assert capture == "operator delete called on " + found.group(1)
def test_multiple_inheritance():
class MITest(m.TestFactory1, m.TestFactory2):
def __init__(self):
m.TestFactory1.__init__(self, tag.unique_ptr, 33)
m.TestFactory2.__init__(self, tag.move)
a = MITest()
assert m.TestFactory1.value.fget(a) == "33"
assert m.TestFactory2.value.fget(a) == "(empty2)"
def create_and_destroy(*args):
a = m.NoisyAlloc(*args)
print("---")
del a
pytest.gc_collect()
def strip_comments(s):
return re.sub(r'\s+#.*', '', s)
def test_reallocations(capture, msg):
"""When the constructor is overloaded, previous overloads can require a preallocated value.
This test makes sure that such preallocated values only happen when they might be necessary,
and that they are deallocated properly"""
pytest.gc_collect()
with capture:
create_and_destroy(1)
assert msg(capture) == """
noisy new
noisy placement new
NoisyAlloc(int 1)
---
~NoisyAlloc()
noisy delete
"""
with capture:
create_and_destroy(1.5)
assert msg(capture) == strip_comments("""
noisy new # allocation required to attempt first overload
noisy delete # have to dealloc before considering factory init overload
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
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noisy new # pointer factory calling "new", part 1: allocation
NoisyAlloc(double 1.5) # ... part two, invoking constructor
---
~NoisyAlloc() # Destructor
noisy delete # operator delete
""")
with capture:
create_and_destroy(2, 3)
assert msg(capture) == strip_comments("""
noisy new # pointer factory calling "new", allocation
NoisyAlloc(int 2) # constructor
---
~NoisyAlloc() # Destructor
noisy delete # operator delete
""")
with capture:
create_and_destroy(2.5, 3)
assert msg(capture) == strip_comments("""
NoisyAlloc(double 2.5) # construction (local func variable: operator_new not called)
noisy new # return-by-value "new" part 1: allocation
~NoisyAlloc() # moved-away local func variable destruction
---
~NoisyAlloc() # Destructor
noisy delete # operator delete
""")
with capture:
create_and_destroy(3.5, 4.5)
assert msg(capture) == strip_comments("""
noisy new # preallocation needed before invoking placement-new overload
noisy placement new # Placement new
NoisyAlloc(double 3.5) # construction
---
~NoisyAlloc() # Destructor
noisy delete # operator delete
""")
with capture:
create_and_destroy(4, 0.5)
assert msg(capture) == strip_comments("""
noisy new # preallocation needed before invoking placement-new overload
noisy delete # deallocation of preallocated storage
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
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noisy new # Factory pointer allocation
NoisyAlloc(int 4) # factory pointer construction
---
~NoisyAlloc() # Destructor
noisy delete # operator delete
""")
with capture:
create_and_destroy(5, "hi")
assert msg(capture) == strip_comments("""
noisy new # preallocation needed before invoking first placement new
noisy delete # delete before considering new-style constructor
noisy new # preallocation for second placement new
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
2017-06-13 01:52:48 +00:00
noisy placement new # Placement new in the second placement new overload
NoisyAlloc(int 5) # construction
---
~NoisyAlloc() # Destructor
noisy delete # operator delete
""")
@pytest.mark.skipif("env.PY2")
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
2017-06-13 01:52:48 +00:00
def test_invalid_self():
"""Tests invocation of the pybind-registered base class with an invalid `self` argument. You
can only actually do this on Python 3: Python 2 raises an exception itself if you try."""
class NotPybindDerived(object):
pass
# Attempts to initialize with an invalid type passed as `self`:
class BrokenTF1(m.TestFactory1):
def __init__(self, bad):
if bad == 1:
a = m.TestFactory2(tag.pointer, 1)
m.TestFactory1.__init__(a, tag.pointer)
elif bad == 2:
a = NotPybindDerived()
m.TestFactory1.__init__(a, tag.pointer)
# Same as above, but for a class with an alias:
class BrokenTF6(m.TestFactory6):
def __init__(self, bad):
if bad == 1:
a = m.TestFactory2(tag.pointer, 1)
m.TestFactory6.__init__(a, tag.base, 1)
elif bad == 2:
a = m.TestFactory2(tag.pointer, 1)
m.TestFactory6.__init__(a, tag.alias, 1)
elif bad == 3:
m.TestFactory6.__init__(NotPybindDerived.__new__(NotPybindDerived), tag.base, 1)
elif bad == 4:
m.TestFactory6.__init__(NotPybindDerived.__new__(NotPybindDerived), tag.alias, 1)
for arg in (1, 2):
with pytest.raises(TypeError) as excinfo:
BrokenTF1(arg)
assert str(excinfo.value) == "__init__(self, ...) called with invalid `self` argument"
Allow binding factory functions as constructors This allows you to use: cls.def(py::init(&factory_function)); where `factory_function` returns a pointer, holder, or value of the class type (or a derived type). Various compile-time checks (static_asserts) are performed to ensure the function is valid, and various run-time type checks where necessary. Some other details of this feature: - The `py::init` name doesn't conflict with the templated no-argument `py::init<...>()`, but keeps the naming consistent: the existing templated, no-argument one wraps constructors, the no-template, function-argument one wraps factory functions. - If returning a CppClass (whether by value or pointer) when an CppAlias is required (i.e. python-side inheritance and a declared alias), a dynamic_cast to the alias is attempted (for the pointer version); if it fails, or if returned by value, an Alias(Class &&) constructor is invoked. If this constructor doesn't exist, a runtime error occurs. - for holder returns when an alias is required, we try a dynamic_cast of the wrapped pointer to the alias to see if it is already an alias instance; if it isn't, we raise an error. - `py::init(class_factory, alias_factory)` is also available that takes two factories: the first is called when an alias is not needed, the second when it is. - Reimplement factory instance clearing. The previous implementation failed under python-side multiple inheritance: *each* inherited type's factory init would clear the instance instead of only setting its own type value. The new implementation here clears just the relevant value pointer. - dealloc is updated to explicitly set the leftover value pointer to nullptr and the `holder_constructed` flag to false so that it can be used to clear preallocated value without needing to rebuild the instance internals data. - Added various tests to test out new allocation/deallocation code. - With preallocation now done lazily, init factory holders can completely avoid the extra overhead of needing an extra allocation/deallocation. - Updated documentation to make factory constructors the default advanced constructor style. - If an `__init__` is called a second time, we have two choices: we can throw away the first instance, replacing it with the second; or we can ignore the second call. The latter is slightly easier, so do that.
2017-06-13 01:52:48 +00:00
for arg in (1, 2, 3, 4):
with pytest.raises(TypeError) as excinfo:
BrokenTF6(arg)
assert str(excinfo.value) == "__init__(self, ...) called with invalid `self` argument"