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Merged
ilevkivskyi merged 2 commits into from
Jan 27, 2018
Merged

Pass *args and **kwargs to superclass in Generic.__new__ #517

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f5b9c81
Pass *args and **kwargs to superclass in Generic.__new__
chadrik Dec 10, 2017
23674e6
Protect against an edge case with multiple parent classes with __init__
chadrik Dec 15, 2017
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67 changes: 67 additions & 0 deletions python2/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1229,6 +1229,73 @@ class D(C):
with self.assertRaises(Exception):
D[T]

def test_new_with_args(self):

class A(Generic[T]):
pass

class B(object):
def __new__(cls, arg):
# call object.__new__
obj = super(B, cls).__new__(cls)
obj.arg = arg
return obj

# mro: C, A, Generic, B, object
class C(A, B):
pass

c = C('foo')
self.assertEqual(c.arg, 'foo')

def test_new_with_args2(self):

class A(object):
def __init__(self, arg):
self.from_a = arg
# call object
super(A, self).__init__()

# mro: C, Generic, A, object
class C(Generic[T], A):
def __init__(self, arg):
self.from_c = arg
# call Generic
super(C, self).__init__(arg)

c = C('foo')
self.assertEqual(c.from_a, 'foo')
self.assertEqual(c.from_c, 'foo')

def test_new_no_args(self):

class A(Generic[T]):
pass

class B(object):
def __new__(cls):
# call object
obj = super(B, cls).__new__(cls)
obj.from_b = 'b'
return obj

# mro: C, A, Generic, B, object
class C(A, B):
def __init__(self, arg):
self.arg = arg

def __new__(cls, arg):
# call A
obj = super(C, cls).__new__(cls)
obj.from_c = 'c'
return obj

c = C('foo')
self.assertEqual(c.arg, 'foo')
self.assertEqual(c.from_b, 'b')
self.assertEqual(c.from_c, 'c')



class ClassVarTests(BaseTestCase):

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10 changes: 8 additions & 2 deletions python2/typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1287,10 +1287,16 @@ def _generic_new(base_cls, cls, *args, **kwds):
# Assure type is erased on instantiation,
# but attempt to store it in __orig_class__
if cls.__origin__ is None:
return base_cls.__new__(cls)
if base_cls.__new__ is object.__new__:
return base_cls.__new__(cls)
else:
return base_cls.__new__(cls, *args, **kwds)
else:
origin = cls._gorg
obj = base_cls.__new__(origin)
if base_cls.__new__ is object.__new__:
obj = base_cls.__new__(origin)
else:
obj = base_cls.__new__(origin, *args, **kwds)
try:
obj.__orig_class__ = cls
except AttributeError:
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66 changes: 66 additions & 0 deletions src/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1310,6 +1310,72 @@ class D(C):
with self.assertRaises(Exception):
D[T]

def test_new_with_args(self):

class A(Generic[T]):
pass

class B:
def __new__(cls, arg):
# call object
obj = super().__new__(cls)
obj.arg = arg
return obj

# mro: C, A, Generic, B, object
class C(A, B):
pass

c = C('foo')
self.assertEqual(c.arg, 'foo')

def test_new_with_args2(self):

class A:
def __init__(self, arg):
self.from_a = arg
# call object
super().__init__()

# mro: C, Generic, A, object
class C(Generic[T], A):
def __init__(self, arg):
self.from_c = arg
# call Generic
super().__init__(arg)

c = C('foo')
self.assertEqual(c.from_a, 'foo')
self.assertEqual(c.from_c, 'foo')

def test_new_no_args(self):

class A(Generic[T]):
pass

class B:
def __new__(cls):
# call object
obj = super().__new__(cls)
obj.from_b = 'b'
return obj

# mro: C, A, Generic, B, object
class C(A, B):
def __init__(self, arg):
self.arg = arg

def __new__(cls, arg):
# call A
obj = super().__new__(cls)
obj.from_c = 'c'
return obj

c = C('foo')
self.assertEqual(c.arg, 'foo')
self.assertEqual(c.from_b, 'b')
self.assertEqual(c.from_c, 'c')


class ClassVarTests(BaseTestCase):

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10 changes: 8 additions & 2 deletions src/typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1181,10 +1181,16 @@ def _generic_new(base_cls, cls, *args, **kwds):
# Assure type is erased on instantiation,
# but attempt to store it in __orig_class__
if cls.__origin__ is None:
return base_cls.__new__(cls)
if base_cls.__new__ is object.__new__:
return base_cls.__new__(cls)
else:
return base_cls.__new__(cls, *args, **kwds)
else:
origin = cls._gorg
obj = base_cls.__new__(origin)
if base_cls.__new__ is object.__new__:
obj = base_cls.__new__(origin)
else:
obj = base_cls.__new__(origin, *args, **kwds)
try:
obj.__orig_class__ = cls
except AttributeError:
Expand Down