[3.6] bpo-29822: make inspect.isabstract() work during __init_subclass__ (#1979)
At the time when an abstract base class' __init_subclass__ runs,
ABCMeta.__new__ has not yet finished running, so in the presence of
__init_subclass__, inspect.isabstract() can no longer depend only on
TPFLAGS_IS_ABSTRACT.
(cherry picked from commit fcfe80ec2592fed8b3941c79056a8737abef7d3b)
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index cfea281..37e4511 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -232,6 +232,30 @@
self.assertFalse(inspect.isabstract(int))
self.assertFalse(inspect.isabstract(5))
+ def test_isabstract_during_init_subclass(self):
+ from abc import ABCMeta, abstractmethod
+ isabstract_checks = []
+ class AbstractChecker(metaclass=ABCMeta):
+ def __init_subclass__(cls):
+ isabstract_checks.append(inspect.isabstract(cls))
+ class AbstractClassExample(AbstractChecker):
+ @abstractmethod
+ def foo(self):
+ pass
+ class ClassExample(AbstractClassExample):
+ def foo(self):
+ pass
+ self.assertEqual(isabstract_checks, [True, False])
+
+ isabstract_checks.clear()
+ class AbstractChild(AbstractClassExample):
+ pass
+ class AbstractGrandchild(AbstractChild):
+ pass
+ class ConcreteGrandchild(ClassExample):
+ pass
+ self.assertEqual(isabstract_checks, [True, True, False])
+
class TestInterpreterStack(IsTestBase):
def __init__(self, *args, **kwargs):