bpo-38785: Prevent asyncio from crashing (GH-17144)
if parent `__init__` is not called from a constructor of object derived from `asyncio.Future`
https://bugs.python.org/issue38785
diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
index 98a5308e..9afda22 100644
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -115,7 +115,10 @@
def get_loop(self):
"""Return the event loop the Future is bound to."""
- return self._loop
+ loop = self._loop
+ if loop is None:
+ raise RuntimeError("Future object is not initialized.")
+ return loop
def cancel(self):
"""Cancel the future and schedule callbacks.
diff --git a/Lib/test/test_asyncio/test_futures.py b/Lib/test/test_asyncio/test_futures.py
index 2e4583d..ee5edd5 100644
--- a/Lib/test/test_asyncio/test_futures.py
+++ b/Lib/test/test_asyncio/test_futures.py
@@ -822,5 +822,44 @@
return futures._PyFuture(loop=self.loop)
+class BaseFutureInheritanceTests:
+
+ def _get_future_cls(self):
+ raise NotImplementedError
+
+ def setUp(self):
+ super().setUp()
+ self.loop = self.new_test_loop()
+ self.addCleanup(self.loop.close)
+
+ def test_inherit_without_calling_super_init(self):
+ # See https://bugs.python.org/issue38785 for the context
+ cls = self._get_future_cls()
+
+ class MyFut(cls):
+ def __init__(self, *args, **kwargs):
+ # don't call super().__init__()
+ pass
+
+ fut = MyFut(loop=self.loop)
+ with self.assertRaisesRegex(
+ RuntimeError,
+ "Future object is not initialized."
+ ):
+ fut.get_loop()
+
+
+class PyFutureInheritanceTests(BaseFutureInheritanceTests,
+ test_utils.TestCase):
+ def _get_future_cls(self):
+ return futures._PyFuture
+
+
+class CFutureInheritanceTests(BaseFutureInheritanceTests,
+ test_utils.TestCase):
+ def _get_future_cls(self):
+ return futures._CFuture
+
+
if __name__ == '__main__':
unittest.main()