python
diff --git a/‎Lib/test/test_generators.py‎
Lines changed: 26 additions & 0 deletions b/‎Lib/test/test_generators.py‎
Lines changed: 26 additions & 0 deletions
diff --git a/‎Misc/ACKS‎
Lines changed: 1 addition & 0 deletions b/‎Misc/ACKS‎
Lines changed: 1 addition & 0 deletions
diff --git a/‎Misc/NEWS.d/next/Core and Builtins/2019-12-21-14-18-32.bpo-39091.dOexgQ.rst‎
Lines changed: 1 addition & 0 deletions b/‎Misc/NEWS.d/next/Core and Builtins/2019-12-21-14-18-32.bpo-39091.dOexgQ.rst‎
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diff --git a/‎Python/errors.c‎
Lines changed: 16 additions & 4 deletions b/‎Python/errors.c‎
Lines changed: 16 additions & 4 deletions
@@ -270,6 +270,32 @@ def gen():
         self.assertEqual(next(g), "done")
         self.assertEqual(sys.exc_info(), (None, None, None))
 
+    def test_except_throw_bad_exception(self):
+        class E(Exception):
+            def __new__(cls, *args, **kwargs):
+                return cls
+
+        def boring_generator():
+            yield
+
+        gen = boring_generator()
+
+        err_msg = 'should have returned an instance of BaseException'
+
+        with self.assertRaisesRegex(TypeError, err_msg):
+            gen.throw(E)
+
+        self.assertRaises(StopIteration, next, gen)
+
+        def generator():
+            with self.assertRaisesRegex(TypeError, err_msg):
+                yield
+
+        gen = generator()
+        next(gen)
+        with self.assertRaises(StopIteration):
+            gen.throw(E)
+
     def test_stopiteration_error(self):
         # See also PEP 479.
 
 
@@ -1300,6 +1300,7 @@ Peter Otten
 Michael Otteneder
 Richard Oudkerk
 Russel Owen
+Noah Oxer
 Joonas Paalasmaa
 Yaroslav Pankovych
 Martin Packman
 
@@ -0,0 +1 @@
+Fix crash when using passing a non-exception to a generator's ``throw()`` method. Patch by Noah Oxer
@@ -85,17 +85,29 @@ _PyErr_GetTopmostException(PyThreadState *tstate)
 }
 
 static PyObject*
-_PyErr_CreateException(PyObject *exception, PyObject *value)
+_PyErr_CreateException(PyObject *exception_type, PyObject *value)
 {
+    PyObject *exc;
+
     if (value == NULL || value == Py_None) {
-        return _PyObject_CallNoArg(exception);
+        exc = _PyObject_CallNoArg(exception_type);
     }
     else if (PyTuple_Check(value)) {
-        return PyObject_Call(exception, value, NULL);
+        exc = PyObject_Call(exception_type, value, NULL);
     }
     else {
-        return PyObject_CallOneArg(exception, value);
+        exc = PyObject_CallOneArg(exception_type, value);
+    }
+
+    if (exc != NULL && !PyExceptionInstance_Check(exc)) {
+        PyErr_Format(PyExc_TypeError,
+                     "calling %R should have returned an instance of "
+                     "BaseException, not %s",
+                     exception_type, Py_TYPE(exc)->tp_name);
+        Py_CLEAR(exc);
     }
+
+    return exc;
 }
 
 void
Original file line number	Diff line number	Diff line change
@@ -0,0 +1 @@
	1	+ Fix crash when using passing a non-exception to a generator's ``throw()`` method. Patch by Noah Oxer
Original file line number	Diff line number	Diff line change
@@ -85,17 +85,29 @@ _PyErr_GetTopmostException(PyThreadState *tstate)
85	85	}
86	86
87	87	static PyObject*
88		- _PyErr_CreateException(PyObject exception, PyObject value)
	88	+ _PyErr_CreateException(PyObject exception_type, PyObject value)
89	89	{
	90	+ PyObject *exc;
	91	+
90	92	if (value == NULL \|\| value == Py_None) {
91		- return _PyObject_CallNoArg(exception);
	93	+ exc = _PyObject_CallNoArg(exception_type);
92	94	}
93	95	else if (PyTuple_Check(value)) {
94		- return PyObject_Call(exception, value, NULL);
	96	+ exc = PyObject_Call(exception_type, value, NULL);
95	97	}
96	98	else {
97		- return PyObject_CallOneArg(exception, value);
	99	+ exc = PyObject_CallOneArg(exception_type, value);
	100	+ }
	101	+
	102	+ if (exc != NULL && !PyExceptionInstance_Check(exc)) {
	103	+ PyErr_Format(PyExc_TypeError,
	104	+ "calling %R should have returned an instance of "
	105	+ "BaseException, not %s",
	106	+ exception_type, Py_TYPE(exc)->tp_name);
	107	+ Py_CLEAR(exc);
98	108	}
	109	+
	110	+ return exc;
99	111	}
100	112
101	113	void