Issue #29392: Prevent crash when passing invalid arguments into msvcrt module.

1 files changed, 1052 insertions, 0 deletions

diff --git a/Lib/test/test_yield_from.py b/Lib/test/test_yield_from.py
new file mode 100644
index 0000000000..7e9711eaf5
--- /dev/null
+++ b/Lib/test/test_yield_from.py
@@ -0,0 +1,1052 @@
+# -*- coding: utf-8 -*-
+
+"""
+Test suite for PEP 380 implementation
+
+adapted from original tests written by Greg Ewing
+see <http://www.cosc.canterbury.ac.nz/greg.ewing/python/yield-from/YieldFrom-Python3.1.2-rev5.zip>
+"""
+
+import unittest
+import io
+import sys
+import inspect
+import parser
+
+from test.support import captured_stderr, disable_gc, gc_collect
+
+class TestPEP380Operation(unittest.TestCase):
+    """
+    Test semantics.
+    """
+
+    def test_delegation_of_initial_next_to_subgenerator(self):
+        """
+        Test delegation of initial next() call to subgenerator
+        """
+        trace = []
+        def g1():
+            trace.append("Starting g1")
+            yield from g2()
+            trace.append("Finishing g1")
+        def g2():
+            trace.append("Starting g2")
+            yield 42
+            trace.append("Finishing g2")
+        for x in g1():
+            trace.append("Yielded %s" % (x,))
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Starting g2",
+            "Yielded 42",
+            "Finishing g2",
+            "Finishing g1",
+        ])
+
+    def test_raising_exception_in_initial_next_call(self):
+        """
+        Test raising exception in initial next() call
+        """
+        trace = []
+        def g1():
+            try:
+                trace.append("Starting g1")
+                yield from g2()
+            finally:
+                trace.append("Finishing g1")
+        def g2():
+            try:
+                trace.append("Starting g2")
+                raise ValueError("spanish inquisition occurred")
+            finally:
+                trace.append("Finishing g2")
+        try:
+            for x in g1():
+                trace.append("Yielded %s" % (x,))
+        except ValueError as e:
+            self.assertEqual(e.args[0], "spanish inquisition occurred")
+        else:
+            self.fail("subgenerator failed to raise ValueError")
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Starting g2",
+            "Finishing g2",
+            "Finishing g1",
+        ])
+
+    def test_delegation_of_next_call_to_subgenerator(self):
+        """
+        Test delegation of next() call to subgenerator
+        """
+        trace = []
+        def g1():
+            trace.append("Starting g1")
+            yield "g1 ham"
+            yield from g2()
+            yield "g1 eggs"
+            trace.append("Finishing g1")
+        def g2():
+            trace.append("Starting g2")
+            yield "g2 spam"
+            yield "g2 more spam"
+            trace.append("Finishing g2")
+        for x in g1():
+            trace.append("Yielded %s" % (x,))
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Yielded g1 ham",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Yielded g2 more spam",
+            "Finishing g2",
+            "Yielded g1 eggs",
+            "Finishing g1",
+        ])
+
+    def test_raising_exception_in_delegated_next_call(self):
+        """
+        Test raising exception in delegated next() call
+        """
+        trace = []
+        def g1():
+            try:
+                trace.append("Starting g1")
+                yield "g1 ham"
+                yield from g2()
+                yield "g1 eggs"
+            finally:
+                trace.append("Finishing g1")
+        def g2():
+            try:
+                trace.append("Starting g2")
+                yield "g2 spam"
+                raise ValueError("hovercraft is full of eels")
+                yield "g2 more spam"
+            finally:
+                trace.append("Finishing g2")
+        try:
+            for x in g1():
+                trace.append("Yielded %s" % (x,))
+        except ValueError as e:
+            self.assertEqual(e.args[0], "hovercraft is full of eels")
+        else:
+            self.fail("subgenerator failed to raise ValueError")
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Yielded g1 ham",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Finishing g2",
+            "Finishing g1",
+        ])
+
+    def test_delegation_of_send(self):
+        """
+        Test delegation of send()
+        """
+        trace = []
+        def g1():
+            trace.append("Starting g1")
+            x = yield "g1 ham"
+            trace.append("g1 received %s" % (x,))
+            yield from g2()
+            x = yield "g1 eggs"
+            trace.append("g1 received %s" % (x,))
+            trace.append("Finishing g1")
+        def g2():
+            trace.append("Starting g2")
+            x = yield "g2 spam"
+            trace.append("g2 received %s" % (x,))
+            x = yield "g2 more spam"
+            trace.append("g2 received %s" % (x,))
+            trace.append("Finishing g2")
+        g = g1()
+        y = next(g)
+        x = 1
+        try:
+            while 1:
+                y = g.send(x)
+                trace.append("Yielded %s" % (y,))
+                x += 1
+        except StopIteration:
+            pass
+        self.assertEqual(trace,[
+            "Starting g1",
+            "g1 received 1",
+            "Starting g2",
+            "Yielded g2 spam",
+            "g2 received 2",
+            "Yielded g2 more spam",
+            "g2 received 3",
+            "Finishing g2",
+            "Yielded g1 eggs",
+            "g1 received 4",
+            "Finishing g1",
+        ])
+
+    def test_handling_exception_while_delegating_send(self):
+        """
+        Test handling exception while delegating 'send'
+        """
+        trace = []
+        def g1():
+            trace.append("Starting g1")
+            x = yield "g1 ham"
+            trace.append("g1 received %s" % (x,))
+            yield from g2()
+            x = yield "g1 eggs"
+            trace.append("g1 received %s" % (x,))
+            trace.append("Finishing g1")
+        def g2():
+            trace.append("Starting g2")
+            x = yield "g2 spam"
+            trace.append("g2 received %s" % (x,))
+            raise ValueError("hovercraft is full of eels")
+            x = yield "g2 more spam"
+            trace.append("g2 received %s" % (x,))
+            trace.append("Finishing g2")
+        def run():
+            g = g1()
+            y = next(g)
+            x = 1
+            try:
+                while 1:
+                    y = g.send(x)
+                    trace.append("Yielded %s" % (y,))
+                    x += 1
+            except StopIteration:
+                trace.append("StopIteration")
+        self.assertRaises(ValueError,run)
+        self.assertEqual(trace,[
+            "Starting g1",
+            "g1 received 1",
+            "Starting g2",
+            "Yielded g2 spam",
+            "g2 received 2",
+        ])
+
+    def test_delegating_close(self):
+        """
+        Test delegating 'close'
+        """
+        trace = []
+        def g1():
+            try:
+                trace.append("Starting g1")
+                yield "g1 ham"
+                yield from g2()
+                yield "g1 eggs"
+            finally:
+                trace.append("Finishing g1")
+        def g2():
+            try:
+                trace.append("Starting g2")
+                yield "g2 spam"
+                yield "g2 more spam"
+            finally:
+                trace.append("Finishing g2")
+        g = g1()
+        for i in range(2):
+            x = next(g)
+            trace.append("Yielded %s" % (x,))
+        g.close()
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Yielded g1 ham",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Finishing g2",
+            "Finishing g1"
+        ])
+
+    def test_handing_exception_while_delegating_close(self):
+        """
+        Test handling exception while delegating 'close'
+        """
+        trace = []
+        def g1():
+            try:
+                trace.append("Starting g1")
+                yield "g1 ham"
+                yield from g2()
+                yield "g1 eggs"
+            finally:
+                trace.append("Finishing g1")
+        def g2():
+            try:
+                trace.append("Starting g2")
+                yield "g2 spam"
+                yield "g2 more spam"
+            finally:
+                trace.append("Finishing g2")
+                raise ValueError("nybbles have exploded with delight")
+        try:
+            g = g1()
+            for i in range(2):
+                x = next(g)
+                trace.append("Yielded %s" % (x,))
+            g.close()
+        except ValueError as e:
+            self.assertEqual(e.args[0], "nybbles have exploded with delight")
+            self.assertIsInstance(e.__context__, GeneratorExit)
+        else:
+            self.fail("subgenerator failed to raise ValueError")
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Yielded g1 ham",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Finishing g2",
+            "Finishing g1",
+        ])
+
+    def test_delegating_throw(self):
+        """
+        Test delegating 'throw'
+        """
+        trace = []
+        def g1():
+            try:
+                trace.append("Starting g1")
+                yield "g1 ham"
+                yield from g2()
+                yield "g1 eggs"
+            finally:
+                trace.append("Finishing g1")
+        def g2():
+            try:
+                trace.append("Starting g2")
+                yield "g2 spam"
+                yield "g2 more spam"
+            finally:
+                trace.append("Finishing g2")
+        try:
+            g = g1()
+            for i in range(2):
+                x = next(g)
+                trace.append("Yielded %s" % (x,))
+            e = ValueError("tomato ejected")
+            g.throw(e)
+        except ValueError as e:
+            self.assertEqual(e.args[0], "tomato ejected")
+        else:
+            self.fail("subgenerator failed to raise ValueError")
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Yielded g1 ham",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Finishing g2",
+            "Finishing g1",
+        ])
+
+    def test_value_attribute_of_StopIteration_exception(self):
+        """
+        Test 'value' attribute of StopIteration exception
+        """
+        trace = []
+        def pex(e):
+            trace.append("%s: %s" % (e.__class__.__name__, e))
+            trace.append("value = %s" % (e.value,))
+        e = StopIteration()
+        pex(e)
+        e = StopIteration("spam")
+        pex(e)
+        e.value = "eggs"
+        pex(e)
+        self.assertEqual(trace,[
+            "StopIteration: ",
+            "value = None",
+            "StopIteration: spam",
+            "value = spam",
+            "StopIteration: spam",
+            "value = eggs",
+        ])
+
+
+    def test_exception_value_crash(self):
+        # There used to be a refcount error when the return value
+        # stored in the StopIteration has a refcount of 1.
+        def g1():
+            yield from g2()
+        def g2():
+            yield "g2"
+            return [42]
+        self.assertEqual(list(g1()), ["g2"])
+
+
+    def test_generator_return_value(self):
+        """
+        Test generator return value
+        """
+        trace = []
+        def g1():
+            trace.append("Starting g1")
+            yield "g1 ham"
+            ret = yield from g2()
+            trace.append("g2 returned %r" % (ret,))
+            for v in 1, (2,), StopIteration(3):
+                ret = yield from g2(v)
+                trace.append("g2 returned %r" % (ret,))
+            yield "g1 eggs"
+            trace.append("Finishing g1")
+        def g2(v = None):
+            trace.append("Starting g2")
+            yield "g2 spam"
+            yield "g2 more spam"
+            trace.append("Finishing g2")
+            if v:
+                return v
+        for x in g1():
+            trace.append("Yielded %s" % (x,))
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Yielded g1 ham",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Yielded g2 more spam",
+            "Finishing g2",
+            "g2 returned None",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Yielded g2 more spam",
+            "Finishing g2",
+            "g2 returned 1",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Yielded g2 more spam",
+            "Finishing g2",
+            "g2 returned (2,)",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Yielded g2 more spam",
+            "Finishing g2",
+            "g2 returned StopIteration(3,)",
+            "Yielded g1 eggs",
+            "Finishing g1",
+        ])
+
+    def test_delegation_of_next_to_non_generator(self):
+        """
+        Test delegation of next() to non-generator
+        """
+        trace = []
+        def g():
+            yield from range(3)
+        for x in g():
+            trace.append("Yielded %s" % (x,))
+        self.assertEqual(trace,[
+            "Yielded 0",
+            "Yielded 1",
+            "Yielded 2",
+        ])
+
+
+    def test_conversion_of_sendNone_to_next(self):
+        """
+        Test conversion of send(None) to next()
+        """
+        trace = []
+        def g():
+            yield from range(3)
+        gi = g()
+        for x in range(3):
+            y = gi.send(None)
+            trace.append("Yielded: %s" % (y,))
+        self.assertEqual(trace,[
+            "Yielded: 0",
+            "Yielded: 1",
+            "Yielded: 2",
+        ])
+
+    def test_delegation_of_close_to_non_generator(self):
+        """
+        Test delegation of close() to non-generator
+        """
+        trace = []
+        def g():
+            try:
+                trace.append("starting g")
+                yield from range(3)
+                trace.append("g should not be here")
+            finally:
+                trace.append("finishing g")
+        gi = g()
+        next(gi)
+        with captured_stderr() as output:
+            gi.close()
+        self.assertEqual(output.getvalue(), '')
+        self.assertEqual(trace,[
+            "starting g",
+            "finishing g",
+        ])
+
+    def test_delegating_throw_to_non_generator(self):
+        """
+        Test delegating 'throw' to non-generator
+        """
+        trace = []
+        def g():
+            try:
+                trace.append("Starting g")
+                yield from range(10)
+            finally:
+                trace.append("Finishing g")
+        try:
+            gi = g()
+            for i in range(5):
+                x = next(gi)
+                trace.append("Yielded %s" % (x,))
+            e = ValueError("tomato ejected")
+            gi.throw(e)
+        except ValueError as e:
+            self.assertEqual(e.args[0],"tomato ejected")
+        else:
+            self.fail("subgenerator failed to raise ValueError")
+        self.assertEqual(trace,[
+            "Starting g",
+            "Yielded 0",
+            "Yielded 1",
+            "Yielded 2",
+            "Yielded 3",
+            "Yielded 4",
+            "Finishing g",
+        ])
+
+    def test_attempting_to_send_to_non_generator(self):
+        """
+        Test attempting to send to non-generator
+        """
+        trace = []
+        def g():
+            try:
+                trace.append("starting g")
+                yield from range(3)
+                trace.append("g should not be here")
+            finally:
+                trace.append("finishing g")
+        try:
+            gi = g()
+            next(gi)
+            for x in range(3):
+                y = gi.send(42)
+                trace.append("Should not have yielded: %s" % (y,))
+        except AttributeError as e:
+            self.assertIn("send", e.args[0])
+        else:
+            self.fail("was able to send into non-generator")
+        self.assertEqual(trace,[
+            "starting g",
+            "finishing g",
+        ])
+
+    def test_broken_getattr_handling(self):
+        """
+        Test subiterator with a broken getattr implementation
+        """
+        class Broken:
+            def __iter__(self):
+                return self
+            def __next__(self):
+                return 1
+            def __getattr__(self, attr):
+                1/0
+
+        def g():
+            yield from Broken()
+
+        with self.assertRaises(ZeroDivisionError):
+            gi = g()
+            self.assertEqual(next(gi), 1)
+            gi.send(1)
+
+        with self.assertRaises(ZeroDivisionError):
+            gi = g()
+            self.assertEqual(next(gi), 1)
+            gi.throw(AttributeError)
+
+        with captured_stderr() as output:
+            gi = g()
+            self.assertEqual(next(gi), 1)
+            gi.close()
+        self.assertIn('ZeroDivisionError', output.getvalue())
+
+    def test_exception_in_initial_next_call(self):
+        """
+        Test exception in initial next() call
+        """
+        trace = []
+        def g1():
+            trace.append("g1 about to yield from g2")
+            yield from g2()
+            trace.append("g1 should not be here")
+        def g2():
+            yield 1/0
+        def run():
+            gi = g1()
+            next(gi)
+        self.assertRaises(ZeroDivisionError,run)
+        self.assertEqual(trace,[
+            "g1 about to yield from g2"
+        ])
+
+    def test_attempted_yield_from_loop(self):
+        """
+        Test attempted yield-from loop
+        """
+        trace = []
+        def g1():
+            trace.append("g1: starting")
+            yield "y1"
+            trace.append("g1: about to yield from g2")
+            yield from g2()
+            trace.append("g1 should not be here")
+
+        def g2():
+            trace.append("g2: starting")
+            yield "y2"
+            trace.append("g2: about to yield from g1")
+            yield from gi
+            trace.append("g2 should not be here")
+        try:
+            gi = g1()
+            for y in gi:
+                trace.append("Yielded: %s" % (y,))
+        except ValueError as e:
+            self.assertEqual(e.args[0],"generator already executing")
+        else:
+            self.fail("subgenerator didn't raise ValueError")
+        self.assertEqual(trace,[
+            "g1: starting",
+            "Yielded: y1",
+            "g1: about to yield from g2",
+            "g2: starting",
+            "Yielded: y2",
+            "g2: about to yield from g1",
+        ])
+
+    def test_returning_value_from_delegated_throw(self):
+        """
+        Test returning value from delegated 'throw'
+        """
+        trace = []
+        def g1():
+            try:
+                trace.append("Starting g1")
+                yield "g1 ham"
+                yield from g2()
+                yield "g1 eggs"
+            finally:
+                trace.append("Finishing g1")
+        def g2():
+            try:
+                trace.append("Starting g2")
+                yield "g2 spam"
+                yield "g2 more spam"
+            except LunchError:
+                trace.append("Caught LunchError in g2")
+                yield "g2 lunch saved"
+                yield "g2 yet more spam"
+        class LunchError(Exception):
+            pass
+        g = g1()
+        for i in range(2):
+            x = next(g)
+            trace.append("Yielded %s" % (x,))
+        e = LunchError("tomato ejected")
+        g.throw(e)
+        for x in g:
+            trace.append("Yielded %s" % (x,))
+        self.assertEqual(trace,[
+            "Starting g1",
+            "Yielded g1 ham",
+            "Starting g2",
+            "Yielded g2 spam",
+            "Caught LunchError in g2",
+            "Yielded g2 yet more spam",
+            "Yielded g1 eggs",
+            "Finishing g1",
+        ])
+
+    def test_next_and_return_with_value(self):
+        """
+        Test next and return with value
+        """
+        trace = []
+        def f(r):
+            gi = g(r)
+            next(gi)
+            try:
+                trace.append("f resuming g")
+                next(gi)
+                trace.append("f SHOULD NOT BE HERE")
+            except StopIteration as e:
+                trace.append("f caught %r" % (e,))
+        def g(r):
+            trace.append("g starting")
+            yield
+            trace.append("g returning %r" % (r,))
+            return r
+        f(None)
+        f(1)
+        f((2,))
+        f(StopIteration(3))
+        self.assertEqual(trace,[
+            "g starting",
+            "f resuming g",
+            "g returning None",
+            "f caught StopIteration()",
+            "g starting",
+            "f resuming g",
+            "g returning 1",
+            "f caught StopIteration(1,)",
+            "g starting",
+            "f resuming g",
+            "g returning (2,)",
+            "f caught StopIteration((2,),)",
+            "g starting",
+            "f resuming g",
+            "g returning StopIteration(3,)",
+            "f caught StopIteration(StopIteration(3,),)",
+        ])
+
+    def test_send_and_return_with_value(self):
+        """
+        Test send and return with value
+        """
+        trace = []
+        def f(r):
+            gi = g(r)
+            next(gi)
+            try:
+                trace.append("f sending spam to g")
+                gi.send("spam")
+                trace.append("f SHOULD NOT BE HERE")
+            except StopIteration as e:
+                trace.append("f caught %r" % (e,))
+        def g(r):
+            trace.append("g starting")
+            x = yield
+            trace.append("g received %r" % (x,))
+            trace.append("g returning %r" % (r,))
+            return r
+        f(None)
+        f(1)
+        f((2,))
+        f(StopIteration(3))
+        self.assertEqual(trace, [
+            "g starting",
+            "f sending spam to g",
+            "g received 'spam'",
+            "g returning None",
+            "f caught StopIteration()",
+            "g starting",
+            "f sending spam to g",
+            "g received 'spam'",
+            "g returning 1",
+            'f caught StopIteration(1,)',
+            'g starting',
+            'f sending spam to g',
+            "g received 'spam'",
+            'g returning (2,)',
+            'f caught StopIteration((2,),)',
+            'g starting',
+            'f sending spam to g',
+            "g received 'spam'",
+            'g returning StopIteration(3,)',
+            'f caught StopIteration(StopIteration(3,),)'
+        ])
+
+    def test_catching_exception_from_subgen_and_returning(self):
+        """
+        Test catching an exception thrown into a
+        subgenerator and returning a value
+        """
+        def inner():
+            try:
+                yield 1
+            except ValueError:
+                trace.append("inner caught ValueError")
+            return value
+
+        def outer():
+            v = yield from inner()
+            trace.append("inner returned %r to outer" % (v,))
+            yield v
+
+        for value in 2, (2,), StopIteration(2):
+            trace = []
+            g = outer()
+            trace.append(next(g))
+            trace.append(repr(g.throw(ValueError)))
+            self.assertEqual(trace, [
+                1,
+                "inner caught ValueError",
+                "inner returned %r to outer" % (value,),
+                repr(value),
+            ])
+
+    def test_throwing_GeneratorExit_into_subgen_that_returns(self):
+        """
+        Test throwing GeneratorExit into a subgenerator that
+        catches it and returns normally.
+        """
+        trace = []
+        def f():
+            try:
+                trace.append("Enter f")
+                yield
+                trace.append("Exit f")
+            except GeneratorExit:
+                return
+        def g():
+            trace.append("Enter g")
+            yield from f()
+            trace.append("Exit g")
+        try:
+            gi = g()
+            next(gi)
+            gi.throw(GeneratorExit)
+        except GeneratorExit:
+            pass
+        else:
+            self.fail("subgenerator failed to raise GeneratorExit")
+        self.assertEqual(trace,[
+            "Enter g",
+            "Enter f",
+        ])
+
+    def test_throwing_GeneratorExit_into_subgenerator_that_yields(self):
+        """
+        Test throwing GeneratorExit into a subgenerator that
+        catches it and yields.
+        """
+        trace = []
+        def f():
+            try:
+                trace.append("Enter f")
+                yield
+                trace.append("Exit f")
+            except GeneratorExit:
+                yield
+        def g():
+            trace.append("Enter g")
+            yield from f()
+            trace.append("Exit g")
+        try:
+            gi = g()
+            next(gi)
+            gi.throw(GeneratorExit)
+        except RuntimeError as e:
+            self.assertEqual(e.args[0], "generator ignored GeneratorExit")
+        else:
+            self.fail("subgenerator failed to raise GeneratorExit")
+        self.assertEqual(trace,[
+            "Enter g",
+            "Enter f",
+        ])
+
+    def test_throwing_GeneratorExit_into_subgen_that_raises(self):
+        """
+        Test throwing GeneratorExit into a subgenerator that
+        catches it and raises a different exception.
+        """
+        trace = []
+        def f():
+            try:
+                trace.append("Enter f")
+                yield
+                trace.append("Exit f")
+            except GeneratorExit:
+                raise ValueError("Vorpal bunny encountered")
+        def g():
+            trace.append("Enter g")
+            yield from f()
+            trace.append("Exit g")
+        try:
+            gi = g()
+            next(gi)
+            gi.throw(GeneratorExit)
+        except ValueError as e:
+            self.assertEqual(e.args[0], "Vorpal bunny encountered")
+            self.assertIsInstance(e.__context__, GeneratorExit)
+        else:
+            self.fail("subgenerator failed to raise ValueError")
+        self.assertEqual(trace,[
+            "Enter g",
+            "Enter f",
+        ])
+
+    def test_yield_from_empty(self):
+        def g():
+            yield from ()
+        self.assertRaises(StopIteration, next, g())
+
+    def test_delegating_generators_claim_to_be_running(self):
+        # Check with basic iteration
+        def one():
+            yield 0
+            yield from two()
+            yield 3
+        def two():
+            yield 1
+            try:
+                yield from g1
+            except ValueError:
+                pass
+            yield 2
+        g1 = one()
+        self.assertEqual(list(g1), [0, 1, 2, 3])
+        # Check with send
+        g1 = one()
+        res = [next(g1)]
+        try:
+            while True:
+                res.append(g1.send(42))
+        except StopIteration:
+            pass
+        self.assertEqual(res, [0, 1, 2, 3])
+        # Check with throw
+        class MyErr(Exception):
+            pass
+        def one():
+            try:
+                yield 0
+            except MyErr:
+                pass
+            yield from two()
+            try:
+                yield 3
+            except MyErr:
+                pass
+        def two():
+            try:
+                yield 1
+            except MyErr:
+                pass
+            try:
+                yield from g1
+            except ValueError:
+                pass
+            try:
+                yield 2
+            except MyErr:
+                pass
+        g1 = one()
+        res = [next(g1)]
+        try:
+            while True:
+                res.append(g1.throw(MyErr))
+        except StopIteration:
+            pass
+        # Check with close
+        class MyIt(object):
+            def __iter__(self):
+                return self
+            def __next__(self):
+                return 42
+            def close(self_):
+                self.assertTrue(g1.gi_running)
+                self.assertRaises(ValueError, next, g1)
+        def one():
+            yield from MyIt()
+        g1 = one()
+        next(g1)
+        g1.close()
+
+    def test_delegator_is_visible_to_debugger(self):
+        def call_stack():
+            return [f[3] for f in inspect.stack()]
+
+        def gen():
+            yield call_stack()
+            yield call_stack()
+            yield call_stack()
+
+        def spam(g):
+            yield from g
+
+        def eggs(g):
+            yield from g
+
+        for stack in spam(gen()):
+            self.assertTrue('spam' in stack)
+
+        for stack in spam(eggs(gen())):
+            self.assertTrue('spam' in stack and 'eggs' in stack)
+
+    def test_custom_iterator_return(self):
+        # See issue #15568
+        class MyIter:
+            def __iter__(self):
+                return self
+            def __next__(self):
+                raise StopIteration(42)
+        def gen():
+            nonlocal ret
+            ret = yield from MyIter()
+        ret = None
+        list(gen())
+        self.assertEqual(ret, 42)
+
+    def test_close_with_cleared_frame(self):
+        # See issue #17669.
+        #
+        # Create a stack of generators: outer() delegating to inner()
+        # delegating to innermost(). The key point is that the instance of
+        # inner is created first: this ensures that its frame appears before
+        # the instance of outer in the GC linked list.
+        #
+        # At the gc.collect call:
+        #   - frame_clear is called on the inner_gen frame.
+        #   - gen_dealloc is called on the outer_gen generator (the only
+        #     reference is in the frame's locals).
+        #   - gen_close is called on the outer_gen generator.
+        #   - gen_close_iter is called to close the inner_gen generator, which
+        #     in turn calls gen_close, and gen_yf.
+        #
+        # Previously, gen_yf would crash since inner_gen's frame had been
+        # cleared (and in particular f_stacktop was NULL).
+
+        def innermost():
+            yield
+        def inner():
+            outer_gen = yield
+            yield from innermost()
+        def outer():
+            inner_gen = yield
+            yield from inner_gen
+
+        with disable_gc():
+            inner_gen = inner()
+            outer_gen = outer()
+            outer_gen.send(None)
+            outer_gen.send(inner_gen)
+            outer_gen.send(outer_gen)
+
+            del outer_gen
+            del inner_gen
+            gc_collect()
+
+    def test_send_tuple_with_custom_generator(self):
+        # See issue #21209.
+        class MyGen:
+            def __iter__(self):
+                return self
+            def __next__(self):
+                return 42
+            def send(self, what):
+                nonlocal v
+                v = what
+                return None
+        def outer():
+            v = yield from MyGen()
+        g = outer()
+        next(g)
+        v = None
+        g.send((1, 2, 3, 4))
+        self.assertEqual(v, (1, 2, 3, 4))
+
+
+if __name__ == '__main__':
+    unittest.main()