From 70ed7a8d7fde75afab8c4d55fa2dee2fe34fc750 Mon Sep 17 00:00:00 2001 From: Chris Jerdonek Date: Wed, 29 Apr 2020 22:21:08 -0700 Subject: [PATCH 1/2] Add a failing test for issue 29587. --- Lib/test/test_generators.py | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py index 3e42bc6b69a819..4d96f44b150622 100644 --- a/Lib/test/test_generators.py +++ b/Lib/test/test_generators.py @@ -316,6 +316,23 @@ def g(): self.assertEqual(cm.exception.value.value, 2) +class GeneratorThrowTest(unittest.TestCase): + + def test_exception_context_set(self): + def f(): + try: + raise KeyError('a') + except Exception: + yield + + gen = f() + gen.send(None) + with self.assertRaises(ValueError) as cm: + gen.throw(ValueError) + context = cm.exception.__context__ + self.assertEqual((type(context), context.args), (KeyError, ('a',))) + + class YieldFromTests(unittest.TestCase): def test_generator_gi_yieldfrom(self): def a(): From b377e49d9c64af14ec1b3d3a2960edb2ec63dc0b Mon Sep 17 00:00:00 2001 From: Chris Jerdonek Date: Thu, 30 Apr 2020 00:31:39 -0700 Subject: [PATCH 2/2] bpo-29587: set exc.__context__ when calling gen.throw() (GH-19811) Before this commit, if an exception was active inside a generator when calling gen.throw(), then that exception was lost (i.e. there was no implicit exception chaining). This commit fixes that. --- .../2020-04-30-00-50-25.bpo-29587.oEwSq.rst | 1 + Objects/genobject.c | 6 ++++++ 2 files changed, 7 insertions(+) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2020-04-30-00-50-25.bpo-29587.oEwSq.rst diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-04-30-00-50-25.bpo-29587.oEwSq.rst b/Misc/NEWS.d/next/Core and Builtins/2020-04-30-00-50-25.bpo-29587.oEwSq.rst new file mode 100644 index 00000000000000..f44aa360cc2ef3 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2020-04-30-00-50-25.bpo-29587.oEwSq.rst @@ -0,0 +1 @@ +Enable implicit exception chaining when calling :meth:`generator.throw`. diff --git a/Objects/genobject.c b/Objects/genobject.c index 6e36690b65148a..289ed79aa28a65 100644 --- a/Objects/genobject.c +++ b/Objects/genobject.c @@ -512,6 +512,12 @@ _gen_throw(PyGenObject *gen, int close_on_genexit, } PyErr_Restore(typ, val, tb); + if (gen->gi_exc_state.exc_type) { + Py_INCREF(gen->gi_exc_state.exc_type); + Py_XINCREF(gen->gi_exc_state.exc_value); + Py_XINCREF(gen->gi_exc_state.exc_traceback); + _PyErr_ChainExceptions(gen->gi_exc_state.exc_type, gen->gi_exc_state.exc_value, gen->gi_exc_state.exc_traceback); + } return gen_send_ex(gen, Py_None, 1, 0); failed_throw: