From 99c72326d245fb604609a87a51ef1ad0845467b7 Mon Sep 17 00:00:00 2001 From: Mark Shannon Date: Wed, 8 Dec 2021 14:46:32 +0000 Subject: [PATCH] [3.10] bpo-46009: Do not exhaust generator when send() method raises (GH-29986). (GH-29988) * [3.10] bpo-46009: Do not exhaust generator when send() method raises (GH-29986). (cherry picked from commit 69806b9516dbe092381f3ef884c7c64bb9b8414a) Co-authored-by: Mark Shannon * Rename variable after cherry-pick. * Add NULL check. --- Doc/library/dis.rst | 5 ++--- Lib/test/test_generators.py | 8 ++++++++ .../2021-12-08-11-06-53.bpo-46009.cL8pH0.rst | 5 +++++ Objects/genobject.c | 13 ++++++++++++ Python/ceval.c | 20 ++----------------- 5 files changed, 30 insertions(+), 21 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2021-12-08-11-06-53.bpo-46009.cL8pH0.rst diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst index e7e67daae525..74820f9bdb57 100644 --- a/Doc/library/dis.rst +++ b/Doc/library/dis.rst @@ -1252,9 +1252,8 @@ All of the following opcodes use their arguments. .. opcode:: GEN_START (kind) - Pops TOS. If TOS was not ``None``, raises an exception. The ``kind`` - operand corresponds to the type of generator or coroutine and determines - the error message. The legal kinds are 0 for generator, 1 for coroutine, + Pops TOS. The ``kind`` operand corresponds to the type of generator or + coroutine. The legal kinds are 0 for generator, 1 for coroutine, and 2 for async generator. .. versionadded:: 3.10 diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py index d14c757c7b6e..3bf5f3b7438e 100644 --- a/Lib/test/test_generators.py +++ b/Lib/test/test_generators.py @@ -161,6 +161,14 @@ class GeneratorTest(unittest.TestCase): with self.assertRaises((TypeError, pickle.PicklingError)): pickle.dumps(g, proto) + def test_send_non_none_to_new_gen(self): + def f(): + yield 1 + g = f() + with self.assertRaises(TypeError): + g.send(0) + self.assertEqual(next(g), 1) + class ExceptionTest(unittest.TestCase): # Tests for the issue #23353: check that the currently handled exception diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-12-08-11-06-53.bpo-46009.cL8pH0.rst b/Misc/NEWS.d/next/Core and Builtins/2021-12-08-11-06-53.bpo-46009.cL8pH0.rst new file mode 100644 index 000000000000..a80e66b7c645 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2021-12-08-11-06-53.bpo-46009.cL8pH0.rst @@ -0,0 +1,5 @@ +Restore behavior from 3.9 and earlier when sending non-None to newly started +generator. In 3.9 this did not affect the state of the generator. In 3.10.0 +and 3.10.1 ``gen_func().send(0)`` is equivalent to +``gen_func().throw(TypeError(...)`` which exhausts the generator. In 3.10.2 +onward, the behavior has been reverted to that of 3.9. diff --git a/Objects/genobject.c b/Objects/genobject.c index 3ac38de0c311..33fc4a592492 100644 --- a/Objects/genobject.c +++ b/Objects/genobject.c @@ -145,6 +145,19 @@ gen_send_ex2(PyGenObject *gen, PyObject *arg, PyObject **presult, PyObject *result; *presult = NULL; + if (f != NULL && f->f_lasti < 0 && arg && arg != Py_None) { + const char *msg = "can't send non-None value to a " + "just-started generator"; + if (PyCoro_CheckExact(gen)) { + msg = NON_INIT_CORO_MSG; + } + else if (PyAsyncGen_CheckExact(gen)) { + msg = "can't send non-None value to a " + "just-started async generator"; + } + PyErr_SetString(PyExc_TypeError, msg); + return PYGEN_ERROR; + } if (f != NULL && _PyFrame_IsExecuting(f)) { const char *msg = "generator already executing"; if (PyCoro_CheckExact(gen)) { diff --git a/Python/ceval.c b/Python/ceval.c index 624baf537518..8ad1713b78c0 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -2649,25 +2649,9 @@ main_loop: case TARGET(GEN_START): { PyObject *none = POP(); + assert(none == Py_None); + assert(oparg < 3); Py_DECREF(none); - if (!Py_IsNone(none)) { - if (oparg > 2) { - _PyErr_SetString(tstate, PyExc_SystemError, - "Illegal kind for GEN_START"); - } - else { - static const char *gen_kind[3] = { - "generator", - "coroutine", - "async generator" - }; - _PyErr_Format(tstate, PyExc_TypeError, - "can't send non-None value to a " - "just-started %s", - gen_kind[oparg]); - } - goto error; - } DISPATCH(); } -- 2.47.3