From feec49c40736fc05626a183a8d14c4ebbea5ae28 Mon Sep 17 00:00:00 2001 From: Mark Shannon Date: Wed, 8 Feb 2023 09:31:12 +0000 Subject: [PATCH] GH-101578: Normalize the current exception (GH-101607) * Make sure that the current exception is always normalized. * Remove redundant type and traceback fields for the current exception. * Add new API functions: PyErr_GetRaisedException, PyErr_SetRaisedException * Add new API functions: PyException_GetArgs, PyException_SetArgs --- Doc/c-api/exceptions.rst | 79 +++++- Doc/data/stable_abi.dat | 4 + Include/cpython/pyerrors.h | 1 + Include/cpython/pystate.h | 4 +- Include/internal/pycore_pyerrors.h | 11 +- Include/pyerrors.h | 6 + Lib/test/test_capi/test_misc.py | 39 +++ Lib/test/test_exceptions.py | 8 +- Lib/test/test_stable_abi_ctypes.py | 4 + ...-02-06-16-14-30.gh-issue-101578.PW5fA9.rst | 13 + Misc/stable_abi.toml | 9 + Modules/_testcapi/heaptype.c | 24 +- Modules/_testcapimodule.c | 37 +++ Modules/gcmodule.c | 5 +- Objects/dictobject.c | 6 +- Objects/exceptions.c | 75 +++++- Objects/object.c | 12 +- PC/python3dll.c | 4 + Parser/pegen.c | 15 +- Python/bytecodes.c | 4 +- Python/ceval.c | 12 +- Python/errors.c | 227 +++++++++++------- Python/generated_cases.c.h | 4 +- Python/import.c | 7 + Python/initconfig.c | 5 +- Python/pystate.c | 4 +- Python/pythonrun.c | 11 +- Python/sysmodule.c | 10 +- Python/traceback.c | 9 +- 29 files changed, 477 insertions(+), 172 deletions(-) create mode 100644 Misc/NEWS.d/next/C API/2023-02-06-16-14-30.gh-issue-101578.PW5fA9.rst diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst index 087e0a61d12..de9b15edd68 100644 --- a/Doc/c-api/exceptions.rst +++ b/Doc/c-api/exceptions.rst @@ -400,8 +400,61 @@ Querying the error indicator recursively in subtuples) are searched for a match. +.. c:function:: PyObject *PyErr_GetRaisedException(void) + + Returns the exception currently being raised, clearing the exception at + the same time. Do not confuse this with the exception currently being + handled which can be accessed with :c:func:`PyErr_GetHandledException`. + + .. note:: + + This function is normally only used by code that needs to catch exceptions or + by code that needs to save and restore the error indicator temporarily, e.g.:: + + { + PyObject *exc = PyErr_GetRaisedException(); + + /* ... code that might produce other errors ... */ + + PyErr_SetRaisedException(exc); + } + + .. versionadded:: 3.12 + + +.. c:function:: void PyErr_SetRaisedException(PyObject *exc) + + Sets the exception currently being raised ``exc``. + If the exception is already set, it is cleared first. + + ``exc`` must be a valid exception. + (Violating this rules will cause subtle problems later.) + This call consumes a reference to the ``exc`` object: you must own a + reference to that object before the call and after the call you no longer own + that reference. + (If you don't understand this, don't use this function. I warned you.) + + .. note:: + + This function is normally only used by code that needs to save and restore the + error indicator temporarily. Use :c:func:`PyErr_GetRaisedException` to save + the current exception, e.g.:: + + { + PyObject *exc = PyErr_GetRaisedException(); + + /* ... code that might produce other errors ... */ + + PyErr_SetRaisedException(exc); + } + + .. versionadded:: 3.12 + + .. c:function:: void PyErr_Fetch(PyObject **ptype, PyObject **pvalue, PyObject **ptraceback) + As of 3.12, this function is deprecated. Use :c:func:`PyErr_GetRaisedException` instead. + Retrieve the error indicator into three variables whose addresses are passed. If the error indicator is not set, set all three variables to ``NULL``. If it is set, it will be cleared and you own a reference to each object retrieved. The @@ -421,10 +474,14 @@ Querying the error indicator PyErr_Restore(type, value, traceback); } + .. deprecated:: 3.12 + .. c:function:: void PyErr_Restore(PyObject *type, PyObject *value, PyObject *traceback) - Set the error indicator from the three objects. If the error indicator is + As of 3.12, this function is deprecated. Use :c:func:`PyErr_SetRaisedException` instead. + + Set the error indicator from the three objects. If the error indicator is already set, it is cleared first. If the objects are ``NULL``, the error indicator is cleared. Do not pass a ``NULL`` type and non-``NULL`` value or traceback. The exception type should be a class. Do not pass an invalid @@ -440,9 +497,15 @@ Querying the error indicator error indicator temporarily. Use :c:func:`PyErr_Fetch` to save the current error indicator. + .. deprecated:: 3.12 + .. c:function:: void PyErr_NormalizeException(PyObject **exc, PyObject **val, PyObject **tb) + As of 3.12, this function is deprecated. + Use :c:func:`PyErr_GetRaisedException` instead of :c:func:`PyErr_Fetch` to avoid + any possible de-normalization. + Under certain circumstances, the values returned by :c:func:`PyErr_Fetch` below can be "unnormalized", meaning that ``*exc`` is a class object but ``*val`` is not an instance of the same class. This function can be used to instantiate @@ -459,6 +522,8 @@ Querying the error indicator PyException_SetTraceback(val, tb); } + .. deprecated:: 3.12 + .. c:function:: PyObject* PyErr_GetHandledException(void) @@ -704,6 +769,18 @@ Exception Objects :attr:`__suppress_context__` is implicitly set to ``True`` by this function. +.. c:function:: PyObject* PyException_GetArgs(PyObject *ex) + + Return args of the given exception as a new reference, + as accessible from Python through :attr:`args`. + + +.. c:function:: void PyException_SetArgs(PyObject *ex, PyObject *args) + + Set the args of the given exception, + as accessible from Python through :attr:`args`. + + .. _unicodeexceptions: Unicode Exception Objects diff --git a/Doc/data/stable_abi.dat b/Doc/data/stable_abi.dat index 53895bbced8..68ab0b5061f 100644 --- a/Doc/data/stable_abi.dat +++ b/Doc/data/stable_abi.dat @@ -139,6 +139,7 @@ function,PyErr_Format,3.2,, function,PyErr_FormatV,3.5,, function,PyErr_GetExcInfo,3.7,, function,PyErr_GetHandledException,3.11,, +function,PyErr_GetRaisedException,3.12,, function,PyErr_GivenExceptionMatches,3.2,, function,PyErr_NewException,3.2,, function,PyErr_NewExceptionWithDoc,3.2,, @@ -168,6 +169,7 @@ function,PyErr_SetInterrupt,3.2,, function,PyErr_SetInterruptEx,3.10,, function,PyErr_SetNone,3.2,, function,PyErr_SetObject,3.2,, +function,PyErr_SetRaisedException,3.12,, function,PyErr_SetString,3.2,, function,PyErr_SyntaxLocation,3.2,, function,PyErr_SyntaxLocationEx,3.7,, @@ -266,9 +268,11 @@ var,PyExc_Warning,3.2,, var,PyExc_WindowsError,3.7,on Windows, var,PyExc_ZeroDivisionError,3.2,, function,PyExceptionClass_Name,3.8,, +function,PyException_GetArgs,3.12,, function,PyException_GetCause,3.2,, function,PyException_GetContext,3.2,, function,PyException_GetTraceback,3.2,, +function,PyException_SetArgs,3.12,, function,PyException_SetCause,3.2,, function,PyException_SetContext,3.2,, function,PyException_SetTraceback,3.2,, diff --git a/Include/cpython/pyerrors.h b/Include/cpython/pyerrors.h index 14134166779..0d9cc9922f7 100644 --- a/Include/cpython/pyerrors.h +++ b/Include/cpython/pyerrors.h @@ -99,6 +99,7 @@ PyAPI_FUNC(void) _PyErr_GetExcInfo(PyThreadState *, PyObject **, PyObject **, Py /* Context manipulation (PEP 3134) */ PyAPI_FUNC(void) _PyErr_ChainExceptions(PyObject *, PyObject *, PyObject *); +PyAPI_FUNC(void) _PyErr_ChainExceptions1(PyObject *); /* Like PyErr_Format(), but saves current exception as __context__ and __cause__. diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h index f5db52f76e8..be1fcb61fa2 100644 --- a/Include/cpython/pystate.h +++ b/Include/cpython/pystate.h @@ -166,9 +166,7 @@ struct _ts { PyObject *c_traceobj; /* The exception currently being raised */ - PyObject *curexc_type; - PyObject *curexc_value; - PyObject *curexc_traceback; + PyObject *current_exception; /* Pointer to the top of the exception stack for the exceptions * we may be currently handling. (See _PyErr_StackItem above.) diff --git a/Include/internal/pycore_pyerrors.h b/Include/internal/pycore_pyerrors.h index 66f37942ef9..1bb4a9aa103 100644 --- a/Include/internal/pycore_pyerrors.h +++ b/Include/internal/pycore_pyerrors.h @@ -20,7 +20,10 @@ extern void _PyErr_FiniTypes(PyInterpreterState *); static inline PyObject* _PyErr_Occurred(PyThreadState *tstate) { assert(tstate != NULL); - return tstate->curexc_type; + if (tstate->current_exception == NULL) { + return NULL; + } + return (PyObject *)Py_TYPE(tstate->current_exception); } static inline void _PyErr_ClearExcState(_PyErr_StackItem *exc_state) @@ -37,10 +40,16 @@ PyAPI_FUNC(void) _PyErr_Fetch( PyObject **value, PyObject **traceback); +extern PyObject * +_PyErr_GetRaisedException(PyThreadState *tstate); + PyAPI_FUNC(int) _PyErr_ExceptionMatches( PyThreadState *tstate, PyObject *exc); +void +_PyErr_SetRaisedException(PyThreadState *tstate, PyObject *exc); + PyAPI_FUNC(void) _PyErr_Restore( PyThreadState *tstate, PyObject *type, diff --git a/Include/pyerrors.h b/Include/pyerrors.h index d5ac6af5b32..d089fa71779 100644 --- a/Include/pyerrors.h +++ b/Include/pyerrors.h @@ -18,6 +18,8 @@ PyAPI_FUNC(PyObject *) PyErr_Occurred(void); PyAPI_FUNC(void) PyErr_Clear(void); PyAPI_FUNC(void) PyErr_Fetch(PyObject **, PyObject **, PyObject **); PyAPI_FUNC(void) PyErr_Restore(PyObject *, PyObject *, PyObject *); +PyAPI_FUNC(PyObject *) PyErr_GetRaisedException(void); +PyAPI_FUNC(void) PyErr_SetRaisedException(PyObject *); #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030b0000 PyAPI_FUNC(PyObject*) PyErr_GetHandledException(void); PyAPI_FUNC(void) PyErr_SetHandledException(PyObject *); @@ -51,6 +53,10 @@ PyAPI_FUNC(void) PyException_SetCause(PyObject *, PyObject *); PyAPI_FUNC(PyObject *) PyException_GetContext(PyObject *); PyAPI_FUNC(void) PyException_SetContext(PyObject *, PyObject *); + +PyAPI_FUNC(PyObject *) PyException_GetArgs(PyObject *); +PyAPI_FUNC(void) PyException_SetArgs(PyObject *, PyObject *); + /* */ #define PyExceptionClass_Check(x) \ diff --git a/Lib/test/test_capi/test_misc.py b/Lib/test/test_capi/test_misc.py index 03e22d7a2d3..7612cddb1f6 100644 --- a/Lib/test/test_capi/test_misc.py +++ b/Lib/test/test_capi/test_misc.py @@ -1553,5 +1553,44 @@ class Test_Pep523API(unittest.TestCase): self.do_test(func2) +class Test_ErrSetAndRestore(unittest.TestCase): + + def test_err_set_raised(self): + with self.assertRaises(ValueError): + _testcapi.err_set_raised(ValueError()) + v = ValueError() + try: + _testcapi.err_set_raised(v) + except ValueError as ex: + self.assertIs(v, ex) + + def test_err_restore(self): + with self.assertRaises(ValueError): + _testcapi.err_restore(ValueError) + with self.assertRaises(ValueError): + _testcapi.err_restore(ValueError, 1) + with self.assertRaises(ValueError): + _testcapi.err_restore(ValueError, 1, None) + with self.assertRaises(ValueError): + _testcapi.err_restore(ValueError, ValueError()) + try: + _testcapi.err_restore(KeyError, "hi") + except KeyError as k: + self.assertEqual("hi", k.args[0]) + try: + 1/0 + except Exception as e: + tb = e.__traceback__ + with self.assertRaises(ValueError): + _testcapi.err_restore(ValueError, 1, tb) + with self.assertRaises(TypeError): + _testcapi.err_restore(ValueError, 1, 0) + try: + _testcapi.err_restore(ValueError, 1, tb) + except ValueError as v: + self.assertEqual(1, v.args[0]) + self.assertIs(tb, v.__traceback__.tb_next) + + if __name__ == "__main__": unittest.main() diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py index f629321458d..4ae71e431c5 100644 --- a/Lib/test/test_exceptions.py +++ b/Lib/test/test_exceptions.py @@ -347,6 +347,7 @@ class ExceptionTests(unittest.TestCase): _testcapi.raise_exception(BadException, 0) except RuntimeError as err: exc, err, tb = sys.exc_info() + tb = tb.tb_next co = tb.tb_frame.f_code self.assertEqual(co.co_name, "__init__") self.assertTrue(co.co_filename.endswith('test_exceptions.py')) @@ -1415,8 +1416,8 @@ class ExceptionTests(unittest.TestCase): @cpython_only def test_recursion_normalizing_infinite_exception(self): # Issue #30697. Test that a RecursionError is raised when - # PyErr_NormalizeException() maximum recursion depth has been - # exceeded. + # maximum recursion depth has been exceeded when creating + # an exception code = """if 1: import _testcapi try: @@ -1426,8 +1427,7 @@ class ExceptionTests(unittest.TestCase): """ rc, out, err = script_helper.assert_python_failure("-c", code) self.assertEqual(rc, 1) - self.assertIn(b'RecursionError: maximum recursion depth exceeded ' - b'while normalizing an exception', err) + self.assertIn(b'RecursionError: maximum recursion depth exceeded', err) self.assertIn(b'Done.', out) diff --git a/Lib/test/test_stable_abi_ctypes.py b/Lib/test/test_stable_abi_ctypes.py index 67c653428a6..e77c1c84098 100644 --- a/Lib/test/test_stable_abi_ctypes.py +++ b/Lib/test/test_stable_abi_ctypes.py @@ -172,6 +172,7 @@ SYMBOL_NAMES = ( "PyErr_FormatV", "PyErr_GetExcInfo", "PyErr_GetHandledException", + "PyErr_GetRaisedException", "PyErr_GivenExceptionMatches", "PyErr_NewException", "PyErr_NewExceptionWithDoc", @@ -195,6 +196,7 @@ SYMBOL_NAMES = ( "PyErr_SetInterruptEx", "PyErr_SetNone", "PyErr_SetObject", + "PyErr_SetRaisedException", "PyErr_SetString", "PyErr_SyntaxLocation", "PyErr_SyntaxLocationEx", @@ -292,9 +294,11 @@ SYMBOL_NAMES = ( "PyExc_Warning", "PyExc_ZeroDivisionError", "PyExceptionClass_Name", + "PyException_GetArgs", "PyException_GetCause", "PyException_GetContext", "PyException_GetTraceback", + "PyException_SetArgs", "PyException_SetCause", "PyException_SetContext", "PyException_SetTraceback", diff --git a/Misc/NEWS.d/next/C API/2023-02-06-16-14-30.gh-issue-101578.PW5fA9.rst b/Misc/NEWS.d/next/C API/2023-02-06-16-14-30.gh-issue-101578.PW5fA9.rst new file mode 100644 index 00000000000..fc694f6e051 --- /dev/null +++ b/Misc/NEWS.d/next/C API/2023-02-06-16-14-30.gh-issue-101578.PW5fA9.rst @@ -0,0 +1,13 @@ +Add new C-API functions for saving and restoring the current exception: +``PyErr_GetRaisedException`` and ``PyErr_SetRaisedException``. +These functions take and return a single exception rather than +the triple of ``PyErr_Fetch`` and ``PyErr_Restore``. +This is less error prone and a bit more efficient. + +The three arguments forms of saving and restoring the +current exception: ``PyErr_Fetch`` and ``PyErr_Restore`` +are deprecated. + +Also add ``PyException_GetArgs`` and ``PyException_SetArgs`` +as convenience functions to help dealing with +exceptions in the C API. diff --git a/Misc/stable_abi.toml b/Misc/stable_abi.toml index c716f403d63..21ff9616133 100644 --- a/Misc/stable_abi.toml +++ b/Misc/stable_abi.toml @@ -2333,6 +2333,15 @@ added = '3.12' [function.PyVectorcall_Call] added = '3.12' +[function.PyErr_GetRaisedException] + added = '3.12' +[function.PyErr_SetRaisedException] + added = '3.12' +[function.PyException_GetArgs] + added = '3.12' +[function.PyException_SetArgs] + added = '3.12' + [typedef.vectorcallfunc] added = '3.12' [function.PyObject_Vectorcall] diff --git a/Modules/_testcapi/heaptype.c b/Modules/_testcapi/heaptype.c index bf80fd64d80..39639f7ed04 100644 --- a/Modules/_testcapi/heaptype.c +++ b/Modules/_testcapi/heaptype.c @@ -116,10 +116,10 @@ test_from_spec_invalid_metatype_inheritance(PyObject *self, PyObject *Py_UNUSED( PyObject *bases = NULL; PyObject *new = NULL; PyObject *meta_error_string = NULL; - PyObject *exc_type = NULL; - PyObject *exc_value = NULL; - PyObject *exc_traceback = NULL; + PyObject *exc = NULL; PyObject *result = NULL; + PyObject *message = NULL; + PyObject *args = NULL; metaclass_a = PyType_FromSpecWithBases(&MinimalMetaclass_spec, (PyObject*)&PyType_Type); if (metaclass_a == NULL) { @@ -156,13 +156,19 @@ test_from_spec_invalid_metatype_inheritance(PyObject *self, PyObject *Py_UNUSED( // Assert that the correct exception was raised if (PyErr_ExceptionMatches(PyExc_TypeError)) { - PyErr_Fetch(&exc_type, &exc_value, &exc_traceback); - + exc = PyErr_GetRaisedException(); + args = PyException_GetArgs(exc); + if (!PyTuple_Check(args) || PyTuple_Size(args) != 1) { + PyErr_SetString(PyExc_AssertionError, + "TypeError args are not a one-tuple"); + goto finally; + } + message = Py_NewRef(PyTuple_GET_ITEM(args, 0)); meta_error_string = PyUnicode_FromString("metaclass conflict:"); if (meta_error_string == NULL) { goto finally; } - int res = PyUnicode_Contains(exc_value, meta_error_string); + int res = PyUnicode_Contains(message, meta_error_string); if (res < 0) { goto finally; } @@ -179,11 +185,11 @@ finally: Py_XDECREF(bases); Py_XDECREF(new); Py_XDECREF(meta_error_string); - Py_XDECREF(exc_type); - Py_XDECREF(exc_value); - Py_XDECREF(exc_traceback); + Py_XDECREF(exc); + Py_XDECREF(message); Py_XDECREF(class_a); Py_XDECREF(class_b); + Py_XDECREF(args); return result; } diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c index 8b2ce1a2cfd..3c411fa0d76 100644 --- a/Modules/_testcapimodule.c +++ b/Modules/_testcapimodule.c @@ -3470,6 +3470,41 @@ function_set_kw_defaults(PyObject *self, PyObject *args) Py_RETURN_NONE; } +static PyObject * +err_set_raised(PyObject *self, PyObject *exc) +{ + Py_INCREF(exc); + PyErr_SetRaisedException(exc); + assert(PyErr_Occurred()); + return NULL; +} + +static PyObject * +err_restore(PyObject *self, PyObject *args) { + PyObject *type = NULL, *value = NULL, *traceback = NULL; + switch(PyTuple_Size(args)) { + case 3: + traceback = PyTuple_GetItem(args, 2); + Py_INCREF(traceback); + /* fall through */ + case 2: + value = PyTuple_GetItem(args, 1); + Py_INCREF(value); + /* fall through */ + case 1: + type = PyTuple_GetItem(args, 0); + Py_INCREF(type); + break; + default: + PyErr_SetString(PyExc_TypeError, + "wrong number of arguments"); + return NULL; + } + PyErr_Restore(type, value, traceback); + assert(PyErr_Occurred()); + return NULL; +} + static PyObject *test_buildvalue_issue38913(PyObject *, PyObject *); static PyMethodDef TestMethods[] = { @@ -3622,6 +3657,8 @@ static PyMethodDef TestMethods[] = { {"function_set_defaults", function_set_defaults, METH_VARARGS, NULL}, {"function_get_kw_defaults", function_get_kw_defaults, METH_O, NULL}, {"function_set_kw_defaults", function_set_kw_defaults, METH_VARARGS, NULL}, + {"err_set_raised", err_set_raised, METH_O, NULL}, + {"err_restore", err_restore, METH_VARARGS, NULL}, {NULL, NULL} /* sentinel */ }; diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c index 6630faa6f44..5879c5e11fe 100644 --- a/Modules/gcmodule.c +++ b/Modules/gcmodule.c @@ -2082,11 +2082,10 @@ PyGC_Collect(void) n = 0; } else { - PyObject *exc, *value, *tb; gcstate->collecting = 1; - _PyErr_Fetch(tstate, &exc, &value, &tb); + PyObject *exc = _PyErr_GetRaisedException(tstate); n = gc_collect_with_callback(tstate, NUM_GENERATIONS - 1); - _PyErr_Restore(tstate, exc, value, tb); + _PyErr_SetRaisedException(tstate, exc); gcstate->collecting = 0; } diff --git a/Objects/dictobject.c b/Objects/dictobject.c index b9067213820..fc658ca2f4b 100644 --- a/Objects/dictobject.c +++ b/Objects/dictobject.c @@ -1663,15 +1663,15 @@ PyDict_GetItem(PyObject *op, PyObject *key) #endif /* Preserve the existing exception */ - PyObject *exc_type, *exc_value, *exc_tb; PyObject *value; Py_ssize_t ix; (void)ix; - _PyErr_Fetch(tstate, &exc_type, &exc_value, &exc_tb); + + PyObject *exc = _PyErr_GetRaisedException(tstate); ix = _Py_dict_lookup(mp, key, hash, &value); /* Ignore any exception raised by the lookup */ - _PyErr_Restore(tstate, exc_type, exc_value, exc_tb); + _PyErr_SetRaisedException(tstate, exc); assert(ix >= 0 || value == NULL); diff --git a/Objects/exceptions.c b/Objects/exceptions.c index db6f7d52804..976f84dbf63 100644 --- a/Objects/exceptions.c +++ b/Objects/exceptions.c @@ -8,6 +8,7 @@ #include #include #include "pycore_ceval.h" // _Py_EnterRecursiveCall +#include "pycore_pyerrors.h" // struct _PyErr_SetRaisedException #include "pycore_exceptions.h" // struct _Py_exc_state #include "pycore_initconfig.h" #include "pycore_object.h" @@ -288,13 +289,17 @@ BaseException_set_tb(PyBaseExceptionObject *self, PyObject *tb, void *Py_UNUSED( PyErr_SetString(PyExc_TypeError, "__traceback__ may not be deleted"); return -1; } - else if (!(tb == Py_None || PyTraceBack_Check(tb))) { + if (PyTraceBack_Check(tb)) { + Py_XSETREF(self->traceback, Py_NewRef(tb)); + } + else if (tb == Py_None) { + Py_CLEAR(self->traceback); + } + else { PyErr_SetString(PyExc_TypeError, "__traceback__ must be a traceback or None"); return -1; } - - Py_XSETREF(self->traceback, Py_NewRef(tb)); return 0; } @@ -413,6 +418,20 @@ PyException_SetContext(PyObject *self, PyObject *context) Py_XSETREF(_PyBaseExceptionObject_cast(self)->context, context); } +PyObject * +PyException_GetArgs(PyObject *self) +{ + PyObject *args = _PyBaseExceptionObject_cast(self)->args; + return Py_NewRef(args); +} + +void +PyException_SetArgs(PyObject *self, PyObject *args) +{ + Py_INCREF(args); + Py_XSETREF(_PyBaseExceptionObject_cast(self)->args, args); +} + const char * PyExceptionClass_Name(PyObject *ob) { @@ -3188,20 +3207,19 @@ SimpleExtendsException(PyExc_Exception, ReferenceError, #define MEMERRORS_SAVE 16 +static PyBaseExceptionObject last_resort_memory_error; + static PyObject * -MemoryError_new(PyTypeObject *type, PyObject *args, PyObject *kwds) +get_memory_error(int allow_allocation, PyObject *args, PyObject *kwds) { PyBaseExceptionObject *self; - - /* If this is a subclass of MemoryError, don't use the freelist - * and just return a fresh object */ - if (type != (PyTypeObject *) PyExc_MemoryError) { - return BaseException_new(type, args, kwds); - } - struct _Py_exc_state *state = get_exc_state(); if (state->memerrors_freelist == NULL) { - return BaseException_new(type, args, kwds); + if (!allow_allocation) { + return Py_NewRef(&last_resort_memory_error); + } + PyObject *result = BaseException_new((PyTypeObject *)PyExc_MemoryError, args, kwds); + return result; } /* Fetch object from freelist and revive it */ @@ -3221,6 +3239,35 @@ MemoryError_new(PyTypeObject *type, PyObject *args, PyObject *kwds) return (PyObject *)self; } +static PyBaseExceptionObject last_resort_memory_error; + +static PyObject * +MemoryError_new(PyTypeObject *type, PyObject *args, PyObject *kwds) +{ + /* If this is a subclass of MemoryError, don't use the freelist + * and just return a fresh object */ + if (type != (PyTypeObject *) PyExc_MemoryError) { + return BaseException_new(type, args, kwds); + } + return get_memory_error(1, args, kwds); +} + +PyObject * +_PyErr_NoMemory(PyThreadState *tstate) +{ + if (Py_IS_TYPE(PyExc_MemoryError, NULL)) { + /* PyErr_NoMemory() has been called before PyExc_MemoryError has been + initialized by _PyExc_Init() */ + Py_FatalError("Out of memory and PyExc_MemoryError is not " + "initialized yet"); + } + PyObject *err = get_memory_error(0, NULL, NULL); + if (err != NULL) { + _PyErr_SetRaisedException(tstate, err); + } + return NULL; +} + static void MemoryError_dealloc(PyBaseExceptionObject *self) { @@ -3252,6 +3299,7 @@ preallocate_memerrors(void) /* We create enough MemoryErrors and then decref them, which will fill up the freelist. */ int i; + PyObject *errors[MEMERRORS_SAVE]; for (i = 0; i < MEMERRORS_SAVE; i++) { errors[i] = MemoryError_new((PyTypeObject *) PyExc_MemoryError, @@ -3291,6 +3339,9 @@ static PyTypeObject _PyExc_MemoryError = { }; PyObject *PyExc_MemoryError = (PyObject *) &_PyExc_MemoryError; +static PyBaseExceptionObject last_resort_memory_error = { + _PyObject_IMMORTAL_INIT(&_PyExc_MemoryError) +}; /* * BufferError extends Exception diff --git a/Objects/object.c b/Objects/object.c index e940222c657..7817c04ef5f 100644 --- a/Objects/object.c +++ b/Objects/object.c @@ -2416,10 +2416,10 @@ _Py_Dealloc(PyObject *op) destructor dealloc = type->tp_dealloc; #ifdef Py_DEBUG PyThreadState *tstate = _PyThreadState_GET(); - PyObject *old_exc_type = tstate != NULL ? tstate->curexc_type : NULL; + PyObject *old_exc = tstate != NULL ? tstate->current_exception : NULL; // Keep the old exception type alive to prevent undefined behavior // on (tstate->curexc_type != old_exc_type) below - Py_XINCREF(old_exc_type); + Py_XINCREF(old_exc); // Make sure that type->tp_name remains valid Py_INCREF(type); #endif @@ -2432,12 +2432,12 @@ _Py_Dealloc(PyObject *op) #ifdef Py_DEBUG // gh-89373: The tp_dealloc function must leave the current exception // unchanged. - if (tstate != NULL && tstate->curexc_type != old_exc_type) { + if (tstate != NULL && tstate->current_exception != old_exc) { const char *err; - if (old_exc_type == NULL) { + if (old_exc == NULL) { err = "Deallocator of type '%s' raised an exception"; } - else if (tstate->curexc_type == NULL) { + else if (tstate->current_exception == NULL) { err = "Deallocator of type '%s' cleared the current exception"; } else { @@ -2448,7 +2448,7 @@ _Py_Dealloc(PyObject *op) } _Py_FatalErrorFormat(__func__, err, type->tp_name); } - Py_XDECREF(old_exc_type); + Py_XDECREF(old_exc); Py_DECREF(type); #endif } diff --git a/PC/python3dll.c b/PC/python3dll.c index 931f316bb99..e3008193657 100755 --- a/PC/python3dll.c +++ b/PC/python3dll.c @@ -198,6 +198,7 @@ EXPORT_FUNC(PyErr_Format) EXPORT_FUNC(PyErr_FormatV) EXPORT_FUNC(PyErr_GetExcInfo) EXPORT_FUNC(PyErr_GetHandledException) +EXPORT_FUNC(PyErr_GetRaisedException) EXPORT_FUNC(PyErr_GivenExceptionMatches) EXPORT_FUNC(PyErr_NewException) EXPORT_FUNC(PyErr_NewExceptionWithDoc) @@ -227,6 +228,7 @@ EXPORT_FUNC(PyErr_SetInterrupt) EXPORT_FUNC(PyErr_SetInterruptEx) EXPORT_FUNC(PyErr_SetNone) EXPORT_FUNC(PyErr_SetObject) +EXPORT_FUNC(PyErr_SetRaisedException) EXPORT_FUNC(PyErr_SetString) EXPORT_FUNC(PyErr_SyntaxLocation) EXPORT_FUNC(PyErr_SyntaxLocationEx) @@ -255,9 +257,11 @@ EXPORT_FUNC(PyEval_ReleaseThread) EXPORT_FUNC(PyEval_RestoreThread) EXPORT_FUNC(PyEval_SaveThread) EXPORT_FUNC(PyEval_ThreadsInitialized) +EXPORT_FUNC(PyException_GetArgs) EXPORT_FUNC(PyException_GetCause) EXPORT_FUNC(PyException_GetContext) EXPORT_FUNC(PyException_GetTraceback) +EXPORT_FUNC(PyException_SetArgs) EXPORT_FUNC(PyException_SetCause) EXPORT_FUNC(PyException_SetContext) EXPORT_FUNC(PyException_SetTraceback) diff --git a/Parser/pegen.c b/Parser/pegen.c index d84e06861ed..94dd9de8a43 100644 --- a/Parser/pegen.c +++ b/Parser/pegen.c @@ -643,13 +643,10 @@ _PyPegen_number_token(Parser *p) PyThreadState *tstate = _PyThreadState_GET(); // The only way a ValueError should happen in _this_ code is via // PyLong_FromString hitting a length limit. - if (tstate->curexc_type == PyExc_ValueError && - tstate->curexc_value != NULL) { - PyObject *type, *value, *tb; - // This acts as PyErr_Clear() as we're replacing curexc. - PyErr_Fetch(&type, &value, &tb); - Py_XDECREF(tb); - Py_DECREF(type); + if (tstate->current_exception != NULL && + Py_TYPE(tstate->current_exception) == (PyTypeObject *)PyExc_ValueError + ) { + PyObject *exc = PyErr_GetRaisedException(); /* Intentionally omitting columns to avoid a wall of 1000s of '^'s * on the error message. Nobody is going to overlook their huge * numeric literal once given the line. */ @@ -659,8 +656,8 @@ _PyPegen_number_token(Parser *p) t->end_lineno, -1 /* end_col_offset */, "%S - Consider hexadecimal for huge integer literals " "to avoid decimal conversion limits.", - value); - Py_DECREF(value); + exc); + Py_DECREF(exc); } return NULL; } diff --git a/Python/bytecodes.c b/Python/bytecodes.c index 9633f34212a..1169d8d172d 100644 --- a/Python/bytecodes.c +++ b/Python/bytecodes.c @@ -804,9 +804,7 @@ dummy_func( DECREF_INPUTS(); } else { - PyObject *exc_type = Py_NewRef(Py_TYPE(exc_value)); - PyObject *exc_traceback = PyException_GetTraceback(exc_value); - _PyErr_Restore(tstate, exc_type, Py_NewRef(exc_value), exc_traceback); + _PyErr_SetRaisedException(tstate, Py_NewRef(exc_value)); goto exception_unwind; } } diff --git a/Python/ceval.c b/Python/ceval.c index ecb5bf96555..a91f5baca88 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -2902,13 +2902,13 @@ format_kwargs_error(PyThreadState *tstate, PyObject *func, PyObject *kwargs) } } else if (_PyErr_ExceptionMatches(tstate, PyExc_KeyError)) { - PyObject *exc, *val, *tb; - _PyErr_Fetch(tstate, &exc, &val, &tb); - if (val && PyTuple_Check(val) && PyTuple_GET_SIZE(val) == 1) { + PyObject *exc = _PyErr_GetRaisedException(tstate); + PyObject *args = ((PyBaseExceptionObject *)exc)->args; + if (exc && PyTuple_Check(args) && PyTuple_GET_SIZE(args) == 1) { _PyErr_Clear(tstate); PyObject *funcstr = _PyObject_FunctionStr(func); if (funcstr != NULL) { - PyObject *key = PyTuple_GET_ITEM(val, 0); + PyObject *key = PyTuple_GET_ITEM(args, 0); _PyErr_Format( tstate, PyExc_TypeError, "%U got multiple values for keyword argument '%S'", @@ -2916,11 +2916,9 @@ format_kwargs_error(PyThreadState *tstate, PyObject *func, PyObject *kwargs) Py_DECREF(funcstr); } Py_XDECREF(exc); - Py_XDECREF(val); - Py_XDECREF(tb); } else { - _PyErr_Restore(tstate, exc, val, tb); + _PyErr_SetRaisedException(tstate, exc); } } } diff --git a/Python/errors.c b/Python/errors.c index 05ef62246ec..f573bed3d63 100644 --- a/Python/errors.c +++ b/Python/errors.c @@ -27,54 +27,12 @@ static PyObject * _PyErr_FormatV(PyThreadState *tstate, PyObject *exception, const char *format, va_list vargs); - void -_PyErr_Restore(PyThreadState *tstate, PyObject *type, PyObject *value, - PyObject *traceback) +_PyErr_SetRaisedException(PyThreadState *tstate, PyObject *exc) { - PyObject *oldtype, *oldvalue, *oldtraceback; - - if (traceback != NULL && !PyTraceBack_Check(traceback)) { - /* XXX Should never happen -- fatal error instead? */ - /* Well, it could be None. */ - Py_SETREF(traceback, NULL); - } - - /* Save these in locals to safeguard against recursive - invocation through Py_XDECREF */ - oldtype = tstate->curexc_type; - oldvalue = tstate->curexc_value; - oldtraceback = tstate->curexc_traceback; - - tstate->curexc_type = type; - tstate->curexc_value = value; - tstate->curexc_traceback = traceback; - - Py_XDECREF(oldtype); - Py_XDECREF(oldvalue); - Py_XDECREF(oldtraceback); -} - -void -PyErr_Restore(PyObject *type, PyObject *value, PyObject *traceback) -{ - PyThreadState *tstate = _PyThreadState_GET(); - _PyErr_Restore(tstate, type, value, traceback); -} - - -_PyErr_StackItem * -_PyErr_GetTopmostException(PyThreadState *tstate) -{ - _PyErr_StackItem *exc_info = tstate->exc_info; - assert(exc_info); - - while ((exc_info->exc_value == NULL || exc_info->exc_value == Py_None) && - exc_info->previous_item != NULL) - { - exc_info = exc_info->previous_item; - } - return exc_info; + PyObject *old_exc = tstate->current_exception; + tstate->current_exception = exc; + Py_XDECREF(old_exc); } static PyObject* @@ -103,6 +61,80 @@ _PyErr_CreateException(PyObject *exception_type, PyObject *value) return exc; } +void +_PyErr_Restore(PyThreadState *tstate, PyObject *type, PyObject *value, + PyObject *traceback) +{ + if (type == NULL) { + assert(value == NULL); + assert(traceback == NULL); + _PyErr_SetRaisedException(tstate, NULL); + return; + } + assert(PyExceptionClass_Check(type)); + if (value != NULL && type == (PyObject *)Py_TYPE(value)) { + /* Already normalized */ + assert(((PyBaseExceptionObject *)value)->traceback != Py_None); + } + else { + PyObject *exc = _PyErr_CreateException(type, value); + Py_XDECREF(value); + if (exc == NULL) { + Py_DECREF(type); + Py_XDECREF(traceback); + return; + } + value = exc; + } + assert(PyExceptionInstance_Check(value)); + if (traceback != NULL && !PyTraceBack_Check(traceback)) { + if (traceback == Py_None) { + Py_DECREF(Py_None); + traceback = NULL; + } + else { + PyErr_SetString(PyExc_TypeError, "traceback must be a Traceback or None"); + Py_XDECREF(value); + Py_DECREF(type); + Py_XDECREF(traceback); + return; + } + } + PyObject *old_traceback = ((PyBaseExceptionObject *)value)->traceback; + ((PyBaseExceptionObject *)value)->traceback = traceback; + Py_XDECREF(old_traceback); + _PyErr_SetRaisedException(tstate, value); + Py_DECREF(type); +} + +void +PyErr_Restore(PyObject *type, PyObject *value, PyObject *traceback) +{ + PyThreadState *tstate = _PyThreadState_GET(); + _PyErr_Restore(tstate, type, value, traceback); +} + +void +PyErr_SetRaisedException(PyObject *exc) +{ + PyThreadState *tstate = _PyThreadState_GET(); + _PyErr_SetRaisedException(tstate, exc); +} + +_PyErr_StackItem * +_PyErr_GetTopmostException(PyThreadState *tstate) +{ + _PyErr_StackItem *exc_info = tstate->exc_info; + assert(exc_info); + + while ((exc_info->exc_value == NULL || exc_info->exc_value == Py_None) && + exc_info->previous_item != NULL) + { + exc_info = exc_info->previous_item; + } + return exc_info; +} + void _PyErr_SetObject(PyThreadState *tstate, PyObject *exception, PyObject *value) { @@ -117,30 +149,29 @@ _PyErr_SetObject(PyThreadState *tstate, PyObject *exception, PyObject *value) exception); return; } - Py_XINCREF(value); + /* Normalize the exception */ + if (value == NULL || (PyObject *)Py_TYPE(value) != exception) { + /* We must normalize the value right now */ + PyObject *fixed_value; + + /* Issue #23571: functions must not be called with an + exception set */ + _PyErr_Clear(tstate); + + fixed_value = _PyErr_CreateException(exception, value); + Py_XDECREF(value); + if (fixed_value == NULL) { + return; + } + + value = fixed_value; + } + exc_value = _PyErr_GetTopmostException(tstate)->exc_value; if (exc_value != NULL && exc_value != Py_None) { /* Implicit exception chaining */ Py_INCREF(exc_value); - if (value == NULL || !PyExceptionInstance_Check(value)) { - /* We must normalize the value right now */ - PyObject *fixed_value; - - /* Issue #23571: functions must not be called with an - exception set */ - _PyErr_Clear(tstate); - - fixed_value = _PyErr_CreateException(exception, value); - Py_XDECREF(value); - if (fixed_value == NULL) { - Py_DECREF(exc_value); - return; - } - - value = fixed_value; - } - /* Avoid creating new reference cycles through the context chain, while taking care not to hang on pre-existing ones. @@ -414,17 +445,34 @@ PyErr_NormalizeException(PyObject **exc, PyObject **val, PyObject **tb) } +PyObject * +_PyErr_GetRaisedException(PyThreadState *tstate) { + PyObject *exc = tstate->current_exception; + tstate->current_exception = NULL; + return exc; +} + +PyObject * +PyErr_GetRaisedException(void) +{ + PyThreadState *tstate = _PyThreadState_GET(); + return _PyErr_GetRaisedException(tstate); +} + void _PyErr_Fetch(PyThreadState *tstate, PyObject **p_type, PyObject **p_value, PyObject **p_traceback) { - *p_type = tstate->curexc_type; - *p_value = tstate->curexc_value; - *p_traceback = tstate->curexc_traceback; - - tstate->curexc_type = NULL; - tstate->curexc_value = NULL; - tstate->curexc_traceback = NULL; + PyObject *exc = _PyErr_GetRaisedException(tstate); + *p_value = exc; + if (exc == NULL) { + *p_type = NULL; + *p_traceback = NULL; + } + else { + *p_type = Py_NewRef(Py_TYPE(exc)); + *p_traceback = Py_XNewRef(((PyBaseExceptionObject *)exc)->traceback); + } } @@ -597,6 +645,28 @@ _PyErr_ChainExceptions(PyObject *typ, PyObject *val, PyObject *tb) } } +/* Like PyErr_SetRaisedException(), but if an exception is already set, + set the context associated with it. + + The caller is responsible for ensuring that this call won't create + any cycles in the exception context chain. */ +void +_PyErr_ChainExceptions1(PyObject *exc) +{ + if (exc == NULL) { + return; + } + PyThreadState *tstate = _PyThreadState_GET(); + if (_PyErr_Occurred(tstate)) { + PyObject *exc2 = _PyErr_GetRaisedException(tstate); + PyException_SetContext(exc2, exc); + _PyErr_SetRaisedException(tstate, exc2); + } + else { + _PyErr_SetRaisedException(tstate, exc); + } +} + /* Set the currently set exception's context to the given exception. If the provided exc_info is NULL, then the current Python thread state's @@ -706,19 +776,6 @@ PyErr_BadArgument(void) return 0; } -PyObject * -_PyErr_NoMemory(PyThreadState *tstate) -{ - if (Py_IS_TYPE(PyExc_MemoryError, NULL)) { - /* PyErr_NoMemory() has been called before PyExc_MemoryError has been - initialized by _PyExc_Init() */ - Py_FatalError("Out of memory and PyExc_MemoryError is not " - "initialized yet"); - } - _PyErr_SetNone(tstate, PyExc_MemoryError); - return NULL; -} - PyObject * PyErr_NoMemory(void) { diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h index f38286441be..09eb6893ebf 100644 --- a/Python/generated_cases.c.h +++ b/Python/generated_cases.c.h @@ -1036,9 +1036,7 @@ Py_DECREF(exc_value); } else { - PyObject *exc_type = Py_NewRef(Py_TYPE(exc_value)); - PyObject *exc_traceback = PyException_GetTraceback(exc_value); - _PyErr_Restore(tstate, exc_type, Py_NewRef(exc_value), exc_traceback); + _PyErr_SetRaisedException(tstate, Py_NewRef(exc_value)); goto exception_unwind; } STACK_SHRINK(2); diff --git a/Python/import.c b/Python/import.c index da6c15c5fd4..1318c09d9b3 100644 --- a/Python/import.c +++ b/Python/import.c @@ -1592,6 +1592,13 @@ remove_importlib_frames(PyThreadState *tstate) Py_DECREF(code); tb = next; } + assert(PyExceptionInstance_Check(value)); + assert((PyObject *)Py_TYPE(value) == exception); + if (base_tb == NULL) { + base_tb = Py_None; + Py_INCREF(Py_None); + } + PyException_SetTraceback(value, base_tb); done: _PyErr_Restore(tstate, exception, value, base_tb); } diff --git a/Python/initconfig.c b/Python/initconfig.c index d7b2dc4a297..deec805a6b1 100644 --- a/Python/initconfig.c +++ b/Python/initconfig.c @@ -3143,8 +3143,7 @@ init_dump_ascii_wstr(const wchar_t *str) void _Py_DumpPathConfig(PyThreadState *tstate) { - PyObject *exc_type, *exc_value, *exc_tb; - _PyErr_Fetch(tstate, &exc_type, &exc_value, &exc_tb); + PyObject *exc = _PyErr_GetRaisedException(tstate); PySys_WriteStderr("Python path configuration:\n"); @@ -3202,5 +3201,5 @@ _Py_DumpPathConfig(PyThreadState *tstate) PySys_WriteStderr(" ]\n"); } - _PyErr_Restore(tstate, exc_type, exc_value, exc_tb); + _PyErr_SetRaisedException(tstate, exc); } diff --git a/Python/pystate.c b/Python/pystate.c index ed8c2e212a5..1261092d143 100644 --- a/Python/pystate.c +++ b/Python/pystate.c @@ -1375,9 +1375,7 @@ PyThreadState_Clear(PyThreadState *tstate) Py_CLEAR(tstate->dict); Py_CLEAR(tstate->async_exc); - Py_CLEAR(tstate->curexc_type); - Py_CLEAR(tstate->curexc_value); - Py_CLEAR(tstate->curexc_traceback); + Py_CLEAR(tstate->current_exception); Py_CLEAR(tstate->exc_state.exc_value); diff --git a/Python/pythonrun.c b/Python/pythonrun.c index 35292b6478a..6a4d5937686 100644 --- a/Python/pythonrun.c +++ b/Python/pythonrun.c @@ -748,13 +748,10 @@ _Py_HandleSystemExit(int *exitcode_p) } done: - /* Restore and clear the exception info, in order to properly decref - * the exception, value, and traceback. If we just exit instead, - * these leak, which confuses PYTHONDUMPREFS output, and may prevent - * some finalizers from running. - */ - PyErr_Restore(exception, value, tb); - PyErr_Clear(); + /* Cleanup the exception */ + Py_CLEAR(exception); + Py_CLEAR(value); + Py_CLEAR(tb); *exitcode_p = exitcode; return 1; } diff --git a/Python/sysmodule.c b/Python/sysmodule.c index f9f766a94d1..6e81ef92b67 100644 --- a/Python/sysmodule.c +++ b/Python/sysmodule.c @@ -66,12 +66,11 @@ _PySys_GetAttr(PyThreadState *tstate, PyObject *name) if (sd == NULL) { return NULL; } - PyObject *exc_type, *exc_value, *exc_tb; - _PyErr_Fetch(tstate, &exc_type, &exc_value, &exc_tb); + PyObject *exc = _PyErr_GetRaisedException(tstate); /* XXX Suppress a new exception if it was raised and restore * the old one. */ PyObject *value = _PyDict_GetItemWithError(sd, name); - _PyErr_Restore(tstate, exc_type, exc_value, exc_tb); + _PyErr_SetRaisedException(tstate, exc); return value; } @@ -3704,11 +3703,10 @@ static void sys_format(PyObject *key, FILE *fp, const char *format, va_list va) { PyObject *file, *message; - PyObject *error_type, *error_value, *error_traceback; const char *utf8; PyThreadState *tstate = _PyThreadState_GET(); - _PyErr_Fetch(tstate, &error_type, &error_value, &error_traceback); + PyObject *error = _PyErr_GetRaisedException(tstate); file = _PySys_GetAttr(tstate, key); message = PyUnicode_FromFormatV(format, va); if (message != NULL) { @@ -3720,7 +3718,7 @@ sys_format(PyObject *key, FILE *fp, const char *format, va_list va) } Py_DECREF(message); } - _PyErr_Restore(tstate, error_type, error_value, error_traceback); + _PyErr_SetRaisedException(tstate, error); } void diff --git a/Python/traceback.c b/Python/traceback.c index da26c9b260a..31b85e77575 100644 --- a/Python/traceback.c +++ b/Python/traceback.c @@ -249,6 +249,8 @@ PyTraceBack_Here(PyFrameObject *frame) _PyErr_ChainExceptions(exc, val, tb); return -1; } + assert(PyExceptionInstance_Check(val)); + PyException_SetTraceback(val, newtb); PyErr_Restore(exc, val, newtb); Py_XDECREF(tb); return 0; @@ -260,13 +262,12 @@ void _PyTraceback_Add(const char *funcname, const char *filename, int lineno) PyObject *globals; PyCodeObject *code; PyFrameObject *frame; - PyObject *exc, *val, *tb; PyThreadState *tstate = _PyThreadState_GET(); /* Save and clear the current exception. Python functions must not be called with an exception set. Calling Python functions happens when the codec of the filesystem encoding is implemented in pure Python. */ - _PyErr_Fetch(tstate, &exc, &val, &tb); + PyObject *exc = _PyErr_GetRaisedException(tstate); globals = PyDict_New(); if (!globals) @@ -283,13 +284,13 @@ void _PyTraceback_Add(const char *funcname, const char *filename, int lineno) goto error; frame->f_lineno = lineno; - _PyErr_Restore(tstate, exc, val, tb); + _PyErr_SetRaisedException(tstate, exc); PyTraceBack_Here(frame); Py_DECREF(frame); return; error: - _PyErr_ChainExceptions(exc, val, tb); + _PyErr_ChainExceptions1(exc); } static PyObject *