/*

* New exceptions.c written in Iceland by Richard Jones and Georg Brandl.

*

* Thanks go to Tim Peters and Michael Hudson for debugging.

*/

#define PY_SSIZE_T_CLEAN

#include <Python.h>

#include <stdbool.h>

#include "pycore_exceptions.h" // struct _Py_exc_state

#include "pycore_initconfig.h"

#include "pycore_object.h"

#include "structmember.h" // PyMemberDef

#include "osdefs.h" // SEP

/* Compatibility aliases */

PyObject *PyExc_EnvironmentError = NULL;

PyObject *PyExc_IOError = NULL;

#ifdef MS_WINDOWS

PyObject *PyExc_WindowsError = NULL;

#endif

static struct _Py_exc_state*

get_exc_state(void)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

return &interp->exc_state;

}

/* NOTE: If the exception class hierarchy changes, don't forget to update

* Lib/test/exception_hierarchy.txt

*/

/*

* BaseException

*/

static PyObject *

BaseException_new(PyTypeObject *type, PyObject *args, PyObject *kwds)

{

PyBaseExceptionObject *self;

self = (PyBaseExceptionObject *)type->tp_alloc(type, 0);

if (!self)

return NULL;

/* the dict is created on the fly in PyObject_GenericSetAttr */

self->dict = NULL;

self->note = NULL;

self->traceback = self->cause = self->context = NULL;

self->suppress_context = 0;

if (args) {

self->args = args;

Py_INCREF(args);

return (PyObject *)self;

}

self->args = PyTuple_New(0);

if (!self->args) {

Py_DECREF(self);

return NULL;

}

return (PyObject *)self;

}

static int

BaseException_init(PyBaseExceptionObject *self, PyObject *args, PyObject *kwds)

{

if (!_PyArg_NoKeywords(Py_TYPE(self)->tp_name, kwds))

return -1;

Py_INCREF(args);

Py_XSETREF(self->args, args);

return 0;

}

static int

BaseException_clear(PyBaseExceptionObject *self)

{

Py_CLEAR(self->dict);

Py_CLEAR(self->args);

Py_CLEAR(self->note);

Py_CLEAR(self->traceback);

Py_CLEAR(self->cause);

Py_CLEAR(self->context);

return 0;

}

static void

BaseException_dealloc(PyBaseExceptionObject *self)

{

PyObject_GC_UnTrack(self);

// bpo-44348: The trashcan mechanism prevents stack overflow when deleting

// long chains of exceptions. For example, exceptions can be chained

// through the __context__ attributes or the __traceback__ attribute.

Py_TRASHCAN_BEGIN(self, BaseException_dealloc)

BaseException_clear(self);

Py_TYPE(self)->tp_free((PyObject *)self);

Py_TRASHCAN_END

}

static int

BaseException_traverse(PyBaseExceptionObject *self, visitproc visit, void *arg)

{

Py_VISIT(self->dict);

Py_VISIT(self->args);

Py_VISIT(self->note);

Py_VISIT(self->traceback);

Py_VISIT(self->cause);

Py_VISIT(self->context);

return 0;

}

static PyObject *

BaseException_str(PyBaseExceptionObject *self)

{

switch (PyTuple_GET_SIZE(self->args)) {

case 0:

return PyUnicode_FromString("");

case 1:

return PyObject_Str(PyTuple_GET_ITEM(self->args, 0));

default:

return PyObject_Str(self->args);

}

}

static PyObject *

BaseException_repr(PyBaseExceptionObject *self)

{

const char *name = _PyType_Name(Py_TYPE(self));

if (PyTuple_GET_SIZE(self->args) == 1)

return PyUnicode_FromFormat("%s(%R)", name,

PyTuple_GET_ITEM(self->args, 0));

else

return PyUnicode_FromFormat("%s%R", name, self->args);

}

/* Pickling support */

static PyObject *

BaseException_reduce(PyBaseExceptionObject *self, PyObject *Py_UNUSED(ignored))

{

if (self->args && self->dict)

return PyTuple_Pack(3, Py_TYPE(self), self->args, self->dict);

else

return PyTuple_Pack(2, Py_TYPE(self), self->args);

}

/*

* Needed for backward compatibility, since exceptions used to store

* all their attributes in the __dict__. Code is taken from cPickle's

* load_build function.

*/

static PyObject *

BaseException_setstate(PyObject *self, PyObject *state)

{

PyObject *d_key, *d_value;

Py_ssize_t i = 0;

if (state != Py_None) {

if (!PyDict_Check(state)) {

PyErr_SetString(PyExc_TypeError, "state is not a dictionary");

return NULL;

}

while (PyDict_Next(state, &i, &d_key, &d_value)) {

if (PyObject_SetAttr(self, d_key, d_value) < 0)

return NULL;

}

}

Py_RETURN_NONE;

}

static PyObject *

BaseException_with_traceback(PyObject *self, PyObject *tb) {

if (PyException_SetTraceback(self, tb))

return NULL;

Py_INCREF(self);

return self;

}

PyDoc_STRVAR(with_traceback_doc,

"Exception.with_traceback(tb) --\n\

set self.__traceback__ to tb and return self.");

static PyMethodDef BaseException_methods[] = {

{"__reduce__", (PyCFunction)BaseException_reduce, METH_NOARGS },

{"__setstate__", (PyCFunction)BaseException_setstate, METH_O },

{"with_traceback", (PyCFunction)BaseException_with_traceback, METH_O,

with_traceback_doc},

{NULL, NULL, 0, NULL},

};

static PyObject *

BaseException_get_args(PyBaseExceptionObject *self, void *Py_UNUSED(ignored))

{

if (self->args == NULL) {

Py_RETURN_NONE;

}

Py_INCREF(self->args);

return self->args;

}

static int

BaseException_set_args(PyBaseExceptionObject *self, PyObject *val, void *Py_UNUSED(ignored))

{

PyObject *seq;

if (val == NULL) {

PyErr_SetString(PyExc_TypeError, "args may not be deleted");

return -1;

}

seq = PySequence_Tuple(val);

if (!seq)

return -1;

Py_XSETREF(self->args, seq);

return 0;

}

static PyObject *

BaseException_get_note(PyBaseExceptionObject *self, void *Py_UNUSED(ignored))

{

if (self->note == NULL) {

Py_RETURN_NONE;

}

return Py_NewRef(self->note);

}

static int

BaseException_set_note(PyBaseExceptionObject *self, PyObject *note,

void *Py_UNUSED(ignored))

{

if (note == NULL) {

PyErr_SetString(PyExc_TypeError, "__note__ may not be deleted");

return -1;

}

else if (note != Py_None && !PyUnicode_CheckExact(note)) {

PyErr_SetString(PyExc_TypeError, "__note__ must be a string or None");

return -1;

}

Py_INCREF(note);

Py_XSETREF(self->note, note);

return 0;

}

static PyObject *

BaseException_get_tb(PyBaseExceptionObject *self, void *Py_UNUSED(ignored))

{

if (self->traceback == NULL) {

Py_RETURN_NONE;

}

Py_INCREF(self->traceback);

return self->traceback;

}

static int

BaseException_set_tb(PyBaseExceptionObject *self, PyObject *tb, void *Py_UNUSED(ignored))

{

if (tb == NULL) {

PyErr_SetString(PyExc_TypeError, "__traceback__ may not be deleted");

return -1;

}

else if (!(tb == Py_None || PyTraceBack_Check(tb))) {

PyErr_SetString(PyExc_TypeError,

"__traceback__ must be a traceback or None");

return -1;

}

Py_INCREF(tb);

Py_XSETREF(self->traceback, tb);

return 0;

}

static PyObject *

BaseException_get_context(PyObject *self, void *Py_UNUSED(ignored))

{

PyObject *res = PyException_GetContext(self);

if (res)

return res; /* new reference already returned above */

Py_RETURN_NONE;

}

static int

BaseException_set_context(PyObject *self, PyObject *arg, void *Py_UNUSED(ignored))

{

if (arg == NULL) {

PyErr_SetString(PyExc_TypeError, "__context__ may not be deleted");

return -1;

} else if (arg == Py_None) {

arg = NULL;

} else if (!PyExceptionInstance_Check(arg)) {

PyErr_SetString(PyExc_TypeError, "exception context must be None "

"or derive from BaseException");

return -1;

} else {

/* PyException_SetContext steals this reference */

Py_INCREF(arg);

}

PyException_SetContext(self, arg);

return 0;

}

static PyObject *

BaseException_get_cause(PyObject *self, void *Py_UNUSED(ignored))

{

PyObject *res = PyException_GetCause(self);

if (res)

return res; /* new reference already returned above */

Py_RETURN_NONE;

}

static int

BaseException_set_cause(PyObject *self, PyObject *arg, void *Py_UNUSED(ignored))

{

if (arg == NULL) {

PyErr_SetString(PyExc_TypeError, "__cause__ may not be deleted");

return -1;

} else if (arg == Py_None) {

arg = NULL;

} else if (!PyExceptionInstance_Check(arg)) {

PyErr_SetString(PyExc_TypeError, "exception cause must be None "

"or derive from BaseException");

return -1;

} else {

/* PyException_SetCause steals this reference */

Py_INCREF(arg);

}

PyException_SetCause(self, arg);

return 0;

}

static PyGetSetDef BaseException_getset[] = {

{"__dict__", PyObject_GenericGetDict, PyObject_GenericSetDict},

{"args", (getter)BaseException_get_args, (setter)BaseException_set_args},

{"__note__", (getter)BaseException_get_note, (setter)BaseException_set_note},

{"__traceback__", (getter)BaseException_get_tb, (setter)BaseException_set_tb},

{"__context__", BaseException_get_context,

BaseException_set_context, PyDoc_STR("exception context")},

{"__cause__", BaseException_get_cause,

BaseException_set_cause, PyDoc_STR("exception cause")},

{NULL},

};

static inline PyBaseExceptionObject*

_PyBaseExceptionObject_cast(PyObject *exc)

{

assert(PyExceptionInstance_Check(exc));

return (PyBaseExceptionObject *)exc;

}

PyObject *

PyException_GetTraceback(PyObject *self)

{

PyBaseExceptionObject *base_self = _PyBaseExceptionObject_cast(self);

Py_XINCREF(base_self->traceback);

return base_self->traceback;

}

int

PyException_SetTraceback(PyObject *self, PyObject *tb)

{

return BaseException_set_tb(_PyBaseExceptionObject_cast(self), tb, NULL);

}

PyObject *

PyException_GetCause(PyObject *self)

{

PyObject *cause = _PyBaseExceptionObject_cast(self)->cause;

Py_XINCREF(cause);

return cause;

}

/* Steals a reference to cause */

void

PyException_SetCause(PyObject *self, PyObject *cause)

{

PyBaseExceptionObject *base_self = _PyBaseExceptionObject_cast(self);

base_self->suppress_context = 1;

Py_XSETREF(base_self->cause, cause);

}

PyObject *

PyException_GetContext(PyObject *self)

{

PyObject *context = _PyBaseExceptionObject_cast(self)->context;

Py_XINCREF(context);

return context;

}

/* Steals a reference to context */

void

PyException_SetContext(PyObject *self, PyObject *context)

{

Py_XSETREF(_PyBaseExceptionObject_cast(self)->context, context);

}

const char *

PyExceptionClass_Name(PyObject *ob)

{

assert(PyExceptionClass_Check(ob));

return ((PyTypeObject*)ob)->tp_name;

}

static struct PyMemberDef BaseException_members[] = {

{"__suppress_context__", T_BOOL,

offsetof(PyBaseExceptionObject, suppress_context)},

{NULL}

};

static PyTypeObject _PyExc_BaseException = {

PyVarObject_HEAD_INIT(NULL, 0)

"BaseException", /*tp_name*/

sizeof(PyBaseExceptionObject), /*tp_basicsize*/

0, /*tp_itemsize*/

(destructor)BaseException_dealloc, /*tp_dealloc*/

0, /*tp_vectorcall_offset*/

0, /*tp_getattr*/

0, /*tp_setattr*/

0, /*tp_as_async*/

(reprfunc)BaseException_repr, /*tp_repr*/

0, /*tp_as_number*/

0, /*tp_as_sequence*/

0, /*tp_as_mapping*/

0, /*tp_hash */

0, /*tp_call*/

(reprfunc)BaseException_str, /*tp_str*/

PyObject_GenericGetAttr, /*tp_getattro*/

PyObject_GenericSetAttr, /*tp_setattro*/

0, /*tp_as_buffer*/

Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC |

Py_TPFLAGS_BASE_EXC_SUBCLASS, /*tp_flags*/

PyDoc_STR("Common base class for all exceptions"), /* tp_doc */

(traverseproc)BaseException_traverse, /* tp_traverse */

(inquiry)BaseException_clear, /* tp_clear */

0, /* tp_richcompare */

0, /* tp_weaklistoffset */

0, /* tp_iter */

0, /* tp_iternext */

BaseException_methods, /* tp_methods */

BaseException_members, /* tp_members */

BaseException_getset, /* tp_getset */

0, /* tp_base */

0, /* tp_dict */

0, /* tp_descr_get */

0, /* tp_descr_set */

offsetof(PyBaseExceptionObject, dict), /* tp_dictoffset */

(initproc)BaseException_init, /* tp_init */

0, /* tp_alloc */

BaseException_new, /* tp_new */

};

/* the CPython API expects exceptions to be (PyObject *) - both a hold-over

from the previous implementation and also allowing Python objects to be used

in the API */

PyObject *PyExc_BaseException = (PyObject *)&_PyExc_BaseException;

/* note these macros omit the last semicolon so the macro invocation may

* include it and not look strange.

*/

#define SimpleExtendsException(EXCBASE, EXCNAME, EXCDOC) \

static PyTypeObject _PyExc_ ## EXCNAME = { \

PyVarObject_HEAD_INIT(NULL, 0) \

# EXCNAME, \

sizeof(PyBaseExceptionObject), \

0, (destructor)BaseException_dealloc, 0, 0, 0, 0, 0, 0, 0, \

0, 0, 0, 0, 0, 0, 0, \

Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC, \

PyDoc_STR(EXCDOC), (traverseproc)BaseException_traverse, \

(inquiry)BaseException_clear, 0, 0, 0, 0, 0, 0, 0, &_ ## EXCBASE, \

0, 0, 0, offsetof(PyBaseExceptionObject, dict), \

(initproc)BaseException_init, 0, BaseException_new,\

}; \

PyObject *PyExc_ ## EXCNAME = (PyObject *)&_PyExc_ ## EXCNAME

#define MiddlingExtendsException(EXCBASE, EXCNAME, EXCSTORE, EXCDOC) \

static PyTypeObject _PyExc_ ## EXCNAME = { \

PyVarObject_HEAD_INIT(NULL, 0) \

# EXCNAME, \

sizeof(Py ## EXCSTORE ## Object), \

0, (destructor)EXCSTORE ## _dealloc, 0, 0, 0, 0, 0, 0, 0, 0, 0, \

0, 0, 0, 0, 0, \

Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC, \

PyDoc_STR(EXCDOC), (traverseproc)EXCSTORE ## _traverse, \

(inquiry)EXCSTORE ## _clear, 0, 0, 0, 0, 0, 0, 0, &_ ## EXCBASE, \

0, 0, 0, offsetof(Py ## EXCSTORE ## Object, dict), \

(initproc)EXCSTORE ## _init, 0, 0, \

}; \

PyObject *PyExc_ ## EXCNAME = (PyObject *)&_PyExc_ ## EXCNAME

#define ComplexExtendsException(EXCBASE, EXCNAME, EXCSTORE, EXCNEW, \

EXCMETHODS, EXCMEMBERS, EXCGETSET, \

EXCSTR, EXCDOC) \

static PyTypeObject _PyExc_ ## EXCNAME = { \

PyVarObject_HEAD_INIT(NULL, 0) \

# EXCNAME, \

sizeof(Py ## EXCSTORE ## Object), 0, \

(destructor)EXCSTORE ## _dealloc, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \

(reprfunc)EXCSTR, 0, 0, 0, \

Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC, \

PyDoc_STR(EXCDOC), (traverseproc)EXCSTORE ## _traverse, \

(inquiry)EXCSTORE ## _clear, 0, 0, 0, 0, EXCMETHODS, \

EXCMEMBERS, EXCGETSET, &_ ## EXCBASE, \

0, 0, 0, offsetof(Py ## EXCSTORE ## Object, dict), \

(initproc)EXCSTORE ## _init, 0, EXCNEW,\

}; \

PyObject *PyExc_ ## EXCNAME = (PyObject *)&_PyExc_ ## EXCNAME

/*

* Exception extends BaseException

*/

SimpleExtendsException(PyExc_BaseException, Exception,

"Common base class for all non-exit exceptions.");

/*

* TypeError extends Exception

*/

SimpleExtendsException(PyExc_Exception, TypeError,

"Inappropriate argument type.");

/*

* StopAsyncIteration extends Exception

*/

SimpleExtendsException(PyExc_Exception, StopAsyncIteration,

"Signal the end from iterator.__anext__().");

/*

* StopIteration extends Exception

*/

static PyMemberDef StopIteration_members[] = {

{"value", T_OBJECT, offsetof(PyStopIterationObject, value), 0,

PyDoc_STR("generator return value")},

{NULL} /* Sentinel */

};

static int

StopIteration_init(PyStopIterationObject *self, PyObject *args, PyObject *kwds)

{

Py_ssize_t size = PyTuple_GET_SIZE(args);

PyObject *value;

if (BaseException_init((PyBaseExceptionObject *)self, args, kwds) == -1)

return -1;

Py_CLEAR(self->value);

if (size > 0)

value = PyTuple_GET_ITEM(args, 0);

else

value = Py_None;

Py_INCREF(value);

self->value = value;

return 0;

}

static int

StopIteration_clear(PyStopIterationObject *self)

{

Py_CLEAR(self->value);

return BaseException_clear((PyBaseExceptionObject *)self);

}

static void

StopIteration_dealloc(PyStopIterationObject *self)

{

PyObject_GC_UnTrack(self);

StopIteration_clear(self);

Py_TYPE(self)->tp_free((PyObject *)self);

}

static int

StopIteration_traverse(PyStopIterationObject *self, visitproc visit, void *arg)

{

Py_VISIT(self->value);

return BaseException_traverse((PyBaseExceptionObject *)self, visit, arg);

}

ComplexExtendsException(

PyExc_Exception, /* base */

StopIteration, /* name */

StopIteration, /* prefix for *_init, etc */

0, /* new */

0, /* methods */

StopIteration_members, /* members */

0, /* getset */

0, /* str */

"Signal the end from iterator.__next__()."

);

/*

* GeneratorExit extends BaseException

*/

SimpleExtendsException(PyExc_BaseException, GeneratorExit,

"Request that a generator exit.");

/*

* SystemExit extends BaseException

*/

static int

SystemExit_init(PySystemExitObject *self, PyObject *args, PyObject *kwds)

{

Py_ssize_t size = PyTuple_GET_SIZE(args);

if (BaseException_init((PyBaseExceptionObject *)self, args, kwds) == -1)

return -1;

if (size == 0)

return 0;

if (size == 1) {

Py_INCREF(PyTuple_GET_ITEM(args, 0));

Py_XSETREF(self->code, PyTuple_GET_ITEM(args, 0));

}

else { /* size > 1 */

Py_INCREF(args);

Py_XSETREF(self->code, args);

}

return 0;

}

static int

SystemExit_clear(PySystemExitObject *self)

{

Py_CLEAR(self->code);

return BaseException_clear((PyBaseExceptionObject *)self);

}

static void

SystemExit_dealloc(PySystemExitObject *self)

{

_PyObject_GC_UNTRACK(self);

SystemExit_clear(self);

Py_TYPE(self)->tp_free((PyObject *)self);

}

static int

SystemExit_traverse(PySystemExitObject *self, visitproc visit, void *arg)

{

Py_VISIT(self->code);

return BaseException_traverse((PyBaseExceptionObject *)self, visit, arg);

}

static PyMemberDef SystemExit_members[] = {

{"code", T_OBJECT, offsetof(PySystemExitObject, code), 0,

PyDoc_STR("exception code")},

{NULL} /* Sentinel */

};

ComplexExtendsException(PyExc_BaseException, SystemExit, SystemExit,

0, 0, SystemExit_members, 0, 0,

"Request to exit from the interpreter.");

/*

* BaseExceptionGroup extends BaseException

* ExceptionGroup extends BaseExceptionGroup and Exception

*/

static inline PyBaseExceptionGroupObject*

_PyBaseExceptionGroupObject_cast(PyObject *exc)

{

assert(_PyBaseExceptionGroup_Check(exc));

return (PyBaseExceptionGroupObject *)exc;

}

static PyObject *

BaseExceptionGroup_new(PyTypeObject *type, PyObject *args, PyObject *kwds)

{

struct _Py_exc_state *state = get_exc_state();

PyTypeObject *PyExc_ExceptionGroup =

(PyTypeObject*)state->PyExc_ExceptionGroup;

PyObject *message = NULL;

PyObject *exceptions = NULL;

if (!PyArg_ParseTuple(args, "UO", &message, &exceptions)) {

return NULL;

}

if (!PySequence_Check(exceptions)) {

PyErr_SetString(

PyExc_TypeError,

"second argument (exceptions) must be a sequence");

return NULL;

}

exceptions = PySequence_Tuple(exceptions);

if (!exceptions) {

return NULL;

}

/* We are now holding a ref to the exceptions tuple */

Py_ssize_t numexcs = PyTuple_GET_SIZE(exceptions);

if (numexcs == 0) {

PyErr_SetString(

PyExc_ValueError,

"second argument (exceptions) must be a non-empty sequence");

goto error;

}

bool nested_base_exceptions = false;

for (Py_ssize_t i = 0; i < numexcs; i++) {

PyObject *exc = PyTuple_GET_ITEM(exceptions, i);

if (!exc) {

goto error;

}

if (!PyExceptionInstance_Check(exc)) {

PyErr_Format(

PyExc_ValueError,

"Item %d of second argument (exceptions) is not an exception",

i);

goto error;

}

int is_nonbase_exception = PyObject_IsInstance(exc, PyExc_Exception);

if (is_nonbase_exception < 0) {

goto error;

}

else if (is_nonbase_exception == 0) {

nested_base_exceptions = true;

}

}

PyTypeObject *cls = type;

if (cls == PyExc_ExceptionGroup) {

if (nested_base_exceptions) {

PyErr_SetString(PyExc_TypeError,

"Cannot nest BaseExceptions in an ExceptionGroup");

goto error;

}

}

else if (cls == (PyTypeObject*)PyExc_BaseExceptionGroup) {

if (!nested_base_exceptions) {

/* All nested exceptions are Exception subclasses,

* wrap them in an ExceptionGroup

*/

cls = PyExc_ExceptionGroup;

}

}

else {

/* Do nothing - we don't interfere with subclasses */

}

if (!cls) {

/* Don't crash during interpreter shutdown

* (PyExc_ExceptionGroup may have been cleared)

*/

cls = (PyTypeObject*)PyExc_BaseExceptionGroup;

}

PyBaseExceptionGroupObject *self =

_PyBaseExceptionGroupObject_cast(BaseException_new(cls, args, kwds));

if (!self) {

goto error;

}

self->msg = Py_NewRef(message);

self->excs = exceptions;

return (PyObject*)self;

error:

Py_DECREF(exceptions);

return NULL;

}

PyObject *

_PyExc_CreateExceptionGroup(const char *msg_str, PyObject *excs)

{

PyObject *msg = PyUnicode_FromString(msg_str);

if (!msg) {

return NULL;

}

PyObject *args = PyTuple_Pack(2, msg, excs);

Py_DECREF(msg);

if (!args) {

return NULL;

}

PyObject *result = PyObject_CallObject(PyExc_BaseExceptionGroup, args);

Py_DECREF(args);

return result;

}

static int

BaseExceptionGroup_init(PyBaseExceptionGroupObject *self,

PyObject *args, PyObject *kwds)

{

if (!_PyArg_NoKeywords(Py_TYPE(self)->tp_name, kwds)) {

return -1;

}

if (BaseException_init((PyBaseExceptionObject *)self, args, kwds) == -1) {

return -1;

}

return 0;

}

static int

BaseExceptionGroup_clear(PyBaseExceptionGroupObject *self)

{

Py_CLEAR(self->msg);

Py_CLEAR(self->excs);

return BaseException_clear((PyBaseExceptionObject *)self);

}

static void

BaseExceptionGroup_dealloc(PyBaseExceptionGroupObject *self)

{

_PyObject_GC_UNTRACK(self);

BaseExceptionGroup_clear(self);

Py_TYPE(self)->tp_free((PyObject *)self);

}

static int

BaseExceptionGroup_traverse(PyBaseExceptionGroupObject *self,

visitproc visit, void *arg)

{

Py_VISIT(self->msg);

Py_VISIT(self->excs);

return BaseException_traverse((PyBaseExceptionObject *)self, visit, arg);

}

static PyObject *

BaseExceptionGroup_str(PyBaseExceptionGroupObject *self)

{

assert(self->msg);

assert(PyUnicode_Check(self->msg));

return Py_NewRef(self->msg);

}

static PyObject *

BaseExceptionGroup_derive(PyObject *self_, PyObject *args)

{

PyBaseExceptionGroupObject *self = _PyBaseExceptionGroupObject_cast(self_);

PyObject *excs = NULL;

if (!PyArg_ParseTuple(args, "O", &excs)) {

return NULL;

}

PyObject *init_args = PyTuple_Pack(2, self->msg, excs);

if (!init_args) {

return NULL;

}

PyObject *eg = PyObject_CallObject(

PyExc_BaseExceptionGroup, init_args);

Py_DECREF(init_args);

return eg;

}

static int

exceptiongroup_subset(

PyBaseExceptionGroupObject *_orig, PyObject *excs, PyObject **result)

{

/* Sets *result to an ExceptionGroup wrapping excs with metadata from

* _orig. If excs is empty, sets *result to NULL.

* Returns 0 on success and -1 on error.

* This function is used by split() to construct the match/rest parts,

* so excs is the matching or non-matching sub-sequence of orig->excs

* (this function does not verify that it is a subsequence).

*/

PyObject *orig = (PyObject *)_orig;

*result = NULL;

Py_ssize_t num_excs = PySequence_Size(excs);

if (num_excs < 0) {

return -1;

}

else if (num_excs == 0) {

return 0;

}

PyObject *eg = PyObject_CallMethod(

orig, "derive", "(O)", excs);

if (!eg) {

return -1;

}

if (!_PyBaseExceptionGroup_Check(eg)) {

PyErr_SetString(PyExc_TypeError,

"derive must return an instance of BaseExceptionGroup");

goto error;

}

/* Now we hold a reference to the new eg */

PyObject *tb = PyException_GetTraceback(orig);

if (tb) {

int res = PyException_SetTraceback(eg, tb);

Py_DECREF(tb);

if (res < 0) {

goto error;

}

}

PyException_SetContext(eg, PyException_GetContext(orig));

PyException_SetCause(eg, PyException_GetCause(orig));

*result = eg;

return 0;

error:

Py_DECREF(eg);

return -1;

}

typedef enum {

/* Exception type or tuple of thereof */

EXCEPTION_GROUP_MATCH_BY_TYPE = 0,

/* A PyFunction returning True for matching exceptions */

EXCEPTION_GROUP_MATCH_BY_PREDICATE = 1,

/* A set of leaf exceptions to include in the result.

* This matcher type is used internally by the interpreter

* to construct reraised exceptions.

*/

EXCEPTION_GROUP_MATCH_INSTANCES = 2

} _exceptiongroup_split_matcher_type;

static int

get_matcher_type(PyObject *value,

_exceptiongroup_split_matcher_type *type)

{

assert(value);

if (PyFunction_Check(value)) {

*type = EXCEPTION_GROUP_MATCH_BY_PREDICATE;

return 0;

}

if (PyExceptionClass_Check(value)) {

*type = EXCEPTION_GROUP_MATCH_BY_TYPE;

return 0;

}

if (PyTuple_CheckExact(value)) {

Py_ssize_t n = PyTuple_GET_SIZE(value);

for (Py_ssize_t i=0; i<n; i++) {

if (!PyExceptionClass_Check(PyTuple_GET_ITEM(value, i))) {

goto error;

}

}

*type = EXCEPTION_GROUP_MATCH_BY_TYPE;

return 0;

}

error:

PyErr_SetString(

PyExc_TypeError,

"expected a function, exception type or tuple of exception types");

return -1;

}

static int

exceptiongroup_split_check_match(PyObject *exc,

_exceptiongroup_split_matcher_type matcher_type,

PyObject *matcher_value)

{

switch (matcher_type) {

case EXCEPTION_GROUP_MATCH_BY_TYPE: {

assert(PyExceptionClass_Check(matcher_value) ||

PyTuple_CheckExact(matcher_value));

return PyErr_GivenExceptionMatches(exc, matcher_value);

}

case EXCEPTION_GROUP_MATCH_BY_PREDICATE: {

assert(PyFunction_Check(matcher_value));

PyObject *exc_matches = PyObject_CallOneArg(matcher_value, exc);

if (exc_matches == NULL) {

return -1;

}

int is_true = PyObject_IsTrue(exc_matches);

Py_DECREF(exc_matches);

return is_true;

}

case EXCEPTION_GROUP_MATCH_INSTANCES: {

assert(PySet_Check(matcher_value));

if (!_PyBaseExceptionGroup_Check(exc)) {

return PySet_Contains(matcher_value, exc);

}

return 0;

}

}

return 0;

}

typedef struct {

PyObject *match;

PyObject *rest;

} _exceptiongroup_split_result;

static int

exceptiongroup_split_recursive(PyObject *exc,

_exceptiongroup_split_matcher_type matcher_type,

PyObject *matcher_value,

bool construct_rest,

_exceptiongroup_split_result *result)

{