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pythongh-76785: Move _Py_excinfo Functions Out of the Internal C-API (p…
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…ythongh-111715)

I added _Py_excinfo to the internal API (and added its functions in Python/errors.c) in pythongh-111530 (9322ce9).  Since then I've had a nagging sense that I should have added the type and functions in its own PR.  While I do plan on using _Py_excinfo outside crossinterp.c very soon (see pythongh-111572/pythongh-111573), I'd still feel more comfortable if the _Py_excinfo stuff went in as its own PR.  Hence, here we are.

(FWIW, I may combine that with pythongh-111572, which I may, in turn, combine with pythongh-111573.  We'll see.)
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@ericsnowcurrently @hugovk
ericsnowcurrently authored and hugovk committed Nov 8, 2023
1 parent 7af88ed commit 8ac1b5b
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Showing 4 changed files with 134 additions and 199 deletions.
11 changes: 11 additions & 0 deletions Include/internal/pycore_crossinterp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -164,6 +164,17 @@ extern void _PyXI_Fini(PyInterpreterState *interp);
/* short-term data sharing */
/***************************/

// Ultimately we'd like to preserve enough information about the
// exception and traceback that we could re-constitute (or at least
// simulate, a la traceback.TracebackException), and even chain, a copy
// of the exception in the calling interpreter.

typedef struct _excinfo {
const char *type;
const char *msg;
} _Py_excinfo;


typedef enum error_code {
_PyXI_ERR_NO_ERROR = 0,
_PyXI_ERR_UNCAUGHT_EXCEPTION = -1,
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24 changes: 0 additions & 24 deletions Include/internal/pycore_pyerrors.h
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Original file line number Diff line number Diff line change
Expand Up @@ -68,30 +68,6 @@ extern PyStatus _PyErr_InitTypes(PyInterpreterState *);
extern void _PyErr_FiniTypes(PyInterpreterState *);


/* exception snapshots */

// Ultimately we'd like to preserve enough information about the
// exception and traceback that we could re-constitute (or at least
// simulate, a la traceback.TracebackException), and even chain, a copy
// of the exception in the calling interpreter.

typedef struct _excinfo {
const char *type;
const char *msg;
} _Py_excinfo;

extern void _Py_excinfo_Clear(_Py_excinfo *info);
extern int _Py_excinfo_Copy(_Py_excinfo *dest, _Py_excinfo *src);
extern const char * _Py_excinfo_InitFromException(
_Py_excinfo *info,
PyObject *exc);
extern void _Py_excinfo_Apply(_Py_excinfo *info, PyObject *exctype);
extern const char * _Py_excinfo_AsUTF8(
_Py_excinfo *info,
char *buf,
size_t bufsize);


/* other API */

static inline PyObject* _PyErr_Occurred(PyThreadState *tstate)
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123 changes: 123 additions & 0 deletions Python/crossinterp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -800,6 +800,17 @@ _xidregistry_fini(struct _xidregistry *registry)
/* convenience utilities */
/*************************/

static const char *
_copy_raw_string(const char *str)
{
char *copied = PyMem_RawMalloc(strlen(str)+1);
if (copied == NULL) {
return NULL;
}
strcpy(copied, str);
return copied;
}

static const char *
_copy_string_obj_raw(PyObject *strobj)
{
Expand Down Expand Up @@ -835,6 +846,118 @@ _release_xid_data(_PyCrossInterpreterData *data, int rawfree)
}


/* exception snapshots */

static int
_exc_type_name_as_utf8(PyObject *exc, const char **p_typename)
{
// XXX Use PyObject_GetAttrString(Py_TYPE(exc), '__name__')?
PyObject *nameobj = PyUnicode_FromString(Py_TYPE(exc)->tp_name);
if (nameobj == NULL) {
assert(PyErr_Occurred());
*p_typename = "unable to format exception type name";
return -1;
}
const char *name = PyUnicode_AsUTF8(nameobj);
if (name == NULL) {
assert(PyErr_Occurred());
Py_DECREF(nameobj);
*p_typename = "unable to encode exception type name";
return -1;
}
name = _copy_raw_string(name);
Py_DECREF(nameobj);
if (name == NULL) {
*p_typename = "out of memory copying exception type name";
return -1;
}
*p_typename = name;
return 0;
}

static int
_exc_msg_as_utf8(PyObject *exc, const char **p_msg)
{
PyObject *msgobj = PyObject_Str(exc);
if (msgobj == NULL) {
assert(PyErr_Occurred());
*p_msg = "unable to format exception message";
return -1;
}
const char *msg = PyUnicode_AsUTF8(msgobj);
if (msg == NULL) {
assert(PyErr_Occurred());
Py_DECREF(msgobj);
*p_msg = "unable to encode exception message";
return -1;
}
msg = _copy_raw_string(msg);
Py_DECREF(msgobj);
if (msg == NULL) {
assert(PyErr_ExceptionMatches(PyExc_MemoryError));
*p_msg = "out of memory copying exception message";
return -1;
}
*p_msg = msg;
return 0;
}

static void
_Py_excinfo_Clear(_Py_excinfo *info)
{
if (info->type != NULL) {
PyMem_RawFree((void *)info->type);
}
if (info->msg != NULL) {
PyMem_RawFree((void *)info->msg);
}
*info = (_Py_excinfo){ NULL };
}

static const char *
_Py_excinfo_InitFromException(_Py_excinfo *info, PyObject *exc)
{
assert(exc != NULL);

// Extract the exception type name.
const char *typename = NULL;
if (_exc_type_name_as_utf8(exc, &typename) < 0) {
assert(typename != NULL);
return typename;
}

// Extract the exception message.
const char *msg = NULL;
if (_exc_msg_as_utf8(exc, &msg) < 0) {
assert(msg != NULL);
return msg;
}

info->type = typename;
info->msg = msg;
return NULL;
}

static void
_Py_excinfo_Apply(_Py_excinfo *info, PyObject *exctype)
{
if (info->type != NULL) {
if (info->msg != NULL) {
PyErr_Format(exctype, "%s: %s", info->type, info->msg);
}
else {
PyErr_SetString(exctype, info->type);
}
}
else if (info->msg != NULL) {
PyErr_SetString(exctype, info->msg);
}
else {
PyErr_SetNone(exctype);
}
}


/***************************/
/* short-term data sharing */
/***************************/
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175 changes: 0 additions & 175 deletions Python/errors.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1934,178 +1934,3 @@ PyErr_ProgramTextObject(PyObject *filename, int lineno)
{
return _PyErr_ProgramDecodedTextObject(filename, lineno, NULL);
}


/***********************/
/* exception snapshots */
/***********************/

static const char *
_copy_raw_string(const char *str)
{
char *copied = PyMem_RawMalloc(strlen(str)+1);
if (copied == NULL) {
return NULL;
}
strcpy(copied, str);
return copied;
}

static int
_exc_type_name_as_utf8(PyObject *exc, const char **p_typename)
{
// XXX Use PyObject_GetAttrString(Py_TYPE(exc), '__name__')?
PyObject *nameobj = PyUnicode_FromString(Py_TYPE(exc)->tp_name);
if (nameobj == NULL) {
assert(PyErr_Occurred());
*p_typename = "unable to format exception type name";
return -1;
}
const char *name = PyUnicode_AsUTF8(nameobj);
if (name == NULL) {
assert(PyErr_Occurred());
Py_DECREF(nameobj);
*p_typename = "unable to encode exception type name";
return -1;
}
name = _copy_raw_string(name);
Py_DECREF(nameobj);
if (name == NULL) {
*p_typename = "out of memory copying exception type name";
return -1;
}
*p_typename = name;
return 0;
}

static int
_exc_msg_as_utf8(PyObject *exc, const char **p_msg)
{
PyObject *msgobj = PyObject_Str(exc);
if (msgobj == NULL) {
assert(PyErr_Occurred());
*p_msg = "unable to format exception message";
return -1;
}
const char *msg = PyUnicode_AsUTF8(msgobj);
if (msg == NULL) {
assert(PyErr_Occurred());
Py_DECREF(msgobj);
*p_msg = "unable to encode exception message";
return -1;
}
msg = _copy_raw_string(msg);
Py_DECREF(msgobj);
if (msg == NULL) {
assert(PyErr_ExceptionMatches(PyExc_MemoryError));
*p_msg = "out of memory copying exception message";
return -1;
}
*p_msg = msg;
return 0;
}

void
_Py_excinfo_Clear(_Py_excinfo *info)
{
if (info->type != NULL) {
PyMem_RawFree((void *)info->type);
}
if (info->msg != NULL) {
PyMem_RawFree((void *)info->msg);
}
*info = (_Py_excinfo){ NULL };
}

int
_Py_excinfo_Copy(_Py_excinfo *dest, _Py_excinfo *src)
{
// XXX Clear dest first?

if (src->type == NULL) {
dest->type = NULL;
}
else {
dest->type = _copy_raw_string(src->type);
if (dest->type == NULL) {
return -1;
}
}

if (src->msg == NULL) {
dest->msg = NULL;
}
else {
dest->msg = _copy_raw_string(src->msg);
if (dest->msg == NULL) {
return -1;
}
}

return 0;
}

const char *
_Py_excinfo_InitFromException(_Py_excinfo *info, PyObject *exc)
{
assert(exc != NULL);

// Extract the exception type name.
const char *typename = NULL;
if (_exc_type_name_as_utf8(exc, &typename) < 0) {
assert(typename != NULL);
return typename;
}

// Extract the exception message.
const char *msg = NULL;
if (_exc_msg_as_utf8(exc, &msg) < 0) {
assert(msg != NULL);
return msg;
}

info->type = typename;
info->msg = msg;
return NULL;
}

void
_Py_excinfo_Apply(_Py_excinfo *info, PyObject *exctype)
{
if (info->type != NULL) {
if (info->msg != NULL) {
PyErr_Format(exctype, "%s: %s", info->type, info->msg);
}
else {
PyErr_SetString(exctype, info->type);
}
}
else if (info->msg != NULL) {
PyErr_SetString(exctype, info->msg);
}
else {
PyErr_SetNone(exctype);
}
}

const char *
_Py_excinfo_AsUTF8(_Py_excinfo *info, char *buf, size_t bufsize)
{
// XXX Dynamically allocate if no buf provided?
assert(buf != NULL);
if (info->type != NULL) {
if (info->msg != NULL) {
snprintf(buf, bufsize, "%s: %s", info->type, info->msg);
return buf;
}
else {
return info->type;
}
}
else if (info->msg != NULL) {
return info->msg;
}
else {
return NULL;
}
}

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