#include "Python.h"

#include "pycore_initconfig.h"

#include "pycore_interp.h" // PyInterpreterState.warnings

#include "pycore_long.h" // _PyLong_GetZero()

#include "pycore_pyerrors.h"

#include "pycore_pystate.h" // _PyThreadState_GET()

#include "pycore_frame.h"

#include "pycore_sysmodule.h" // _PySys_GetOptionalAttr()

#include "clinic/_warnings.c.h"

#define MODULE_NAME "_warnings"

PyDoc_STRVAR(warnings__doc__,

MODULE_NAME " provides basic warning filtering support.\n"

"It is a helper module to speed up interpreter start-up.");

typedef struct _warnings_runtime_state WarningsState;

static inline int

check_interp(PyInterpreterState *interp)

{

if (interp == NULL) {

PyErr_SetString(PyExc_RuntimeError,

"warnings_get_state: could not identify "

"current interpreter");

return 0;

}

return 1;

}

static inline PyInterpreterState *

get_current_interp(void)

{

PyInterpreterState *interp = _PyInterpreterState_GET();

return check_interp(interp) ? interp : NULL;

}

static inline PyThreadState *

get_current_tstate(void)

{

PyThreadState *tstate = _PyThreadState_GET();

if (tstate == NULL) {

(void)check_interp(NULL);

return NULL;

}

return check_interp(tstate->interp) ? tstate : NULL;

}

static WarningsState *

warnings_get_state(PyInterpreterState *interp)

{

return &interp->warnings;

}

static void

warnings_clear_state(WarningsState *st)

{

Py_CLEAR(st->filters);

Py_CLEAR(st->once_registry);

Py_CLEAR(st->default_action);

}

#ifndef Py_DEBUG

static PyObject *

create_filter(PyObject *category, PyObject *action_str, const char *modname)

{

PyObject *modname_obj = NULL;

/* Default to "no module name" for initial filter set */

if (modname != NULL) {

modname_obj = PyUnicode_InternFromString(modname);

if (modname_obj == NULL) {

return NULL;

}

} else {

modname_obj = Py_NewRef(Py_None);

}

/* This assumes the line number is zero for now. */

PyObject *filter = PyTuple_Pack(5, action_str, Py_None,

category, modname_obj, _PyLong_GetZero());

Py_DECREF(modname_obj);

return filter;

}

static PyObject *

init_filters(PyInterpreterState *interp)

{

#ifdef Py_DEBUG

/* Py_DEBUG builds show all warnings by default */

return PyList_New(0);

/* Other builds ignore a number of warning categories by default */

PyObject *filters = PyList_New(5);

if (filters == NULL) {

return NULL;

}

size_t pos = 0; /* Post-incremented in each use. */

#define ADD(TYPE, ACTION, MODNAME) \

PyList_SET_ITEM(filters, pos++, \

create_filter(TYPE, &_Py_ID(ACTION), MODNAME));

ADD(PyExc_DeprecationWarning, default, "__main__");

ADD(PyExc_DeprecationWarning, ignore, NULL);

ADD(PyExc_PendingDeprecationWarning, ignore, NULL);

ADD(PyExc_ImportWarning, ignore, NULL);

ADD(PyExc_ResourceWarning, ignore, NULL);

#undef ADD

for (size_t x = 0; x < pos; x++) {

if (PyList_GET_ITEM(filters, x) == NULL) {

Py_DECREF(filters);

return NULL;

}

}

return filters;

}

_PyWarnings_InitState(PyInterpreterState *interp)

{

WarningsState *st = &interp->warnings;

if (st->filters == NULL) {

st->filters = init_filters(interp);

if (st->filters == NULL) {

return -1;

}

}

if (st->once_registry == NULL) {

st->once_registry = PyDict_New();

if (st->once_registry == NULL) {

return -1;

}

}

if (st->default_action == NULL) {

st->default_action = PyUnicode_FromString("default");

if (st->default_action == NULL) {

return -1;

}

}

st->filters_version = 0;

return 0;

}

static int

check_matched(PyInterpreterState *interp, PyObject *obj, PyObject *arg)

{

PyObject *result;

int rc;

/* A 'None' filter always matches */

if (obj == Py_None)

return 1;

/* An internal plain text default filter must match exactly */

if (PyUnicode_CheckExact(obj)) {

int cmp_result = PyUnicode_Compare(obj, arg);

if (cmp_result == -1 && PyErr_Occurred()) {

return -1;

}

return !cmp_result;

}

/* Otherwise assume a regex filter and call its match() method */

result = PyObject_CallMethodOneArg(obj, &_Py_ID(match), arg);

if (result == NULL)

return -1;

rc = PyObject_IsTrue(result);

Py_DECREF(result);

return rc;

}

#define GET_WARNINGS_ATTR(interp, ATTR, try_import) \

get_warnings_attr(interp, &_Py_ID(ATTR), try_import)

static PyObject *

get_warnings_attr(PyInterpreterState *interp, PyObject *attr, int try_import)

{

PyObject *warnings_module, *obj;

/* don't try to import after the start of the Python finallization */

if (try_import && !_Py_IsInterpreterFinalizing(interp)) {

warnings_module = PyImport_Import(&_Py_ID(warnings));

if (warnings_module == NULL) {

/* Fallback to the C implementation if we cannot get

if (PyErr_ExceptionMatches(PyExc_ImportError)) {

PyErr_Clear();

}

return NULL;

}

}

else {

/* if we're so late into Python finalization that the module dict is

if (!_PyImport_GetModules(interp)) {

return NULL;

}

warnings_module = PyImport_GetModule(&_Py_ID(warnings));

if (warnings_module == NULL)

return NULL;

}

(void)_PyObject_LookupAttr(warnings_module, attr, &obj);

Py_DECREF(warnings_module);

return obj;

}

static PyObject *

get_once_registry(PyInterpreterState *interp)

{

PyObject *registry;

WarningsState *st = warnings_get_state(interp);

if (st == NULL) {

return NULL;

}

registry = GET_WARNINGS_ATTR(interp, onceregistry, 0);

if (registry == NULL) {

if (PyErr_Occurred())

return NULL;

assert(st->once_registry);

return st->once_registry;

}

if (!PyDict_Check(registry)) {

PyErr_Format(PyExc_TypeError,

MODULE_NAME ".onceregistry must be a dict, "

"not '%.200s'",

Py_TYPE(registry)->tp_name);

Py_DECREF(registry);

return NULL;

}

Py_SETREF(st->once_registry, registry);

return registry;

}

static PyObject *

get_default_action(PyInterpreterState *interp)

{

PyObject *default_action;

WarningsState *st = warnings_get_state(interp);

if (st == NULL) {

return NULL;

}

default_action = GET_WARNINGS_ATTR(interp, defaultaction, 0);

if (default_action == NULL) {

if (PyErr_Occurred()) {

return NULL;

}

assert(st->default_action);

return st->default_action;

}

if (!PyUnicode_Check(default_action)) {

PyErr_Format(PyExc_TypeError,

MODULE_NAME ".defaultaction must be a string, "

"not '%.200s'",

Py_TYPE(default_action)->tp_name);

Py_DECREF(default_action);

return NULL;

}

Py_SETREF(st->default_action, default_action);

return default_action;

}

static PyObject*

get_filter(PyInterpreterState *interp, PyObject *category,

PyObject *text, Py_ssize_t lineno,

PyObject *module, PyObject **item)

{

PyObject *action;

Py_ssize_t i;

PyObject *warnings_filters;

WarningsState *st = warnings_get_state(interp);

if (st == NULL) {

return NULL;

}

warnings_filters = GET_WARNINGS_ATTR(interp, filters, 0);

if (warnings_filters == NULL) {

if (PyErr_Occurred())

return NULL;

}

else {

Py_SETREF(st->filters, warnings_filters);

}

PyObject *filters = st->filters;

if (filters == NULL || !PyList_Check(filters)) {

PyErr_SetString(PyExc_ValueError,

MODULE_NAME ".filters must be a list");

return NULL;

}

/* WarningsState.filters could change while we are iterating over it. */

for (i = 0; i < PyList_GET_SIZE(filters); i++) {

PyObject *tmp_item, *action, *msg, *cat, *mod, *ln_obj;

Py_ssize_t ln;

int is_subclass, good_msg, good_mod;

tmp_item = PyList_GET_ITEM(filters, i);

if (!PyTuple_Check(tmp_item) || PyTuple_GET_SIZE(tmp_item) != 5) {

PyErr_Format(PyExc_ValueError,

MODULE_NAME ".filters item %zd isn't a 5-tuple", i);

return NULL;

}

/* Python code: action, msg, cat, mod, ln = item */

Py_INCREF(tmp_item);

action = PyTuple_GET_ITEM(tmp_item, 0);

msg = PyTuple_GET_ITEM(tmp_item, 1);

cat = PyTuple_GET_ITEM(tmp_item, 2);

mod = PyTuple_GET_ITEM(tmp_item, 3);

ln_obj = PyTuple_GET_ITEM(tmp_item, 4);

if (!PyUnicode_Check(action)) {

PyErr_Format(PyExc_TypeError,

"action must be a string, not '%.200s'",

Py_TYPE(action)->tp_name);

Py_DECREF(tmp_item);

return NULL;

}

good_msg = check_matched(interp, msg, text);

if (good_msg == -1) {

Py_DECREF(tmp_item);

return NULL;

}

good_mod = check_matched(interp, mod, module);

if (good_mod == -1) {

Py_DECREF(tmp_item);

return NULL;

}

is_subclass = PyObject_IsSubclass(category, cat);

if (is_subclass == -1) {

Py_DECREF(tmp_item);

return NULL;

}

ln = PyLong_AsSsize_t(ln_obj);

if (ln == -1 && PyErr_Occurred()) {

Py_DECREF(tmp_item);

return NULL;

}

if (good_msg && is_subclass && good_mod && (ln == 0 || lineno == ln)) {

*item = tmp_item;

return action;

}

Py_DECREF(tmp_item);

}

action = get_default_action(interp);

if (action != NULL) {

*item = Py_NewRef(Py_None);

return action;

}

return NULL;

}

static int

already_warned(PyInterpreterState *interp, PyObject *registry, PyObject *key,

int should_set)

{

PyObject *version_obj, *already_warned;

if (key == NULL)

return -1;

WarningsState *st = warnings_get_state(interp);

if (st == NULL) {

return -1;

}

version_obj = _PyDict_GetItemWithError(registry, &_Py_ID(version));

if (version_obj == NULL

|| !PyLong_CheckExact(version_obj)

|| PyLong_AsLong(version_obj) != st->filters_version)

{

if (PyErr_Occurred()) {

return -1;

}

PyDict_Clear(registry);

version_obj = PyLong_FromLong(st->filters_version);

if (version_obj == NULL)

return -1;

if (PyDict_SetItem(registry, &_Py_ID(version), version_obj) < 0) {

Py_DECREF(version_obj);

return -1;

}

Py_DECREF(version_obj);

}

else {

already_warned = PyDict_GetItemWithError(registry, key);

if (already_warned != NULL) {

int rc = PyObject_IsTrue(already_warned);

if (rc != 0)

return rc;

}

else if (PyErr_Occurred()) {

return -1;

}

}

/* This warning wasn't found in the registry, set it. */

if (should_set)

return PyDict_SetItem(registry, key, Py_True);

return 0;

}

static PyObject *

normalize_module(PyObject *filename)

{

PyObject *module;

int kind;

const void *data;

Py_ssize_t len;

len = PyUnicode_GetLength(filename);

if (len < 0)

return NULL;

if (len == 0)

return PyUnicode_FromString("<unknown>");

kind = PyUnicode_KIND(filename);

data = PyUnicode_DATA(filename);

/* if filename.endswith(".py"): */

if (len >= 3 &&

PyUnicode_READ(kind, data, len-3) == '.' &&

PyUnicode_READ(kind, data, len-2) == 'p' &&

PyUnicode_READ(kind, data, len-1) == 'y')

{

module = PyUnicode_Substring(filename, 0, len-3);

}

else {

module = Py_NewRef(filename);

}

return module;

}

static int

update_registry(PyInterpreterState *interp, PyObject *registry, PyObject *text,

PyObject *category, int add_zero)

{

PyObject *altkey;

int rc;

if (add_zero)

altkey = PyTuple_Pack(3, text, category, _PyLong_GetZero());

else

altkey = PyTuple_Pack(2, text, category);

rc = already_warned(interp, registry, altkey, 1);

Py_XDECREF(altkey);

return rc;

}

static void

show_warning(PyThreadState *tstate, PyObject *filename, int lineno,

PyObject *text, PyObject *category, PyObject *sourceline)

{

PyObject *f_stderr = NULL;

PyObject *name;

char lineno_str[128];

PyOS_snprintf(lineno_str, sizeof(lineno_str), ":%d: ", lineno);

name = PyObject_GetAttr(category, &_Py_ID(__name__));

if (name == NULL) {

goto error;

}

if (_PySys_GetOptionalAttr(&_Py_ID(stderr), &f_stderr) <= 0) {

fprintf(stderr, "lost sys.stderr\n");

goto error;

}

/* Print "filename:lineno: category: text\n" */

if (PyFile_WriteObject(filename, f_stderr, Py_PRINT_RAW) < 0)

goto error;

if (PyFile_WriteString(lineno_str, f_stderr) < 0)

goto error;

if (PyFile_WriteObject(name, f_stderr, Py_PRINT_RAW) < 0)

goto error;

if (PyFile_WriteString(": ", f_stderr) < 0)

goto error;

if (PyFile_WriteObject(text, f_stderr, Py_PRINT_RAW) < 0)

goto error;

if (PyFile_WriteString("\n", f_stderr) < 0)

goto error;

Py_CLEAR(name);

/* Print " source_line\n" */

if (sourceline) {

int kind;

const void *data;

Py_ssize_t i, len;

Py_UCS4 ch;

PyObject *truncated;

if (PyUnicode_READY(sourceline) < 1)

goto error;

kind = PyUnicode_KIND(sourceline);

data = PyUnicode_DATA(sourceline);

len = PyUnicode_GET_LENGTH(sourceline);

for (i=0; i<len; i++) {

ch = PyUnicode_READ(kind, data, i);

if (ch != ' ' && ch != '\t' && ch != '\014')

break;

}

truncated = PyUnicode_Substring(sourceline, i, len);

if (truncated == NULL)

goto error;

PyFile_WriteObject(sourceline, f_stderr, Py_PRINT_RAW);

Py_DECREF(truncated);

PyFile_WriteString("\n", f_stderr);

}

else {

_Py_DisplaySourceLine(f_stderr, filename, lineno, 2, NULL, NULL);

}

error:

Py_XDECREF(f_stderr);

Py_XDECREF(name);

PyErr_Clear();

}

static int

call_show_warning(PyThreadState *tstate, PyObject *category,

PyObject *text, PyObject *message,

PyObject *filename, int lineno, PyObject *lineno_obj,

PyObject *sourceline, PyObject *source)

{

PyObject *show_fn, *msg, *res, *warnmsg_cls = NULL;

PyInterpreterState *interp = tstate->interp;

/* If the source parameter is set, try to get the Python implementation.

show_fn = GET_WARNINGS_ATTR(interp, _showwarnmsg, source != NULL);

if (show_fn == NULL) {

if (PyErr_Occurred())

return -1;

show_warning(tstate, filename, lineno, text, category, sourceline);

return 0;

}

if (!PyCallable_Check(show_fn)) {

PyErr_SetString(PyExc_TypeError,

"warnings._showwarnmsg() must be set to a callable");

goto error;

}

warnmsg_cls = GET_WARNINGS_ATTR(interp, WarningMessage, 0);

if (warnmsg_cls == NULL) {

if (!PyErr_Occurred()) {

PyErr_SetString(PyExc_RuntimeError,

"unable to get warnings.WarningMessage");

}

goto error;

}

msg = PyObject_CallFunctionObjArgs(warnmsg_cls, message, category,

filename, lineno_obj, Py_None, Py_None, source,

NULL);

Py_DECREF(warnmsg_cls);

if (msg == NULL)

goto error;

res = PyObject_CallOneArg(show_fn, msg);

Py_DECREF(show_fn);

Py_DECREF(msg);

if (res == NULL)

return -1;

Py_DECREF(res);

return 0;

error:

Py_XDECREF(show_fn);

return -1;

}

static PyObject *

warn_explicit(PyThreadState *tstate, PyObject *category, PyObject *message,

PyObject *filename, int lineno,

PyObject *module, PyObject *registry, PyObject *sourceline,

PyObject *source)

{

PyObject *key = NULL, *text = NULL, *result = NULL, *lineno_obj = NULL;

PyObject *item = NULL;

PyObject *action;

int rc;

PyInterpreterState *interp = tstate->interp;

/* module can be None if a warning is emitted late during Python shutdown.

if (module == Py_None)

Py_RETURN_NONE;

if (registry && !PyDict_Check(registry) && (registry != Py_None)) {

PyErr_SetString(PyExc_TypeError, "'registry' must be a dict or None");

return NULL;

}

/* Normalize module. */

if (module == NULL) {

module = normalize_module(filename);

if (module == NULL)

return NULL;

}

else

Py_INCREF(module);

/* Normalize message. */

Py_INCREF(message); /* DECREF'ed in cleanup. */

rc = PyObject_IsInstance(message, PyExc_Warning);

if (rc == -1) {

goto cleanup;

}

if (rc == 1) {

text = PyObject_Str(message);

if (text == NULL)

goto cleanup;

category = (PyObject*)Py_TYPE(message);

}

else {

text = message;

message = PyObject_CallOneArg(category, message);

if (message == NULL)

goto cleanup;

}

lineno_obj = PyLong_FromLong(lineno);

if (lineno_obj == NULL)

goto cleanup;

if (source == Py_None) {

source = NULL;

}

/* Create key. */

key = PyTuple_Pack(3, text, category, lineno_obj);

if (key == NULL)

goto cleanup;

if ((registry != NULL) && (registry != Py_None)) {

rc = already_warned(interp, registry, key, 0);

if (rc == -1)

goto cleanup;

else if (rc == 1)

goto return_none;

/* Else this warning hasn't been generated before. */

}

action = get_filter(interp, category, text, lineno, module, &item);

if (action == NULL)

goto cleanup;

if (_PyUnicode_EqualToASCIIString(action, "error")) {

PyErr_SetObject(category, message);

goto cleanup;

}

if (_PyUnicode_EqualToASCIIString(action, "ignore")) {

goto return_none;

}

/* Store in the registry that we've been here, *except* when the action

rc = 0;

if (!_PyUnicode_EqualToASCIIString(action, "always")) {

if (registry != NULL && registry != Py_None &&

PyDict_SetItem(registry, key, Py_True) < 0)

{

goto cleanup;

}

if (_PyUnicode_EqualToASCIIString(action, "once")) {

if (registry == NULL || registry == Py_None) {

registry = get_once_registry(interp);

if (registry == NULL)

goto cleanup;

}

/* WarningsState.once_registry[(text, category)] = 1 */

rc = update_registry(interp, registry, text, category, 0);

}

else if (_PyUnicode_EqualToASCIIString(action, "module")) {

/* registry[(text, category, 0)] = 1 */

if (registry != NULL && registry != Py_None)

rc = update_registry(interp, registry, text, category, 0);

}

else if (!_PyUnicode_EqualToASCIIString(action, "default")) {

PyErr_Format(PyExc_RuntimeError,

"Unrecognized action (%R) in warnings.filters:\n %R",

action, item);

goto cleanup;

}

}

if (rc == 1) /* Already warned for this module. */

goto return_none;

if (rc == 0) {

if (call_show_warning(tstate, category, text, message, filename,

lineno, lineno_obj, sourceline, source) < 0)

goto cleanup;

}

else /* if (rc == -1) */

goto cleanup;

return_none:

result = Py_NewRef(Py_None);

cleanup:

Py_XDECREF(item);

Py_XDECREF(key);

Py_XDECREF(text);

Py_XDECREF(lineno_obj);

Py_DECREF(module);

Py_XDECREF(message);

return result; /* Py_None or NULL. */

}

static PyObject *

get_frame_filename(PyFrameObject *frame)

{

PyCodeObject *code = PyFrame_GetCode(frame);

PyObject *filename = code->co_filename;

Py_DECREF(code);

return filename;

}

static bool

is_internal_filename(PyObject *filename)

{

if (!PyUnicode_Check(filename)) {

return false;

}

int contains = PyUnicode_Contains(filename, &_Py_ID(importlib));

if (contains < 0) {

return false;

}

else if (contains > 0) {

contains = PyUnicode_Contains(filename, &_Py_ID(_bootstrap));

if (contains < 0) {

return false;

}

else if (contains > 0) {

return true;

}

}

return false;

}

static bool

is_filename_to_skip(PyObject *filename, PyTupleObject *skip_file_prefixes)

{

if (skip_file_prefixes) {

if (!PyUnicode_Check(filename)) {

return false;

}

Py_ssize_t prefixes = PyTuple_GET_SIZE(skip_file_prefixes);

for (Py_ssize_t idx = 0; idx < prefixes; ++idx)

{

PyObject *prefix = PyTuple_GET_ITEM(skip_file_prefixes, idx);

Py_ssize_t found = PyUnicode_Tailmatch(filename, prefix, 0, -1, -1);

if (found == 1) {

return true;

}

if (found < 0) {

return false;

}

}

}

return false;

}

static bool

is_internal_frame(PyFrameObject *frame)

{

if (frame == NULL) {

return false;

}

PyObject *filename = get_frame_filename(frame);

if (filename == NULL) {

return false;

}

return is_internal_filename(filename);

}

static PyFrameObject *

next_external_frame(PyFrameObject *frame, PyTupleObject *skip_file_prefixes)

{

PyObject *frame_filename;

do {

PyFrameObject *back = PyFrame_GetBack(frame);

Py_SETREF(frame, back);

} while (frame != NULL && (frame_filename = get_frame_filename(frame)) &&

(is_internal_filename(frame_filename) ||

is_filename_to_skip(frame_filename, skip_file_prefixes)));

return frame;

}

static int

setup_context(Py_ssize_t stack_level,

PyTupleObject *skip_file_prefixes,

PyObject **filename, int *lineno,

PyObject **module, PyObject **registry)

{

PyObject *globals;

/* Setup globals, filename and lineno. */

PyThreadState *tstate = get_current_tstate();

if (tstate == NULL) {

return 0;

}

if (skip_file_prefixes) {

/* Type check our data structure up front. Later code that uses it

Py_ssize_t prefixes = PyTuple_GET_SIZE(skip_file_prefixes);

for (Py_ssize_t idx = 0; idx < prefixes; ++idx)

{

PyObject *prefix = PyTuple_GET_ITEM(skip_file_prefixes, idx);

if (!PyUnicode_Check(prefix)) {

PyErr_Format(PyExc_TypeError,

"Found non-str '%s' in skip_file_prefixes.",

Py_TYPE(prefix)->tp_name);

return 0;

}

}

}

PyInterpreterState *interp = tstate->interp;

PyFrameObject *f = PyThreadState_GetFrame(tstate);

// Stack level comparisons to Python code is off by one as there is no

// warnings-related stack level to avoid.

if (stack_level <= 0 || is_internal_frame(f)) {

while (--stack_level > 0 && f != NULL) {

PyFrameObject *back = PyFrame_GetBack(f);

Py_SETREF(f, back);

}

}

else {

while (--stack_level > 0 && f != NULL) {

f = next_external_frame(f, skip_file_prefixes);

}

}

if (f == NULL) {

globals = interp->sysdict;

*filename = PyUnicode_FromString("sys");

*lineno = 1;

}

else {

globals = f->f_frame->f_globals;

*filename = Py_NewRef(f->f_frame->f_code->co_filename);

*lineno = PyFrame_GetLineNumber(f);

Py_DECREF(f);

}

*module = NULL;

/* Setup registry. */

assert(globals != NULL);

assert(PyDict_Check(globals));

*registry = _PyDict_GetItemWithError(globals, &_Py_ID(__warningregistry__));

if (*registry == NULL) {

int rc;

if (_PyErr_Occurred(tstate)) {

goto handle_error;

}

*registry = PyDict_New();

if (*registry == NULL)

goto handle_error;

rc = PyDict_SetItem(globals, &_Py_ID(__warningregistry__), *registry);

if (rc < 0)

goto handle_error;

}

else

Py_INCREF(*registry);

/* Setup module. */

*module = _PyDict_GetItemWithError(globals, &_Py_ID(__name__));

if (*module == Py_None || (*module != NULL && PyUnicode_Check(*module))) {

Py_INCREF(*module);

}

else if (_PyErr_Occurred(tstate)) {

goto handle_error;

}

else {

*module = PyUnicode_FromString("<string>");

if (*module == NULL)

goto handle_error;

}

return 1;

handle_error:

Py_XDECREF(*registry);

Py_XDECREF(*module);

Py_DECREF(*filename);

return 0;

}

static PyObject *

get_category(PyObject *message, PyObject *category)

{

int rc;

/* Get category. */

rc = PyObject_IsInstance(message, PyExc_Warning);

if (rc == -1)

return NULL;

if (rc == 1)

category = (PyObject*)Py_TYPE(message);

else if (category == NULL || category == Py_None)

category = PyExc_UserWarning;

/* Validate category. */

rc = PyObject_IsSubclass(category, PyExc_Warning);

/* category is not a subclass of PyExc_Warning or

if (rc == -1 || rc == 0) {

PyErr_Format(PyExc_TypeError,

"category must be a Warning subclass, not '%s'",

Py_TYPE(category)->tp_name);

return NULL;

}

return category;

}

static PyObject *

do_warn(PyObject *message, PyObject *category, Py_ssize_t stack_level,

PyObject *source, PyTupleObject *skip_file_prefixes)

{

PyObject *filename, *module, *registry, *res;

int lineno;

PyThreadState *tstate = get_current_tstate();

if (tstate == NULL) {

return NULL;

}

if (!setup_context(stack_level, skip_file_prefixes,

&filename, &lineno, &module, &registry))

return NULL;