intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 1430 insertions, 0 deletions

diff --git a/contrib/tools/python3/src/Python/_warnings.c b/contrib/tools/python3/src/Python/_warnings.c
new file mode 100644
index 0000000000..91a78fe72b
--- /dev/null
+++ b/contrib/tools/python3/src/Python/_warnings.c
@@ -0,0 +1,1430 @@
+#include "Python.h"
+#include "pycore_initconfig.h"
+#include "pycore_interp.h"        // PyInterpreterState.warnings
+#include "pycore_pyerrors.h"
+#include "pycore_pystate.h"       // _PyThreadState_GET()
+#include "frameobject.h"          // PyFrame_GetBack()
+#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.");
+
+_Py_IDENTIFIER(stderr);
+#ifndef Py_DEBUG
+_Py_IDENTIFIER(default);
+_Py_IDENTIFIER(ignore);
+#endif
+
+
+/*************************************************************************/
+
+typedef struct _warnings_runtime_state WarningsState;
+
+/* Forward declaration of the _warnings module definition. */
+static struct PyModuleDef warningsmodule;
+
+_Py_IDENTIFIER(__name__);
+
+/* Given a module object, get its per-module state. */
+static WarningsState *
+warnings_get_state(void)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+    if (tstate == NULL) {
+        _PyErr_SetString(tstate, PyExc_RuntimeError,
+                          "warnings_get_state: could not identify "
+                          "current interpreter");
+        return NULL;
+    }
+    return &tstate->interp->warnings;
+}
+
+/* Clear the given warnings module state. */
+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, _Py_Identifier *id, const char *modname)
+{
+    PyObject *modname_obj = NULL;
+    PyObject *action_str = _PyUnicode_FromId(id);
+    if (action_str == NULL) {
+        return 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_None;
+        Py_INCREF(modname_obj);
+    }
+
+    /* This assumes the line number is zero for now. */
+    PyObject *filter = PyTuple_Pack(5, action_str, Py_None,
+                                    category, modname_obj, _PyLong_Zero);
+    Py_DECREF(modname_obj);
+    return filter;
+}
+#endif
+
+static PyObject *
+init_filters(void)
+{
+#ifdef Py_DEBUG
+    /* Py_DEBUG builds show all warnings by default */
+    return PyList_New(0);
+#else
+    /* 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. */
+    PyList_SET_ITEM(filters, pos++,
+                    create_filter(PyExc_DeprecationWarning, &PyId_default, "__main__"));
+    PyList_SET_ITEM(filters, pos++,
+                    create_filter(PyExc_DeprecationWarning, &PyId_ignore, NULL));
+    PyList_SET_ITEM(filters, pos++,
+                    create_filter(PyExc_PendingDeprecationWarning, &PyId_ignore, NULL));
+    PyList_SET_ITEM(filters, pos++,
+                    create_filter(PyExc_ImportWarning, &PyId_ignore, NULL));
+    PyList_SET_ITEM(filters, pos++,
+                    create_filter(PyExc_ResourceWarning, &PyId_ignore, NULL));
+
+    for (size_t x = 0; x < pos; x++) {
+        if (PyList_GET_ITEM(filters, x) == NULL) {
+            Py_DECREF(filters);
+            return NULL;
+        }
+    }
+    return filters;
+#endif
+}
+
+/* Initialize the given warnings module state. */
+static int
+warnings_init_state(WarningsState *st)
+{
+    if (st->filters == NULL) {
+        st->filters = init_filters();
+        if (st->filters == NULL) {
+            goto error;
+        }
+    }
+
+    if (st->once_registry == NULL) {
+        st->once_registry = PyDict_New();
+        if (st->once_registry == NULL) {
+            goto error;
+        }
+    }
+
+    if (st->default_action == NULL) {
+        st->default_action = PyUnicode_FromString("default");
+        if (st->default_action == NULL) {
+            goto error;
+        }
+    }
+
+    st->filters_version = 0;
+
+    return 0;
+
+error:
+    warnings_clear_state(st);
+    return -1;
+}
+
+
+/*************************************************************************/
+
+static int
+check_matched(PyObject *obj, PyObject *arg)
+{
+    PyObject *result;
+    _Py_IDENTIFIER(match);
+    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_CallMethodIdOneArg(obj, &PyId_match, arg);
+    if (result == NULL)
+        return -1;
+
+    rc = PyObject_IsTrue(result);
+    Py_DECREF(result);
+    return rc;
+}
+
+/*
+   Returns a new reference.
+   A NULL return value can mean false or an error.
+*/
+static PyObject *
+get_warnings_attr(_Py_Identifier *attr_id, int try_import)
+{
+    PyObject *warnings_str;
+    PyObject *warnings_module, *obj;
+    _Py_IDENTIFIER(warnings);
+
+    warnings_str = _PyUnicode_FromId(&PyId_warnings);
+    if (warnings_str == NULL) {
+        return NULL;
+    }
+
+    /* don't try to import after the start of the Python finallization */
+    if (try_import && !_Py_IsFinalizing()) {
+        warnings_module = PyImport_Import(warnings_str);
+        if (warnings_module == NULL) {
+            /* Fallback to the C implementation if we cannot get
+               the Python implementation */
+            if (PyErr_ExceptionMatches(PyExc_ImportError)) {
+                PyErr_Clear();
+            }
+            return NULL;
+        }
+    }
+    else {
+        /* if we're so late into Python finalization that the module dict is
+           gone, then we can't even use PyImport_GetModule without triggering
+           an interpreter abort.
+        */
+        if (!_PyInterpreterState_GET()->modules) {
+            return NULL;
+        }
+        warnings_module = PyImport_GetModule(warnings_str);
+        if (warnings_module == NULL)
+            return NULL;
+    }
+
+    (void)_PyObject_LookupAttrId(warnings_module, attr_id, &obj);
+    Py_DECREF(warnings_module);
+    return obj;
+}
+
+
+static PyObject *
+get_once_registry(WarningsState *st)
+{
+    PyObject *registry;
+    _Py_IDENTIFIER(onceregistry);
+
+    registry = get_warnings_attr(&PyId_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(WarningsState *st)
+{
+    PyObject *default_action;
+    _Py_IDENTIFIER(defaultaction);
+
+    default_action = get_warnings_attr(&PyId_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;
+}
+
+
+/* The item is a new reference. */
+static PyObject*
+get_filter(PyObject *category, PyObject *text, Py_ssize_t lineno,
+           PyObject *module, PyObject **item)
+{
+    PyObject *action;
+    Py_ssize_t i;
+    PyObject *warnings_filters;
+    _Py_IDENTIFIER(filters);
+    WarningsState *st = warnings_get_state();
+    if (st == NULL) {
+        return NULL;
+    }
+
+    warnings_filters = get_warnings_attr(&PyId_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(msg, text);
+        if (good_msg == -1) {
+            Py_DECREF(tmp_item);
+            return NULL;
+        }
+
+        good_mod = check_matched(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(st);
+    if (action != NULL) {
+        Py_INCREF(Py_None);
+        *item = Py_None;
+        return action;
+    }
+
+    return NULL;
+}
+
+
+static int
+already_warned(PyObject *registry, PyObject *key, int should_set)
+{
+    PyObject *version_obj, *already_warned;
+    _Py_IDENTIFIER(version);
+
+    if (key == NULL)
+        return -1;
+
+    WarningsState *st = warnings_get_state();
+    if (st == NULL) {
+        return -1;
+    }
+    version_obj = _PyDict_GetItemIdWithError(registry, &PyId_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_SetItemId(registry, &PyId_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;
+}
+
+/* New reference. */
+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 = filename;
+        Py_INCREF(module);
+    }
+    return module;
+}
+
+static int
+update_registry(PyObject *registry, PyObject *text, PyObject *category,
+                int add_zero)
+{
+    PyObject *altkey;
+    int rc;
+
+    if (add_zero)
+        altkey = PyTuple_Pack(3, text, category, _PyLong_Zero);
+    else
+        altkey = PyTuple_Pack(2, text, category);
+
+    rc = already_warned(registry, altkey, 1);
+    Py_XDECREF(altkey);
+    return rc;
+}
+
+static void
+show_warning(PyObject *filename, int lineno, PyObject *text,
+             PyObject *category, PyObject *sourceline)
+{
+    PyObject *f_stderr;
+    PyObject *name;
+    char lineno_str[128];
+
+    PyOS_snprintf(lineno_str, sizeof(lineno_str), ":%d: ", lineno);
+
+    name = _PyObject_GetAttrId(category, &PyId___name__);
+    if (name == NULL) {
+        goto error;
+    }
+
+    f_stderr = _PySys_GetObjectId(&PyId_stderr);
+    if (f_stderr == NULL) {
+        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);
+    }
+
+error:
+    Py_XDECREF(name);
+    PyErr_Clear();
+}
+
+static int
+call_show_warning(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;
+    _Py_IDENTIFIER(_showwarnmsg);
+    _Py_IDENTIFIER(WarningMessage);
+
+    /* If the source parameter is set, try to get the Python implementation.
+       The Python implementation is able to log the traceback where the source
+       was allocated, whereas the C implementation doesn't. */
+    show_fn = get_warnings_attr(&PyId__showwarnmsg, source != NULL);
+    if (show_fn == NULL) {
+        if (PyErr_Occurred())
+            return -1;
+        show_warning(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(&PyId_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(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;
+
+    /* module can be None if a warning is emitted late during Python shutdown.
+       In this case, the Python warnings module was probably unloaded, filters
+       are no more available to choose as action. It is safer to ignore the
+       warning and do nothing. */
+    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(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(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
+       is "always". */
+    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) {
+                WarningsState *st = warnings_get_state();
+                if (st == NULL) {
+                    goto cleanup;
+                }
+                registry = get_once_registry(st);
+                if (registry == NULL)
+                    goto cleanup;
+            }
+            /* WarningsState.once_registry[(text, category)] = 1 */
+            rc = update_registry(registry, text, category, 0);
+        }
+        else if (_PyUnicode_EqualToASCIIString(action, "module")) {
+            /* registry[(text, category, 0)] = 1 */
+            if (registry != NULL && registry != Py_None)
+                rc = update_registry(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(category, text, message, filename, lineno,
+                              lineno_obj, sourceline, source) < 0)
+            goto cleanup;
+    }
+    else /* if (rc == -1) */
+        goto cleanup;
+
+ return_none:
+    result = Py_None;
+    Py_INCREF(result);
+
+ 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 int
+is_internal_frame(PyFrameObject *frame)
+{
+    static PyObject *importlib_string = NULL;
+    static PyObject *bootstrap_string = NULL;
+    int contains;
+
+    if (importlib_string == NULL) {
+        importlib_string = PyUnicode_FromString("importlib");
+        if (importlib_string == NULL) {
+            return 0;
+        }
+
+        bootstrap_string = PyUnicode_FromString("_bootstrap");
+        if (bootstrap_string == NULL) {
+            Py_DECREF(importlib_string);
+            return 0;
+        }
+        Py_INCREF(importlib_string);
+        Py_INCREF(bootstrap_string);
+    }
+
+    if (frame == NULL) {
+        return 0;
+    }
+
+    PyCodeObject *code = PyFrame_GetCode(frame);
+    PyObject *filename = code->co_filename;
+    Py_DECREF(code);
+
+    if (filename == NULL) {
+        return 0;
+    }
+    if (!PyUnicode_Check(filename)) {
+        return 0;
+    }
+
+    contains = PyUnicode_Contains(filename, importlib_string);
+    if (contains < 0) {
+        return 0;
+    }
+    else if (contains > 0) {
+        contains = PyUnicode_Contains(filename, bootstrap_string);
+        if (contains < 0) {
+            return 0;
+        }
+        else if (contains > 0) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+static PyFrameObject *
+next_external_frame(PyFrameObject *frame)
+{
+    do {
+        PyFrameObject *back = PyFrame_GetBack(frame);
+        Py_DECREF(frame);
+        frame = back;
+    } while (frame != NULL && is_internal_frame(frame));
+
+    return frame;
+}
+
+/* filename, module, and registry are new refs, globals is borrowed */
+/* Returns 0 on error (no new refs), 1 on success */
+static int
+setup_context(Py_ssize_t stack_level, PyObject **filename, int *lineno,
+              PyObject **module, PyObject **registry)
+{
+    _Py_IDENTIFIER(__warningregistry__);
+    PyObject *globals;
+
+    /* Setup globals, filename and lineno. */
+    PyThreadState *tstate = _PyThreadState_GET();
+    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_DECREF(f);
+            f = back;
+        }
+    }
+    else {
+        while (--stack_level > 0 && f != NULL) {
+            f = next_external_frame(f);
+        }
+    }
+
+    if (f == NULL) {
+        globals = _PyInterpreterState_GET()->sysdict;
+        *filename = PyUnicode_FromString("sys");
+        *lineno = 1;
+    }
+    else {
+        globals = f->f_globals;
+        PyCodeObject *code = PyFrame_GetCode(f);
+        *filename = code->co_filename;
+        Py_DECREF(code);
+        Py_INCREF(*filename);
+        *lineno = PyFrame_GetLineNumber(f);
+        Py_DECREF(f);
+    }
+
+    *module = NULL;
+
+    /* Setup registry. */
+    assert(globals != NULL);
+    assert(PyDict_Check(globals));
+    *registry = _PyDict_GetItemIdWithError(globals, &PyId___warningregistry__);
+    if (*registry == NULL) {
+        int rc;
+
+        if (_PyErr_Occurred(tstate)) {
+            goto handle_error;
+        }
+        *registry = PyDict_New();
+        if (*registry == NULL)
+            goto handle_error;
+
+         rc = _PyDict_SetItemId(globals, &PyId___warningregistry__, *registry);
+         if (rc < 0)
+            goto handle_error;
+    }
+    else
+        Py_INCREF(*registry);
+
+    /* Setup module. */
+    *module = _PyDict_GetItemIdWithError(globals, &PyId___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
+       PyObject_IsSubclass raised an error */
+    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)
+{
+    PyObject *filename, *module, *registry, *res;
+    int lineno;
+
+    if (!setup_context(stack_level, &filename, &lineno, &module, &registry))
+        return NULL;
+
+    res = warn_explicit(category, message, filename, lineno, module, registry,
+                        NULL, source);
+    Py_DECREF(filename);
+    Py_DECREF(registry);
+    Py_DECREF(module);
+    return res;
+}
+
+/*[clinic input]
+warn as warnings_warn
+
+    message: object
+    category: object = None
+    stacklevel: Py_ssize_t = 1
+    source: object = None
+
+Issue a warning, or maybe ignore it or raise an exception.
+[clinic start generated code]*/
+
+static PyObject *
+warnings_warn_impl(PyObject *module, PyObject *message, PyObject *category,
+                   Py_ssize_t stacklevel, PyObject *source)
+/*[clinic end generated code: output=31ed5ab7d8d760b2 input=bfdf5cf99f6c4edd]*/
+{
+    category = get_category(message, category);
+    if (category == NULL)
+        return NULL;
+    return do_warn(message, category, stacklevel, source);
+}
+
+static PyObject *
+get_source_line(PyObject *module_globals, int lineno)
+{
+    _Py_IDENTIFIER(get_source);
+    _Py_IDENTIFIER(__loader__);
+    PyObject *loader;
+    PyObject *module_name;
+    PyObject *get_source;
+    PyObject *source;
+    PyObject *source_list;
+    PyObject *source_line;
+
+    /* Check/get the requisite pieces needed for the loader. */
+    loader = _PyDict_GetItemIdWithError(module_globals, &PyId___loader__);
+    if (loader == NULL) {
+        return NULL;
+    }
+    Py_INCREF(loader);
+    module_name = _PyDict_GetItemIdWithError(module_globals, &PyId___name__);
+    if (!module_name) {
+        Py_DECREF(loader);
+        return NULL;
+    }
+    Py_INCREF(module_name);
+
+    /* Make sure the loader implements the optional get_source() method. */
+    (void)_PyObject_LookupAttrId(loader, &PyId_get_source, &get_source);
+    Py_DECREF(loader);
+    if (!get_source) {
+        Py_DECREF(module_name);
+        return NULL;
+    }
+    /* Call get_source() to get the source code. */
+    source = PyObject_CallOneArg(get_source, module_name);
+    Py_DECREF(get_source);
+    Py_DECREF(module_name);
+    if (!source) {
+        return NULL;
+    }
+    if (source == Py_None) {
+        Py_DECREF(source);
+        return NULL;
+    }
+
+    /* Split the source into lines. */
+    source_list = PyUnicode_Splitlines(source, 0);
+    Py_DECREF(source);
+    if (!source_list) {
+        return NULL;
+    }
+
+    /* Get the source line. */
+    source_line = PyList_GetItem(source_list, lineno-1);
+    Py_XINCREF(source_line);
+    Py_DECREF(source_list);
+    return source_line;
+}
+
+static PyObject *
+warnings_warn_explicit(PyObject *self, PyObject *args, PyObject *kwds)
+{
+    static char *kwd_list[] = {"message", "category", "filename", "lineno",
+                                "module", "registry", "module_globals",
+                                "source", 0};
+    PyObject *message;
+    PyObject *category;
+    PyObject *filename;
+    int lineno;
+    PyObject *module = NULL;
+    PyObject *registry = NULL;
+    PyObject *module_globals = NULL;
+    PyObject *sourceobj = NULL;
+    PyObject *source_line = NULL;
+    PyObject *returned;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOUi|OOOO:warn_explicit",
+                kwd_list, &message, &category, &filename, &lineno, &module,
+                &registry, &module_globals, &sourceobj))
+        return NULL;
+
+    if (module_globals && module_globals != Py_None) {
+        if (!PyDict_Check(module_globals)) {
+            PyErr_Format(PyExc_TypeError,
+                         "module_globals must be a dict, not '%.200s'",
+                         Py_TYPE(module_globals)->tp_name);
+            return NULL;
+        }
+
+        source_line = get_source_line(module_globals, lineno);
+        if (source_line == NULL && PyErr_Occurred()) {
+            return NULL;
+        }
+    }
+    returned = warn_explicit(category, message, filename, lineno, module,
+                             registry, source_line, sourceobj);
+    Py_XDECREF(source_line);
+    return returned;
+}
+
+static PyObject *
+warnings_filters_mutated(PyObject *self, PyObject *args)
+{
+    WarningsState *st = warnings_get_state();
+    if (st == NULL) {
+        return NULL;
+    }
+    st->filters_version++;
+    Py_RETURN_NONE;
+}
+
+
+/* Function to issue a warning message; may raise an exception. */
+
+static int
+warn_unicode(PyObject *category, PyObject *message,
+             Py_ssize_t stack_level, PyObject *source)
+{
+    PyObject *res;
+
+    if (category == NULL)
+        category = PyExc_RuntimeWarning;
+
+    res = do_warn(message, category, stack_level, source);
+    if (res == NULL)
+        return -1;
+    Py_DECREF(res);
+
+    return 0;
+}
+
+static int
+_PyErr_WarnFormatV(PyObject *source,
+                   PyObject *category, Py_ssize_t stack_level,
+                   const char *format, va_list vargs)
+{
+    PyObject *message;
+    int res;
+
+    message = PyUnicode_FromFormatV(format, vargs);
+    if (message == NULL)
+        return -1;
+
+    res = warn_unicode(category, message, stack_level, source);
+    Py_DECREF(message);
+    return res;
+}
+
+int
+PyErr_WarnFormat(PyObject *category, Py_ssize_t stack_level,
+                 const char *format, ...)
+{
+    int res;
+    va_list vargs;
+
+#ifdef HAVE_STDARG_PROTOTYPES
+    va_start(vargs, format);
+#else
+    va_start(vargs);
+#endif
+    res = _PyErr_WarnFormatV(NULL, category, stack_level, format, vargs);
+    va_end(vargs);
+    return res;
+}
+
+static int
+_PyErr_WarnFormat(PyObject *source, PyObject *category, Py_ssize_t stack_level,
+                  const char *format, ...)
+{
+    int res;
+    va_list vargs;
+
+#ifdef HAVE_STDARG_PROTOTYPES
+    va_start(vargs, format);
+#else
+    va_start(vargs);
+#endif
+    res = _PyErr_WarnFormatV(source, category, stack_level, format, vargs);
+    va_end(vargs);
+    return res;
+}
+
+int
+PyErr_ResourceWarning(PyObject *source, Py_ssize_t stack_level,
+                      const char *format, ...)
+{
+    int res;
+    va_list vargs;
+
+#ifdef HAVE_STDARG_PROTOTYPES
+    va_start(vargs, format);
+#else
+    va_start(vargs);
+#endif
+    res = _PyErr_WarnFormatV(source, PyExc_ResourceWarning,
+                             stack_level, format, vargs);
+    va_end(vargs);
+    return res;
+}
+
+
+int
+PyErr_WarnEx(PyObject *category, const char *text, Py_ssize_t stack_level)
+{
+    int ret;
+    PyObject *message = PyUnicode_FromString(text);
+    if (message == NULL)
+        return -1;
+    ret = warn_unicode(category, message, stack_level, NULL);
+    Py_DECREF(message);
+    return ret;
+}
+
+/* PyErr_Warn is only for backwards compatibility and will be removed.
+   Use PyErr_WarnEx instead. */
+
+#undef PyErr_Warn
+
+int
+PyErr_Warn(PyObject *category, const char *text)
+{
+    return PyErr_WarnEx(category, text, 1);
+}
+
+/* Warning with explicit origin */
+int
+PyErr_WarnExplicitObject(PyObject *category, PyObject *message,
+                         PyObject *filename, int lineno,
+                         PyObject *module, PyObject *registry)
+{
+    PyObject *res;
+    if (category == NULL)
+        category = PyExc_RuntimeWarning;
+    res = warn_explicit(category, message, filename, lineno,
+                        module, registry, NULL, NULL);
+    if (res == NULL)
+        return -1;
+    Py_DECREF(res);
+    return 0;
+}
+
+int
+PyErr_WarnExplicit(PyObject *category, const char *text,
+                   const char *filename_str, int lineno,
+                   const char *module_str, PyObject *registry)
+{
+    PyObject *message = PyUnicode_FromString(text);
+    PyObject *filename = PyUnicode_DecodeFSDefault(filename_str);
+    PyObject *module = NULL;
+    int ret = -1;
+
+    if (message == NULL || filename == NULL)
+        goto exit;
+    if (module_str != NULL) {
+        module = PyUnicode_FromString(module_str);
+        if (module == NULL)
+            goto exit;
+    }
+
+    ret = PyErr_WarnExplicitObject(category, message, filename, lineno,
+                                   module, registry);
+
+ exit:
+    Py_XDECREF(message);
+    Py_XDECREF(module);
+    Py_XDECREF(filename);
+    return ret;
+}
+
+int
+PyErr_WarnExplicitFormat(PyObject *category,
+                         const char *filename_str, int lineno,
+                         const char *module_str, PyObject *registry,
+                         const char *format, ...)
+{
+    PyObject *message;
+    PyObject *module = NULL;
+    PyObject *filename = PyUnicode_DecodeFSDefault(filename_str);
+    int ret = -1;
+    va_list vargs;
+
+    if (filename == NULL)
+        goto exit;
+    if (module_str != NULL) {
+        module = PyUnicode_FromString(module_str);
+        if (module == NULL)
+            goto exit;
+    }
+
+#ifdef HAVE_STDARG_PROTOTYPES
+    va_start(vargs, format);
+#else
+    va_start(vargs);
+#endif
+    message = PyUnicode_FromFormatV(format, vargs);
+    if (message != NULL) {
+        PyObject *res;
+        res = warn_explicit(category, message, filename, lineno,
+                            module, registry, NULL, NULL);
+        Py_DECREF(message);
+        if (res != NULL) {
+            Py_DECREF(res);
+            ret = 0;
+        }
+    }
+    va_end(vargs);
+exit:
+    Py_XDECREF(module);
+    Py_XDECREF(filename);
+    return ret;
+}
+
+void
+_PyErr_WarnUnawaitedCoroutine(PyObject *coro)
+{
+    /* First, we attempt to funnel the warning through
+       warnings._warn_unawaited_coroutine.
+
+       This could raise an exception, due to:
+       - a bug
+       - some kind of shutdown-related brokenness
+       - succeeding, but with an "error" warning filter installed, so the
+         warning is converted into a RuntimeWarning exception
+
+       In the first two cases, we want to print the error (so we know what it
+       is!), and then print a warning directly as a fallback. In the last
+       case, we want to print the error (since it's the warning!), but *not*
+       do a fallback. And after we print the error we can't check for what
+       type of error it was (because PyErr_WriteUnraisable clears it), so we
+       need a flag to keep track.
+
+       Since this is called from __del__ context, it's careful to never raise
+       an exception.
+    */
+    _Py_IDENTIFIER(_warn_unawaited_coroutine);
+    int warned = 0;
+    PyObject *fn = get_warnings_attr(&PyId__warn_unawaited_coroutine, 1);
+    if (fn) {
+        PyObject *res = PyObject_CallOneArg(fn, coro);
+        Py_DECREF(fn);
+        if (res || PyErr_ExceptionMatches(PyExc_RuntimeWarning)) {
+            warned = 1;
+        }
+        Py_XDECREF(res);
+    }
+
+    if (PyErr_Occurred()) {
+        PyErr_WriteUnraisable(coro);
+    }
+    if (!warned) {
+        if (_PyErr_WarnFormat(coro, PyExc_RuntimeWarning, 1,
+                              "coroutine '%S' was never awaited",
+                              ((PyCoroObject *)coro)->cr_qualname) < 0)
+        {
+            PyErr_WriteUnraisable(coro);
+        }
+    }
+}
+
+PyDoc_STRVAR(warn_explicit_doc,
+"Low-level interface to warnings functionality.");
+
+static PyMethodDef warnings_functions[] = {
+    WARNINGS_WARN_METHODDEF
+    {"warn_explicit", (PyCFunction)(void(*)(void))warnings_warn_explicit,
+        METH_VARARGS | METH_KEYWORDS, warn_explicit_doc},
+    {"_filters_mutated", (PyCFunction)warnings_filters_mutated, METH_NOARGS,
+        NULL},
+    /* XXX(brett.cannon): add showwarning? */
+    /* XXX(brett.cannon): Reasonable to add formatwarning? */
+    {NULL, NULL}                /* sentinel */
+};
+
+
+static struct PyModuleDef warningsmodule = {
+        PyModuleDef_HEAD_INIT,
+        MODULE_NAME,            /* m_name */
+        warnings__doc__,        /* m_doc */
+        0,                      /* m_size */
+        warnings_functions,     /* m_methods */
+        NULL,                   /* m_reload */
+        NULL,                   /* m_traverse */
+        NULL,                   /* m_clear */
+        NULL                    /* m_free */
+};
+
+
+PyStatus
+_PyWarnings_InitState(PyThreadState *tstate)
+{
+    if (warnings_init_state(&tstate->interp->warnings) < 0) {
+        return _PyStatus_ERR("can't initialize warnings");
+    }
+    return _PyStatus_OK();
+}
+
+
+PyMODINIT_FUNC
+_PyWarnings_Init(void)
+{
+    PyObject *m;
+
+    m = PyModule_Create(&warningsmodule);
+    if (m == NULL) {
+        return NULL;
+    }
+
+    WarningsState *st = warnings_get_state();
+    if (st == NULL) {
+        goto error;
+    }
+    if (warnings_init_state(st) < 0) {
+        goto error;
+    }
+
+    Py_INCREF(st->filters);
+    if (PyModule_AddObject(m, "filters", st->filters) < 0) {
+        goto error;
+    }
+
+    Py_INCREF(st->once_registry);
+    if (PyModule_AddObject(m, "_onceregistry", st->once_registry) < 0) {
+        goto error;
+    }
+
+    Py_INCREF(st->default_action);
+    if (PyModule_AddObject(m, "_defaultaction", st->default_action) < 0) {
+        goto error;
+    }
+
+    return m;
+
+error:
+    if (st != NULL) {
+        warnings_clear_state(st);
+    }
+    Py_DECREF(m);
+    return NULL;
+}
+
+// We need this to ensure that warnings still work until late in finalization.
+void
+_PyWarnings_Fini(PyInterpreterState *interp)
+{
+    warnings_clear_state(&interp->warnings);
+}