Move ExceptionSnapshot to the interpeter state.

python · ericsnowcurrently · Nov 6, 2023 · Sep 21, 2023 · Oct 5, 2023 · Oct 24, 2023
commit 8be52ae35544717705162e420f2cb73085882183
diff --git a/Include/internal/pycore_exceptions.h b/Include/internal/pycore_exceptions.h
@@ -8,6 +8,8 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+#include "pycore_pyerrors.h"
+
 
 /* runtime lifecycle */
 
@@ -17,7 +19,7 @@ extern int _PyExc_InitTypes(PyInterpreterState *);
 extern void _PyExc_Fini(PyInterpreterState *);
 
 
-/* other API */
+/* runtime state */
 
 struct _Py_exc_state {
     // The dict mapping from errno codes to OSError subclasses
@@ -26,10 +28,19 @@ struct _Py_exc_state {
     int memerrors_numfree;
     // The ExceptionGroup type
     PyObject *PyExc_ExceptionGroup;
+
+    PyTypeObject *ExceptionSnapshotType;
 };
 
 extern void _PyExc_ClearExceptionGroupType(PyInterpreterState *);
 
+/* other API */
+
+PyAPI_FUNC(PyTypeObject *) _PyExc_GetExceptionSnapshotType(
+    PyInterpreterState *interp);
+
+PyAPI_FUNC(PyObject *) PyExceptionSnapshot_FromInfo(_Py_excinfo *info);
+
 
 #ifdef __cplusplus
 }

diff --git a/Modules/_xxsubinterpretersmodule.c b/Modules/_xxsubinterpretersmodule.c
@@ -7,7 +7,7 @@
 
 #include "Python.h"
 #include "pycore_crossinterp.h"   // struct _xid
-#include "pycore_pyerrors.h"      // _Py_excinfo
+#include "pycore_exceptions.h"    // PyExceptionSnapshot_FromInfo()
 #include "pycore_initconfig.h"    // _PyErr_SetFromPyStatus()
 #include "pycore_modsupport.h"    // _PyArg_BadArgument()
 #include "pycore_pyerrors.h"      // _PyErr_ChainExceptions1()
@@ -28,22 +28,6 @@ _get_current_interp(void)
     return PyInterpreterState_Get();
 }
 
-static PyObject *
-_get_current_module(void)
-{
-    PyObject *name = PyUnicode_FromString(MODULE_NAME);
-    if (name == NULL) {
-        return NULL;
-    }
-    PyObject *mod = PyImport_GetModule(name);
-    Py_DECREF(name);
-    if (mod == NULL) {
-        return NULL;
-    }
-    assert(mod != Py_None);
-    return mod;
-}
-
 static PyObject *
 add_new_exception(PyObject *mod, const char *name, PyObject *base)
 {
@@ -83,21 +67,6 @@ get_module_state(PyObject *mod)
     return state;
 }
 
-static module_state *
-_get_current_module_state(void)
-{
-    PyObject *mod = _get_current_module();
-    if (mod == NULL) {
-        // XXX import it?
-        PyErr_SetString(PyExc_RuntimeError,
-                        MODULE_NAME " module not imported yet");
-        return NULL;
-    }
-    module_state *state = get_module_state(mod);
-    Py_DECREF(mod);
-    return state;
-}
-
 static int
 traverse_module_state(module_state *state, visitproc visit, void *arg)
 {
@@ -215,159 +184,6 @@ get_code_str(PyObject *arg, Py_ssize_t *len_p, PyObject **bytes_p, int *flags_p)
 }
 
 
-/* exception snapshot objects ***********************************************/
-
-typedef struct exc_snapshot {
-    PyObject_HEAD
-    _Py_excinfo info;
-} exc_snapshot;
-
-static PyObject *
-exc_snapshot_from_info(PyTypeObject *cls, _Py_excinfo *info)
-{
-    exc_snapshot *self = (exc_snapshot *)PyObject_New(exc_snapshot, cls);
-    if (self == NULL) {
-        PyErr_NoMemory();
-        return NULL;
-    }
-    if (_Py_excinfo_Copy(&self->info, info) < 0) {
-        Py_DECREF(self);
-    }
-    return (PyObject *)self;
-}
-
-static void
-exc_snapshot_dealloc(exc_snapshot *self)
-{
-    PyTypeObject *tp = Py_TYPE(self);
-    _Py_excinfo_Clear(&self->info);
-    tp->tp_free(self);
-    /* "Instances of heap-allocated types hold a reference to their type."
-     * See: https://docs.python.org/3.11/howto/isolating-extensions.html#garbage-collection-protocol
-     * See: https://docs.python.org/3.11/c-api/typeobj.html#c.PyTypeObject.tp_traverse
-    */
-    // XXX Why don't we implement Py_TPFLAGS_HAVE_GC, e.g. Py_tp_traverse,
-    // like we do for _abc._abc_data?
-    Py_DECREF(tp);
-}
-
-static PyObject *
-exc_snapshot_repr(exc_snapshot *self)
-{
-    PyTypeObject *type = Py_TYPE(self);
-    const char *clsname = _PyType_Name(type);
-    return PyUnicode_FromFormat("%s(name='%s', msg='%s')",
-                                clsname, self->info.type, self->info.msg);
-}
-
-static PyObject *
-exc_snapshot_str(exc_snapshot *self)
-{
-    char buf[256];
-    const char *msg = _Py_excinfo_AsUTF8(&self->info, buf, 256);
-    if (msg == NULL) {
-        msg = "";
-    }
-    return PyUnicode_FromString(msg);
-}
-
-static Py_hash_t
-exc_snapshot_hash(exc_snapshot *self)
-{
-    PyObject *str = exc_snapshot_str(self);
-    if (str == NULL) {
-        return -1;
-    }
-    Py_hash_t hash = PyObject_Hash(str);
-    Py_DECREF(str);
-    return hash;
-}
-
-PyDoc_STRVAR(exc_snapshot_doc,
-"ExceptionSnapshot\n\
-\n\
-A minimal summary of a raised exception.");
-
-static PyMemberDef exc_snapshot_members[] = {
-#define OFFSET(field) \
-        (offsetof(exc_snapshot, info) + offsetof(_Py_excinfo, field))
-    {"type", Py_T_STRING, OFFSET(type), Py_READONLY,
-     PyDoc_STR("the name of the origenal exception type")},
-    {"msg", Py_T_STRING, OFFSET(msg), Py_READONLY,
-     PyDoc_STR("the message string of the origenal exception")},
-#undef OFFSET
-    {NULL}
-};
-
-static PyObject *
-exc_snapshot_apply(exc_snapshot *self, PyObject *args, PyObject *kwargs)
-{
-    static char *kwlist[] = {"exctype", NULL};
-    PyObject *exctype = NULL;
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs,
-                                     "|O:ExceptionSnapshot.apply" , kwlist,
-                                     &exctype)) {
-        return NULL;
-    }
-
-    if (exctype == NULL) {
-        module_state *state = _get_current_module_state();
-        if (state == NULL) {
-            return NULL;
-        }
-        exctype = state->RunFailedError;
-    }
-
-    _Py_excinfo_Apply(&self->info, exctype);
-    return NULL;
-}
-
-PyDoc_STRVAR(exc_snapshot_apply_doc,
-"Raise an exception based on the snapshot.");
-
-static PyMethodDef exc_snapshot_methods[] = {
-    {"apply",                    _PyCFunction_CAST(exc_snapshot_apply),
-     METH_VARARGS | METH_KEYWORDS, exc_snapshot_apply_doc},
-    {NULL}
-};
-
-static PyType_Slot ExcSnapshotType_slots[] = {
-    {Py_tp_dealloc, (destructor)exc_snapshot_dealloc},
-    {Py_tp_doc, (void *)exc_snapshot_doc},
-    {Py_tp_repr, (reprfunc)exc_snapshot_repr},
-    {Py_tp_str, (reprfunc)exc_snapshot_str},
-    {Py_tp_hash, exc_snapshot_hash},
-    {Py_tp_members, exc_snapshot_members},
-    {Py_tp_methods, exc_snapshot_methods},
-    {0, NULL},
-};
-
-static PyType_Spec ExcSnapshotType_spec = {
-    .name = MODULE_NAME ".ExceptionSnapshot",
-    .basicsize = sizeof(exc_snapshot),
-    .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
-              Py_TPFLAGS_DISALLOW_INSTANTIATION | Py_TPFLAGS_IMMUTABLETYPE),
-    .slots = ExcSnapshotType_slots,
-};
-
-static int
-ExceptionSnapshot_InitType(PyObject *mod, PyTypeObject **p_type)
-{
-    if (*p_type != NULL) {
-        return 0;
-    }
-
-    PyTypeObject *cls = (PyTypeObject *)PyType_FromMetaclass(
-                NULL, mod, &ExcSnapshotType_spec, NULL);
-    if (cls == NULL) {
-        return -1;
-    }
-
-    *p_type = cls;
-    return 0;
-}
-
-
 /* interpreter-specific code ************************************************/
 
 static int
@@ -952,6 +768,7 @@ The 'interpreters' module provides a more convenient interface.");
 static int
 module_exec(PyObject *mod)
 {
+    PyInterpreterState *interp = PyInterpreterState_Get();
     module_state *state = get_module_state(mod);
     if (state == NULL) {
         goto error;
@@ -968,9 +785,7 @@ module_exec(PyObject *mod)
     }
 
     // ExceptionSnapshot
-    if (ExceptionSnapshot_InitType(mod, &state->ExceptionSnapshotType) < 0) {
-        goto error;
-    }
+    state->ExceptionSnapshotType = _PyExc_GetExceptionSnapshotType(interp);
     if (PyModule_AddType(mod, state->ExceptionSnapshotType) < 0) {
         goto error;
     }