gh-102192: Replace PyErr_Fetch/Restore etc by more efficient alternatives (in Modules/)

Modules/_asynciomodule.c

@@ -1422,7 +1422,6 @@ _asyncio_Future__make_cancelled_error_impl(FutureObj *self)
 static void
 FutureObj_finalize(FutureObj *fut)
 {
-    PyObject *error_type, *error_value, *error_traceback;
     PyObject *context;
     PyObject *message = NULL;
     PyObject *func;
@@ -1434,7 +1433,7 @@ FutureObj_finalize(FutureObj *fut)
     fut->fut_log_tb = 0;
 
     /* Save the current exception, if any. */
-    PyErr_Fetch(&error_type, &error_value, &error_traceback);
+    PyObject *exc = PyErr_GetRaisedException();
 
     context = PyDict_New();
     if (context == NULL) {
@@ -1476,7 +1475,7 @@ FutureObj_finalize(FutureObj *fut)
     Py_XDECREF(message);
 
     /* Restore the saved exception. */
-    PyErr_Restore(error_type, error_value, error_traceback);
+    PyErr_SetRaisedException(exc);
 }
 
 static PyMethodDef FutureType_methods[] = {
@@ -2491,14 +2490,13 @@ TaskObj_finalize(TaskObj *task)
     PyObject *context;
     PyObject *message = NULL;
     PyObject *func;
-    PyObject *error_type, *error_value, *error_traceback;
 
     if (task->task_state != STATE_PENDING || !task->task_log_destroy_pending) {
         goto done;
     }
 
     /* Save the current exception, if any. */
-    PyErr_Fetch(&error_type, &error_value, &error_traceback);
+    PyObject *exc = PyErr_GetRaisedException();
 
     context = PyDict_New();
     if (context == NULL) {
@@ -2541,7 +2539,7 @@ TaskObj_finalize(TaskObj *task)
     Py_XDECREF(message);
 
     /* Restore the saved exception. */
-    PyErr_Restore(error_type, error_value, error_traceback);
+    PyErr_SetRaisedException(exc);
 
 done:
     FutureObj_finalize((FutureObj*)task);
@@ -2766,8 +2764,6 @@ task_step_impl(asyncio_state *state, TaskObj *task, PyObject *exc)
     }
 
     if (gen_status == PYGEN_RETURN || gen_status == PYGEN_ERROR) {
-        PyObject *et, *ev, *tb;
-
         if (result != NULL) {
             /* The error is StopIteration and that means that
                the underlying coroutine has resolved */
@@ -2794,52 +2790,39 @@ task_step_impl(asyncio_state *state, TaskObj *task, PyObject *exc)
 
         if (PyErr_ExceptionMatches(state->asyncio_CancelledError)) {
             /* CancelledError */
-            PyErr_Fetch(&et, &ev, &tb);
-            assert(et);
-            PyErr_NormalizeException(&et, &ev, &tb);
-            if (tb != NULL) {
-                PyException_SetTraceback(ev, tb);
-                Py_DECREF(tb);
-            }
-            Py_XDECREF(et);
+
+            PyObject *exc = PyErr_GetRaisedException();
+            assert(exc);
 
             FutureObj *fut = (FutureObj*)task;
             /* transfer ownership */
-            fut->fut_cancelled_exc = ev;
+            fut->fut_cancelled_exc = exc;
 
             return future_cancel(state, fut, NULL);
         }
 
         /* Some other exception; pop it and call Task.set_exception() */
-        PyErr_Fetch(&et, &ev, &tb);
-        assert(et);
-        PyErr_NormalizeException(&et, &ev, &tb);
-        if (tb != NULL) {
-            PyException_SetTraceback(ev, tb);
-        }
+        PyObject *exc = PyErr_GetRaisedException();
+        assert(exc);
 
-        o = future_set_exception(state, (FutureObj*)task, ev);
+        o = future_set_exception(state, (FutureObj*)task, exc);
         if (!o) {
             /* An exception in Task.set_exception() */
-            Py_DECREF(et);
-            Py_XDECREF(tb);
-            Py_XDECREF(ev);
+            Py_DECREF(exc);
             goto fail;
         }
         assert(o == Py_None);
         Py_DECREF(o);
 
-        if (PyErr_GivenExceptionMatches(et, PyExc_KeyboardInterrupt) ||
-            PyErr_GivenExceptionMatches(et, PyExc_SystemExit))
+        if (PyErr_GivenExceptionMatches(exc, PyExc_KeyboardInterrupt) ||
+            PyErr_GivenExceptionMatches(exc, PyExc_SystemExit))
         {
             /* We've got a KeyboardInterrupt or a SystemError; re-raise it */
-            PyErr_Restore(et, ev, tb);
+            PyErr_SetRaisedException(exc);
             goto fail;
         }
 
-        Py_DECREF(et);
-        Py_XDECREF(tb);
-        Py_XDECREF(ev);
+        Py_DECREF(exc);
 
         Py_RETURN_NONE;
     }
@@ -3059,10 +3042,9 @@ task_step(asyncio_state *state, TaskObj *task, PyObject *exc)
     res = task_step_impl(state, task, exc);
 
     if (res == NULL) {
-        PyObject *et, *ev, *tb;
-        PyErr_Fetch(&et, &ev, &tb);
+        PyObject *exc = PyErr_GetRaisedException();
         leave_task(state, task->task_loop, (PyObject*)task);
-        _PyErr_ChainExceptions(et, ev, tb); /* Normalizes (et, ev, tb) */
+        _PyErr_ChainExceptions1(exc);
         return NULL;
     }
     else {
@@ -3079,7 +3061,6 @@ task_step(asyncio_state *state, TaskObj *task, PyObject *exc)
 static PyObject *
 task_wakeup(TaskObj *task, PyObject *o)
 {
-    PyObject *et, *ev, *tb;
     PyObject *result;
     assert(o);
 
@@ -3111,18 +3092,12 @@ task_wakeup(TaskObj *task, PyObject *o)
         /* exception raised */
     }
 
-    PyErr_Fetch(&et, &ev, &tb);
-    assert(et);
-    PyErr_NormalizeException(&et, &ev, &tb);
-    if (tb != NULL) {
-        PyException_SetTraceback(ev, tb);
-    }
+    PyObject *exc = PyErr_GetRaisedException();
+    assert(exc);
 
-    result = task_step(state, task, ev);
+    result = task_step(state, task, exc);
 
-    Py_DECREF(et);
-    Py_XDECREF(tb);
-    Py_XDECREF(ev);
+    Py_DECREF(exc);
 
     return result;
 }

Modules/_io/_iomodule.c

@@ -437,10 +437,9 @@ _io_open_impl(PyObject *module, PyObject *file, const char *mode,
 
   error:
     if (result != NULL) {
-        PyObject *exc, *val, *tb, *close_result;
-        PyErr_Fetch(&exc, &val, &tb);
-        close_result = PyObject_CallMethodNoArgs(result, &_Py_ID(close));
-        _PyErr_ChainExceptions(exc, val, tb);
+        PyObject *exc = PyErr_GetRaisedException();
+        PyObject *close_result = PyObject_CallMethodNoArgs(result, &_Py_ID(close));
+        _PyErr_ChainExceptions1(exc);
         Py_XDECREF(close_result);
         Py_DECREF(result);
     }

Modules/_io/bufferedio.c

@@ -472,12 +472,13 @@ buffered_closed_get(buffered *self, void *context)
 static PyObject *
 buffered_close(buffered *self, PyObject *args)
 {
-    PyObject *res = NULL, *exc = NULL, *val, *tb;
+    PyObject *res = NULL;
     int r;
 
     CHECK_INITIALIZED(self)
-    if (!ENTER_BUFFERED(self))
+    if (!ENTER_BUFFERED(self)) {
         return NULL;
+    }
 
     r = buffered_closed(self);
     if (r < 0)
@@ -497,12 +498,16 @@ buffered_close(buffered *self, PyObject *args)
     /* flush() will most probably re-take the lock, so drop it first */
     LEAVE_BUFFERED(self)
     res = PyObject_CallMethodNoArgs((PyObject *)self, &_Py_ID(flush));
-    if (!ENTER_BUFFERED(self))
+    if (!ENTER_BUFFERED(self)) {
         return NULL;
-    if (res == NULL)
-        PyErr_Fetch(&exc, &val, &tb);
-    else
+    }
+    PyObject *exc = NULL;
+    if (res == NULL) {
+        exc = PyErr_GetRaisedException();
+    }
+    else {
         Py_DECREF(res);
+    }
 
     res = PyObject_CallMethodNoArgs(self->raw, &_Py_ID(close));
 
@@ -512,7 +517,7 @@ buffered_close(buffered *self, PyObject *args)
     }
 
     if (exc != NULL) {
-        _PyErr_ChainExceptions(exc, val, tb);
+        _PyErr_ChainExceptions1(exc);
         Py_CLEAR(res);
     }
 
@@ -637,17 +642,14 @@ _set_BlockingIOError(const char *msg, Py_ssize_t written)
 static Py_ssize_t *
 _buffered_check_blocking_error(void)
 {
-    PyObject *t, *v, *tb;
-    PyOSErrorObject *err;
-
-    PyErr_Fetch(&t, &v, &tb);
-    if (v == NULL || !PyErr_GivenExceptionMatches(v, PyExc_BlockingIOError)) {
-        PyErr_Restore(t, v, tb);
+    PyObject *exc = PyErr_GetRaisedException();
+    if (exc == NULL || !PyErr_GivenExceptionMatches(exc, PyExc_BlockingIOError)) {
+        PyErr_SetRaisedException(exc);
         return NULL;
     }
-    err = (PyOSErrorObject *) v;
+    PyOSErrorObject *err = (PyOSErrorObject *)exc;
     /* TODO: sanity check (err->written >= 0) */
-    PyErr_Restore(t, v, tb);
+    PyErr_SetRaisedException(exc);
     return &err->written;
 }
 
@@ -749,13 +751,11 @@ _buffered_init(buffered *self)
 int
 _PyIO_trap_eintr(void)
 {
-    PyObject *typ, *val, *tb;
-    PyOSErrorObject *env_err;
-    if (!PyErr_ExceptionMatches(PyExc_OSError))
+    if (!PyErr_ExceptionMatches(PyExc_OSError)) {
         return 0;
-    PyErr_Fetch(&typ, &val, &tb);
-    PyErr_NormalizeException(&typ, &val, &tb);
-    env_err = (PyOSErrorObject *) val;
+    }
+    PyObject *exc = PyErr_GetRaisedException();
+    PyOSErrorObject *env_err = (PyOSErrorObject *)exc;
     assert(env_err != NULL);
     if (env_err->myerrno != NULL) {
         assert(EINTR > 0 && EINTR < INT_MAX);
@@ -764,14 +764,12 @@ _PyIO_trap_eintr(void)
         int myerrno = PyLong_AsLongAndOverflow(env_err->myerrno, &overflow);
         PyErr_Clear();
         if (myerrno == EINTR) {
-            Py_DECREF(typ);
-            Py_DECREF(val);
-            Py_XDECREF(tb);
+            Py_DECREF(exc);
             return 1;
         }
     }
     /* This silences any error set by PyObject_RichCompareBool() */
-    PyErr_Restore(typ, val, tb);
+    PyErr_SetRaisedException(exc);
     return 0;
 }
 
@@ -2228,15 +2226,17 @@ bufferedrwpair_writable(rwpair *self, PyObject *Py_UNUSED(ignored))
 static PyObject *
 bufferedrwpair_close(rwpair *self, PyObject *Py_UNUSED(ignored))
 {
-    PyObject *exc = NULL, *val, *tb;
+    PyObject *exc = NULL;
     PyObject *ret = _forward_call(self->writer, &_Py_ID(close), NULL);
-    if (ret == NULL)
-        PyErr_Fetch(&exc, &val, &tb);
-    else
+    if (ret == NULL) {
+        exc = PyErr_GetRaisedException();
+    }
+    else {
         Py_DECREF(ret);
+    } 
     ret = _forward_call(self->reader, &_Py_ID(close), NULL);
     if (exc != NULL) {
-        _PyErr_ChainExceptions(exc, val, tb);
+        _PyErr_ChainExceptions1(exc);
         Py_CLEAR(ret);
     }
     return ret;

Modules/_io/fileio.c

@@ -88,14 +88,13 @@ static PyObject *
 fileio_dealloc_warn(fileio *self, PyObject *source)
 {
     if (self->fd >= 0 && self->closefd) {
-        PyObject *exc, *val, *tb;
-        PyErr_Fetch(&exc, &val, &tb);
+        PyObject *exc = PyErr_GetRaisedException();
         if (PyErr_ResourceWarning(source, 1, "unclosed file %R", source)) {
             /* Spurious errors can appear at shutdown */
             if (PyErr_ExceptionMatches(PyExc_Warning))
                 PyErr_WriteUnraisable((PyObject *) self);
         }
-        PyErr_Restore(exc, val, tb);
+        PyErr_SetRaisedException(exc);
     }
     Py_RETURN_NONE;
 }
@@ -140,28 +139,33 @@ _io_FileIO_close_impl(fileio *self)
 /*[clinic end generated code: output=7737a319ef3bad0b input=f35231760d54a522]*/
 {
     PyObject *res;
-    PyObject *exc, *val, *tb;
+    PyObject *exc;
     int rc;
     res = PyObject_CallMethodOneArg((PyObject*)&PyRawIOBase_Type,
                                      &_Py_ID(close), (PyObject *)self);
     if (!self->closefd) {
         self->fd = -1;
         return res;
     }
-    if (res == NULL)
-        PyErr_Fetch(&exc, &val, &tb);
+    if (res == NULL) {
+        exc = PyErr_GetRaisedException();
+    }
     if (self->finalizing) {
         PyObject *r = fileio_dealloc_warn(self, (PyObject *) self);
-        if (r)
+        if (r) {
             Py_DECREF(r);
-        else
+        }
+        else {
             PyErr_Clear();
+        }
     }
     rc = internal_close(self);
-    if (res == NULL)
-        _PyErr_ChainExceptions(exc, val, tb);
-    if (rc < 0)
+    if (res == NULL) {
+        _PyErr_ChainExceptions1(exc);
+    }
+    if (rc < 0) {
         Py_CLEAR(res);
+    }
     return res;
 }
 
@@ -487,10 +491,9 @@ _io_FileIO___init___impl(fileio *self, PyObject *nameobj, const char *mode,
     if (!fd_is_own)
         self->fd = -1;
     if (self->fd >= 0) {
-        PyObject *exc, *val, *tb;
-        PyErr_Fetch(&exc, &val, &tb);
+        PyObject *exc = PyErr_GetRaisedException();
         internal_close(self);
-        _PyErr_ChainExceptions(exc, val, tb);
+        _PyErr_ChainExceptions1(exc);
     }
 
  done: