Fix property exceptions always causing AccessDenied error

src/sdbus/sd_bus_internals.h

@@ -46,6 +46,15 @@
                 new_object;                         \
         })
 
+#define CALL_PYTHON_GOTO_FAIL(py_function)          \
+        ({                                          \
+                PyObject* new_object = py_function; \
+                if (new_object == NULL) {           \
+                        goto fail;                  \
+                }                                   \
+                new_object;                         \
+        })
+
 #define PYTHON_ERR_OCCURED      \
         if (PyErr_Occurred()) { \
                 return NULL;    \

src/sdbus/sd_bus_internals_interface.c

@@ -18,6 +18,7 @@
     License along with this library; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */
+#include <systemd/sd-bus.h>
 #include "sd_bus_internals.h"
 
 // TODO: adding interface to different buses, recalculating vtable
@@ -413,16 +414,23 @@ static int _SdBusInterface_property_get_callback(sd_bus* Py_UNUSED(bus),
                                                  const char* property,
                                                  sd_bus_message* reply,
                                                  void* userdata,
-                                                 sd_bus_error* Py_UNUSED(ret_error)) {
+                                                 sd_bus_error* ret_error) {
         SdBusInterfaceObject* self = userdata;
-        PyObject* property_name_bytes CLEANUP_PY_OBJECT = PyBytes_FromString(property);
-        PyObject* get_call = CALL_PYTHON_CHECK_RETURN_NEG1(PyDict_GetItem(self->property_get_dict, property_name_bytes));
+        PyObject* property_name_bytes CLEANUP_PY_OBJECT = NULL;
+        PyObject* get_call = NULL;
+        PyObject* new_message CLEANUP_PY_OBJECT = NULL;
 
-        PyObject* new_message CLEANUP_PY_OBJECT = CALL_PYTHON_CHECK_RETURN_NEG1(SD_BUS_PY_CLASS_DUNDER_NEW(SdBusMessage_class));
+        property_name_bytes = CALL_PYTHON_GOTO_FAIL(PyBytes_FromString(property));
+        get_call = CALL_PYTHON_GOTO_FAIL(PyDict_GetItem(self->property_get_dict, property_name_bytes));
+
+        new_message = CALL_PYTHON_GOTO_FAIL(SD_BUS_PY_CLASS_DUNDER_NEW(SdBusMessage_class));
         _SdBusMessage_set_messsage((SdBusMessageObject*)new_message, reply);
 
-        Py_XDECREF(CALL_PYTHON_CHECK_RETURN_NEG1(PyObject_CallFunctionObjArgs(get_call, new_message, NULL)));
+        Py_XDECREF(CALL_PYTHON_GOTO_FAIL(PyObject_CallFunctionObjArgs(get_call, new_message, NULL)));
         return 0;
+fail:
+        sd_bus_error_set(ret_error, SD_BUS_ERROR_FAILED, "");
+        return -1;
 }
 
 static int _SdBusInterface_property_set_callback(sd_bus* Py_UNUSED(bus),

test/test_low_level_errors.py

@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+# Copyright (C) 2020-2022 igo95862
+
+# This file is part of python-sdbus
+
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+from __future__ import annotations
+
+from asyncio import get_running_loop, wait_for
+from typing import Any
+
+from sdbus.unittest import IsolatedDbusTestCase
+
+from sdbus import (
+    DbusFailedError,
+    DbusInterfaceCommonAsync,
+    dbus_method_async,
+    dbus_property_async,
+    request_default_bus_name_async,
+)
+
+HELLO_WORLD = 'Hello, world!'
+
+
+class InterfaceWithErrors(
+    DbusInterfaceCommonAsync,
+    interface_name='org.example.test',
+):
+    @dbus_property_async('s')
+    def test_str(self) -> str:
+        raise RuntimeError
+
+    @dbus_method_async(result_signature='s')
+    async def hello_error(self) -> str:
+        raise AttributeError
+
+    @dbus_method_async(result_signature='s')
+    async def hello_world(self) -> str:
+        return HELLO_WORLD
+
+
+class TestLowLevelErrors(IsolatedDbusTestCase):
+    async def test_low_level_error(self) -> None:
+        await request_default_bus_name_async('org.test')
+        test_object = InterfaceWithErrors()
+        test_object.export_to_dbus('/')
+
+        test_object_connection = InterfaceWithErrors.new_proxy(
+            'org.test', '/')
+
+        loop = get_running_loop()
+
+        def silence_exceptions(*args: Any, **kwrags: Any) -> None:
+            ...
+
+        loop.set_exception_handler(silence_exceptions)
+
+        with self.assertRaises(DbusFailedError) as cm:
+            await wait_for(test_object_connection.test_str.get_async(),
+                           timeout=1)
+
+        should_be_dbus_failed = cm.exception
+        self.assertIs(should_be_dbus_failed.__class__, DbusFailedError)
+
+        await test_object_connection.hello_world()