Fix: org.gnome.SessionManager RuntimeError (Issue 276)

pyproject.toml

@@ -104,6 +104,7 @@ exclude_lines = [
     "if (?:typing\\.)?TYPE_CHECKING:",
     "@(abc\\.)?abstractmethod",
     "@(typing\\.)?overload",
+    "raise NotImplementedError"
 ]
 
 [tool.coverage.coverage_conditional_plugin.omit]

src/wakepy/core/dbus.py

@@ -264,7 +264,7 @@ def __repr__(self) -> str:
         return f"<{self.method.service} {self.args} | bus: {self.method.bus}>"
 
 
-class DBusAdapter:
+class DBusAdapter:  # pragma: no-cover-if-no-dbus
     """Defines the DBusAdapter interface. This is to be subclassed, and each
     subclass is usually an implementation for a DBusAdapter using single
     python (dbus-)library.
@@ -279,6 +279,10 @@ class DBusAdapter:
     wakepy (Modes).
     """
 
+    def __init__(self) -> None:
+        # The values are DBusConnections. Type is defined by the used library.
+        self._connections: Dict[Optional[Union[str, BusType]], object] = dict()
+
     def process(self, call: DBusMethodCall) -> object:
         """Processes a :class:`~wakepy.core.DBusMethodCall`.
 
@@ -290,6 +294,29 @@ def process(self, call: DBusMethodCall) -> object:
           created within the :func:`~wakepy.DBusAdapter.process` call (this may
           of course be cached)."""
 
+    def _get_connection(
+        self, bus: Optional[Union[str, BusType]] = BusType.SESSION
+    ) -> object:
+        """Gets either a new connection or a cached one, if there is such.
+        Caching of connections is done on bus level."""
+
+        if bus in self._connections:
+            return self._connections[bus]
+
+        connection = self._create_new_connection(bus)
+
+        self._connections[bus] = connection
+        return connection
+
+    def _create_new_connection(
+        self, bus: Optional[Union[str, BusType]] = BusType.SESSION
+    ) -> object:
+        """Create a new Dbus connection for a bus using the library of choice.
+        For example, when creating DBusAdapter subclass for jeepney, could
+        return an instance of ``jeepney.io.blocking.DBusConnection``.
+        """
+        raise NotImplementedError("Implement in subclass")
+
 
 def get_dbus_adapter(
     dbus_adapter: Optional[Type[DBusAdapter] | DBusAdapterTypeSeq] = None,

src/wakepy/dbus_adapters/jeepney.py

@@ -1,8 +1,19 @@
+from __future__ import annotations
+
+import typing
+from typing import cast
+
 from jeepney import DBusAddress, new_method_call
-from jeepney.io.blocking import open_dbus_connection
+from jeepney.io.blocking import DBusConnection, open_dbus_connection
 from jeepney.wrappers import unwrap_msg
 
 from wakepy.core import DBusAdapter, DBusMethodCall
+from wakepy.core.dbus import BusType
+
+if typing.TYPE_CHECKING:
+    from typing import Optional, Union
+
+    TypeOfBus = Optional[Union[BusType, str]]
 
 
 class DBusNotFoundError(RuntimeError): ...
@@ -30,8 +41,17 @@ def process(self, call: DBusMethodCall) -> object:
             signature=call.method.signature,
             body=call.args,
         )
+
+        connection = cast(DBusConnection, self._get_connection(call.method.bus))  # type: ignore[no-any-unimported]
+        reply = connection.send_and_get_reply(msg, timeout=self.timeout)
+        resp = unwrap_msg(reply)
+        return resp
+
+    def _create_new_connection(  # type: ignore[no-any-unimported]
+        self, bus: TypeOfBus = BusType.SESSION
+    ) -> DBusConnection:
         try:
-            connection = open_dbus_connection(bus=call.method.bus)
+            return open_dbus_connection(bus=bus)
         except KeyError as exc:
             if "DBUS_SESSION_BUS_ADDRESS" in str(exc):
                 raise DBusNotFoundError(
@@ -44,6 +64,3 @@ def process(self, call: DBusMethodCall) -> object:
                 ) from exc
             else:
                 raise
-        reply = connection.send_and_get_reply(msg, timeout=self.timeout)
-        resp = unwrap_msg(reply)
-        return resp

tasks.py

@@ -86,7 +86,8 @@ def test(c, pdb: bool = False) -> None:
     run = get_run_with_print(c)
     pdb_flag = " --pdb " if pdb else ""
     res = run(
-        f"python -m pytest {pdb_flag}--cov-branch --cov wakepy --cov-fail-under=100",
+        f"env -u DBUS_SESSION_BUS_ADDRESS python -m pytest {pdb_flag}--cov-branch "
+        "--cov wakepy --cov-fail-under=100",
         ignore_errors=True,
     )
     if res.exited:

tests/integration/conftest.py

@@ -6,6 +6,7 @@
 import logging
 import subprocess
 import sys
+import warnings
 
 import pytest
 
@@ -32,7 +33,11 @@ def gc_collect_after_dbus_integration_tests():
     # this as garbage colletion is triggered also automatically. The garbage
     # collection must be triggered here manually as the warnings are
     # ResourceWarning is only filtered away in the dbus integration tests.
-    gc.collect()
+
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore")
+        gc.collect()
+
     logger.debug("called gc.collect")
 
 

tests/integration/test_dbus_adapters.py

@@ -180,3 +180,11 @@ def test_random_keyerror_on_connection_creation(
                 match="Some other reason",
             ):
                 self.adapter.process(self.call)
+
+
+def test_jeepney_adapter_caching(private_bus: str):
+    adapter = JeepneyDBusAdapter()
+    con = adapter._get_connection(private_bus)
+
+    # Call again with same bus name -> get same (cached) connection.
+    assert adapter._get_connection(private_bus) is con

tox.ini

@@ -13,8 +13,6 @@ minversion = 4.8.0
 [testenv]
 description = run the tests with pytest
 deps = -r{toxinidir}/requirements/requirements-test.txt
-passenv =
-    DBUS_SESSION_BUS_ADDRESS
 commands =
     ; -W error: turn warnings into errors
     {envpython} -m pytest -W error {tty:--color=yes} \