WifiManager: guard init_wifi_state (#37413)

* failing test

* fix

* rename

* better

system/ui/lib/tests/test_handle_state_change.py

@@ -347,6 +347,33 @@ class TestThreadRaces:
     assert wm._wifi_state.ssid == "B"
     assert wm._wifi_state.status == ConnectStatus.CONNECTING
 
+  def test_init_wifi_state_race_user_tap_during_dbus(self, mocker):
+    """User taps B while _init_wifi_state's DBus calls are in flight.
+
+    _init_wifi_state runs from set_active(True) or worker error paths. It does
+    2 DBus calls (device State property + _get_active_wifi_connection) then
+    unconditionally writes _wifi_state. If the user taps a network during those
+    calls, _set_connecting("B") is overwritten with stale NM ground truth.
+    """
+    wm = _make_wm(mocker, connections={"A": "/path/A", "B": "/path/B"})
+    wm._wifi_device = "/dev/wifi0"
+    wm._router_main = mocker.MagicMock()
+
+    state_reply = mocker.MagicMock()
+    state_reply.body = [('u', NMDeviceState.ACTIVATED)]
+    wm._router_main.send_and_get_reply.return_value = state_reply
+
+    def user_taps_b_during_dbus(*args, **kwargs):
+      wm._set_connecting("B")
+      return ("/path/A", {})
+
+    wm._get_active_wifi_connection.side_effect = user_taps_b_during_dbus
+
+    wm._init_wifi_state()
+
+    assert wm._wifi_state.ssid == "B"
+    assert wm._wifi_state.status == ConnectStatus.CONNECTING
+
 
 # ---------------------------------------------------------------------------
 # Full sequences (NM signal order from real devices)

system/ui/lib/wifi_manager.py

@@ -197,7 +197,7 @@ class WifiManager:
     self._networks_updated: list[Callable[[list[Network]], None]] = []
     self._disconnected: list[Callable[[], None]] = []
 
-    self._lock = threading.Lock()
+    self._scan_lock = threading.Lock()
     self._scan_thread = threading.Thread(target=self._network_scanner, daemon=True)
     self._state_thread = threading.Thread(target=self._monitor_state, daemon=True)
     self._initialize()
@@ -227,6 +227,8 @@ class WifiManager:
         cloudlog.warning("No WiFi device found")
         return
 
+      epoch = self._user_epoch
+
       dev_addr = DBusAddress(self._wifi_device, bus_name=NM, interface=NM_DEVICE_IFACE)
       dev_state = self._router_main.send_and_get_reply(Properties(dev_addr).get('State')).body[0][1]
 
@@ -239,6 +241,10 @@ class WifiManager:
       conn_path, _ = self._get_active_wifi_connection()
       if conn_path:
         wifi_state.ssid = next((s for s, p in self._connections.items() if p == conn_path), None)
+
+      if self._user_epoch != epoch:
+        return
+
       self._wifi_state = wifi_state
 
     if block:
@@ -281,11 +287,13 @@ class WifiManager:
 
   @property
   def connecting_to_ssid(self) -> str | None:
-    return self._wifi_state.ssid if self._wifi_state.status == ConnectStatus.CONNECTING else None
+    wifi_state = self._wifi_state
+    return wifi_state.ssid if wifi_state.status == ConnectStatus.CONNECTING else None
 
   @property
   def connected_ssid(self) -> str | None:
-    return self._wifi_state.ssid if self._wifi_state.status == ConnectStatus.CONNECTED else None
+    wifi_state = self._wifi_state
+    return wifi_state.ssid if wifi_state.status == ConnectStatus.CONNECTED else None
 
   @property
   def tethering_password(self) -> str:
@@ -822,7 +830,7 @@ class WifiManager:
       return
 
     def worker():
-      with self._lock:
+      with self._scan_lock:
         if self._wifi_device is None:
           cloudlog.warning("No WiFi device found")
           return