Instantiate BaseBleakClient.services collection after service discovery

CHANGELOG.rst

@@ -20,6 +20,8 @@ Changed
 * Dropped ``async-timeout`` dependency on Python >= 3.11.
 * Deprecated ``BLEDevice.rssi`` and ``BLEDevice.metadata``. Fixes #1025.
 * ``BLEDevice`` now uses ``__slots__`` to reduce memory usage.
+* ``BaseBleakClient.services`` is now ``None`` instead of empty service collection
+  until services are discovered.
 
 Fixed
 -----

bleak/__init__.py

@@ -576,7 +576,13 @@ def services(self) -> BleakGATTServiceCollection:
         Gets the collection of GATT services available on the device.
 
         The returned value is only valid as long as the device is connected.
+
+        Raises:
+            BleakError: if service discovery has not been performed yet during this connection.
         """
+        if not self._backend.services:
+            raise BleakError("Service Discovery has not been performed yet")
+
         return self._backend.services
 
     # I/O methods

bleak/backends/bluezdbus/client.py

@@ -309,8 +309,7 @@ def _cleanup_all(self) -> None:
             self._bus = None
 
             # Reset all stored services.
-            self.services = BleakGATTServiceCollection()
-            self._services_resolved = False
+            self.services = None
 
     async def disconnect(self) -> bool:
         """Disconnect from the specified GATT server.
@@ -587,15 +586,14 @@ async def get_services(
         if not self.is_connected:
             raise BleakError("Not connected")
 
-        if self._services_resolved:
+        if self.services is not None:
             return self.services
 
         manager = await get_global_bluez_manager()
 
         self.services = await manager.get_services(
             self._device_path, dangerous_use_bleak_cache
         )
-        self._services_resolved = True
 
         return self.services
 

bleak/backends/client.py

@@ -42,9 +42,7 @@ def __init__(self, address_or_ble_device: Union[BLEDevice, str], **kwargs):
         else:
             self.address = address_or_ble_device
 
-        self.services = BleakGATTServiceCollection()
-
-        self._services_resolved = False
+        self.services: Optional[BleakGATTServiceCollection] = None
 
         self._timeout = kwargs.get("timeout", 10.0)
         self._disconnected_callback = kwargs.get("disconnected_callback")

bleak/backends/corebluetooth/client.py

@@ -14,7 +14,7 @@
     CBPeripheral,
     CBPeripheralStateConnected,
 )
-from Foundation import NSArray, NSData
+from Foundation import NSData
 
 from ... import BleakScanner
 from ...exc import BleakError, BleakDeviceNotFoundError
@@ -57,8 +57,6 @@ def __init__(self, address_or_ble_device: Union[BLEDevice, str], **kwargs):
                 self._central_manager_delegate,
             ) = address_or_ble_device.details
 
-        self._services: Optional[NSArray] = None
-
     def __str__(self):
         return "BleakClientCoreBluetooth ({})".format(self.address)
 
@@ -91,11 +89,9 @@ async def connect(self, **kwargs) -> bool:
             )
 
         def disconnect_callback():
-            self.services = BleakGATTServiceCollection()
             # Ensure that `get_services` retrieves services again, rather
             # than using the cached object
-            self._services_resolved = False
-            self._services = None
+            self.services = None
 
             # If there are any pending futures waiting for delegate callbacks, we
             # need to raise an exception since the callback will no longer be
@@ -190,20 +186,22 @@ async def get_services(self, **kwargs) -> BleakGATTServiceCollection:
            A :py:class:`bleak.backends.service.BleakGATTServiceCollection` with this device's services tree.
 
         """
-        if self._services is not None:
+        if self.services is not None:
             return self.services
 
+        services = BleakGATTServiceCollection()
+
         logger.debug("Retrieving services...")
-        services = await self._delegate.discover_services()
+        cb_services = await self._delegate.discover_services()
 
-        for service in services:
+        for service in cb_services:
             serviceUUID = service.UUID().UUIDString()
             logger.debug(
                 "Retrieving characteristics for service {}".format(serviceUUID)
             )
             characteristics = await self._delegate.discover_characteristics(service)
 
-            self.services.add_service(BleakGATTServiceCoreBluetooth(service))
+            services.add_service(BleakGATTServiceCoreBluetooth(service))
 
             for characteristic in characteristics:
                 cUUID = characteristic.UUID().UUIDString()
@@ -212,7 +210,7 @@ async def get_services(self, **kwargs) -> BleakGATTServiceCollection:
                 )
                 descriptors = await self._delegate.discover_descriptors(characteristic)
 
-                self.services.add_characteristic(
+                services.add_characteristic(
                     BleakGATTCharacteristicCoreBluetooth(
                         characteristic,
                         self._peripheral.maximumWriteValueLengthForType_(
@@ -221,16 +219,15 @@ async def get_services(self, **kwargs) -> BleakGATTServiceCollection:
                     )
                 )
                 for descriptor in descriptors:
-                    self.services.add_descriptor(
+                    services.add_descriptor(
                         BleakGATTDescriptorCoreBluetooth(
                             descriptor,
                             cb_uuid_to_str(characteristic.UUID()),
                             int(characteristic.handle()),
                         )
                     )
         logger.debug("Services resolved for %s", str(self))
-        self._services_resolved = True
-        self._services = services
+        self.services = services
         return self.services
 
     async def read_gatt_char(

bleak/backends/p4android/client.py

@@ -151,8 +151,7 @@ async def disconnect(self) -> bool:
         self.__callbacks = None
 
         # Reset all stored services.
-        self.services = BleakGATTServiceCollection()
-        self._services_resolved = False
+        self.services = None
 
         return True
 
@@ -246,14 +245,16 @@ async def get_services(self) -> BleakGATTServiceCollection:
            A :py:class:`bleak.backends.service.BleakGATTServiceCollection` with this device's services tree.
 
         """
-        if self._services_resolved:
+        if self.services is not None:
             return self.services
 
+        services = BleakGATTServiceCollection()
+
         logger.debug("Get Services...")
         for java_service in self.__gatt.getServices():
 
             service = BleakGATTServiceP4Android(java_service)
-            self.services.add_service(service)
+            services.add_service(service)
 
             for java_characteristic in java_service.getCharacteristics():
 
@@ -263,7 +264,7 @@ async def get_services(self) -> BleakGATTServiceCollection:
                     service.handle,
                     self.__mtu - 3,
                 )
-                self.services.add_characteristic(characteristic)
+                services.add_characteristic(characteristic)
 
                 for descriptor_index, java_descriptor in enumerate(
                     java_characteristic.getDescriptors()
@@ -275,9 +276,9 @@ async def get_services(self) -> BleakGATTServiceCollection:
                         characteristic.handle,
                         descriptor_index,
                     )
-                    self.services.add_descriptor(descriptor)
+                    services.add_descriptor(descriptor)
 
-        self._services_resolved = True
+        self.services = services
         return self.services
 
     # IO methods

bleak/backends/winrt/client.py

@@ -414,7 +414,6 @@ def max_pdu_size_changed_handler(sender: GattSession, args):
                             # services did not change while getting services,
                             # so this is the final result
                             self.services = get_services_task.result()
-                            self._services_resolved = True
                             break
 
                         logger.debug(
@@ -463,10 +462,10 @@ async def disconnect(self) -> bool:
         self._notification_callbacks.clear()
 
         # Dispose all service components that we have requested and created.
-        for service in self.services:
-            service.obj.close()
-        self.services = BleakGATTServiceCollection()
-        self._services_resolved = False
+        if self.services:
+            for service in self.services:
+                service.obj.close()
+            self.services = None
 
         # Without this, disposing the BluetoothLEDevice won't disconnect it
         if self._session:
@@ -616,7 +615,7 @@ async def get_services(
         """
 
         # Return the Service Collection.
-        if self._services_resolved:
+        if self.services is not None:
             return self.services
 
         logger.debug(