v2.0.0

.github/pull_request_template.md

@@ -6,10 +6,10 @@ Before you submit a pull request, check that it meets these guidelines:
 1. If the pull request adds functionality, the docs should be updated.
 2. Modify the `CHANGELOG.rst`, describing your changes as is specified by the
    guidelines in that document.
-3. The pull request should work for Python 3.9+ on the following platforms:
+3. The pull request should work for Python 3.10+ on the following platforms:
     - Windows 10, version 16299 (Fall Creators Update) and greater
     - Linux distributions with BlueZ >= 5.55
-    - OS X / macOS >= 10.13
+    - OS X / macOS >= 10.15
 4. Squash all your commits on your PR branch, if the commits are not solving
    different problems and you are committing them in the same PR. In that case,
    consider making several PRs instead.

.github/workflows/build_and_test.yml

@@ -16,7 +16,7 @@ jobs:
             fail-fast: false
             matrix:
                 os: [ubuntu-latest, windows-latest, macos-latest]
-                python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+                python-version: ['3.10', '3.11', '3.12', '3.13', '3.14']
         steps:
             -   uses: actions/checkout@v4
             -   name: Set up Python ${{ matrix.python-version }}

.vscode/settings.json

@@ -10,5 +10,8 @@
       "isort.importStrategy": "fromEnvironment",
       "isort.args":["--profile", "black"],
     "flake8.importStrategy": "fromEnvironment",
-    "python.analysis.typeCheckingMode": "strict"
+    "python.analysis.typeCheckingMode": "strict",
+    "python-envs.defaultEnvManager": "ms-python.python:poetry",
+    "python-envs.defaultPackageManager": "ms-python.python:poetry",
+    "python-envs.pythonProjects": []
 }

CHANGELOG.rst

@@ -10,40 +10,67 @@ and this project adheres to `Semantic Versioning <https://semver.org/spec/v2.0.0
 `Unreleased`_
 =============
 
+`2.0.0`_ (2025-11-22)
+=====================
+
+Added
+-----
+* Added ``bleak.backends.get_default_backend()`` and ``BleakBackend`` enum for a centralized backend detection.
+* Added ``BleakClient().backend_id`` and ``BleakScanner().backend_id`` properties to identify the backend in use.
+
+Changed
+-------
+* Use ``"AcquireNotify"`` rather than ``"StartNotify"`` for Linux backend on supported characteristics
+* Allow multiple calls to ``disconnect()`` on Windows to align behavior over all backends.
+* Raise new ``BleakBluetoothNotAvailableError`` when Bluetooth is not supported, turned off or permission is denied.
+
+Fixed
+-----
+* Fixed potential race condition causing timeout while connecting in WinRT backend.
+* Fixed file handle leak in BlueZ backend when D-Bus connection is lost and re-established.
+* Fixed crash in CoreBluetooth backend if an ObjC delegate callback is called after the asyncio run loop stops.
+* Fixed possible deadlock when starting scanning on Windows when Bluetooth is turned off.
+* Fixed "Bluetooth device is turned off" Exception on macOS, when a Bluetooth permission request popup is shown to the user by the OS.
+
+Removed
+-------
+* Removed support for Python 3.9.
+* Removed support for macOS < 10.15.
+
 `1.1.1`_ (2025-09-07)
 =====================
 
 Fixed
 -----
-- Fixed D-Bus connection leak on connection failure in BlueZ backend.
-- Fixed characteristic's max write without response size using wrong characteristic's value. Fixes #1820.
-- Fixed ``AttributeError`` in Python4Android backend when accessing ``is_connected`` before connecting. Fixes #1791.
+* Fixed D-Bus connection leak on connection failure in BlueZ backend.
+* Fixed characteristic's max write without response size using wrong characteristic's value. Fixes #1820.
+* Fixed ``AttributeError`` in Python4Android backend when accessing ``is_connected`` before connecting. Fixes #1791.
 
 `1.1.0`_ (2025-08-10)
 =====================
 
 Added
 -----
-- Added support for Pythonista iOS app backend.
-- Added ``BleakClient.name`` property for getting the peripheral's name. Fixes #1802.
+* Added support for Pythonista iOS app backend.
+* Added ``BleakClient.name`` property for getting the peripheral's name. Fixes #1802.
 
 Fixed
 -----
-- Fixed ``BleakClient.connect()`` on Android when service characteristics have descriptors. Fixes #1803.
-- Fixed disconnect callback not called on Windows when Bleak initiates disconnection.
+* Fixed ``BleakClient.connect()`` on Android when service characteristics have descriptors. Fixes #1803.
+* Fixed disconnect callback not called on Windows when Bleak initiates disconnection.
 
 `1.0.1`_ (2025-06-30)
 =====================
 
 Changed
 -------
-- Added deprecation warnings for importing ``bleak.args.*`` types from ``bleak.backends.*``.
+* Added deprecation warnings for importing ``bleak.args.*`` types from ``bleak.backends.*``.
 
 Fixed
 -----
 
-- Restored ``**kwargs`` in ``BLEDevice()`` constructor. Fixes #1783.
-- Restored importing ``OrPattern`` from ``bleak.backends.bluezdbus.advertisement_monitor``.
+* Restored ``**kwargs`` in ``BLEDevice()`` constructor. Fixes #1783.
+* Restored importing ``OrPattern`` from ``bleak.backends.bluezdbus.advertisement_monitor``.
 
 
 `1.0.0`_ (2025-06-28)
@@ -1120,7 +1147,8 @@ Fixed
 * Bleak created.
 
 
-.. _Unreleased: https://github.com/hbldh/bleak/compare/v1.1.1...develop
+.. _Unreleased: https://github.com/hbldh/bleak/compare/v2.0.0...develop
+.. _2.0.0: https://github.com/hbldh/bleak/compare/v1.1.1...v2.0.0
 .. _1.1.1: https://github.com/hbldh/bleak/compare/v1.1.0...v1.1.1
 .. _1.1.0: https://github.com/hbldh/bleak/compare/v1.0.1...v1.1.0
 .. _1.0.1: https://github.com/hbldh/bleak/compare/v1.0.0...v1.0.1

CONTRIBUTING.rst

@@ -102,10 +102,10 @@ Before you submit a pull request, check that it meets these guidelines:
 1. If the pull request adds functionality, the docs should be updated.
 2. Modify the ``CHANGELOG.rst``, describing your changes as is specified by the
    guidelines in that document.
-3. The pull request should work for Python 3.9+ on the following platforms:
+3. The pull request should work for Python 3.10+ on the following platforms:
     - Windows 10, version 16299 (Fall Creators Update) and greater
     - Linux distributions with BlueZ >= 5.55
-    - OS X / macOS >= 10.13
+    - OS X / macOS >= 10.15
 4. Squash all your commits on your PR branch, if the commits are not solving
    different problems and you are committing them in the same PR. In that case,
    consider making several PRs instead.

README.rst

@@ -47,7 +47,7 @@ Features
 
 * Supports Windows 10, version 16299 (Fall Creators Update) or greater
 * Supports Linux distributions with BlueZ >= 5.55
-* OS X/macOS support via Core Bluetooth API, from at least OS X version 10.13
+* OS X/macOS support via Core Bluetooth API, from at least OS X version 10.15
 * Android backend compatible with python-for-android
 
 Bleak supports reading, writing and getting notifications from

bleak/__init__.py

@@ -33,6 +33,7 @@
 from bleak.args.bluez import BlueZScannerArgs
 from bleak.args.corebluetooth import CBScannerArgs, CBStartNotifyArgs
 from bleak.args.winrt import WinRTClientArgs
+from bleak.backends import BleakBackend
 from bleak.backends.characteristic import BleakGATTCharacteristic
 from bleak.backends.client import BaseBleakClient, get_platform_client_backend_type
 from bleak.backends.descriptor import BleakGATTDescriptor
@@ -60,7 +61,7 @@
 
 
 # prevent tasks from being garbage collected
-_background_tasks = set[asyncio.Task[None]]()
+_background_tasks: set[asyncio.Task[None]] = set()
 
 
 class BleakScanner:
@@ -123,8 +124,10 @@ def __init__(
         backend: Optional[type[BaseBleakScanner]] = None,
         **kwargs: Any,
     ) -> None:
-        PlatformBleakScanner = (
-            get_platform_scanner_backend_type() if backend is None else backend
+        PlatformBleakScanner, backend_id = (
+            get_platform_scanner_backend_type()
+            if backend is None
+            else (backend, backend.__name__)
         )
 
         self._backend = PlatformBleakScanner(
@@ -135,6 +138,19 @@ def __init__(
             cb=cb,
             **kwargs,
         )  # type: ignore
+        self._backend_id = backend_id
+
+    @property
+    def backend_id(self) -> BleakBackend | str:
+        """
+        Gets the identifier of the backend in use.
+
+        The value is one of the :class:`BleakBackend` enum values in case of
+        built-in backends, or a string identifying a custom backend.
+
+        .. versionadded:: 2.0
+        """
+        return self._backend_id
 
     async def __aenter__(self) -> Self:
         await self._backend.start()
@@ -149,7 +165,17 @@ async def __aexit__(
         await self._backend.stop()
 
     async def start(self) -> None:
-        """Start scanning for devices"""
+        """
+        Start scanning for devices.
+
+        Raises:
+            BleakBluetoothNotAvailableError:
+                if Bluetooth is not currently available
+
+        .. versionchanged:: 2.0
+            Now raises :class:`BleakBluetoothNotAvailableError` instead of :class:`BleakError`
+            when Bluetooth is not currently available.
+        """
         await self._backend.start()
 
     async def stop(self) -> None:
@@ -170,7 +196,7 @@ async def advertisement_data(
 
         .. versionadded:: 0.21
         """
-        devices = asyncio.Queue[tuple[BLEDevice, AdvertisementData]]()
+        devices: asyncio.Queue[tuple[BLEDevice, AdvertisementData]] = asyncio.Queue()
 
         unregister_callback = self._backend.register_detection_callback(
             lambda bd, ad: devices.put_nowait((bd, ad))
@@ -490,8 +516,10 @@ def __init__(
         backend: Optional[type[BaseBleakClient]] = None,
         **kwargs: Any,
     ) -> None:
-        PlatformBleakClient = (
-            get_platform_client_backend_type() if backend is None else backend
+        PlatformBleakClient, backend_id = (
+            get_platform_client_backend_type()
+            if backend is None
+            else (backend, backend.__name__)
         )
 
         self._backend = PlatformBleakClient(
@@ -509,6 +537,19 @@ def __init__(
             **kwargs,
         )
         self._pair_before_connect = pair
+        self._backend_id = backend_id
+
+    @property
+    def backend_id(self) -> BleakBackend | str:
+        """
+        Gets the identifier of the backend in use.
+
+        The value is one of the :class:`BleakBackend` enum values in case of
+        built-in backends, or a string identifying a custom backend.
+
+        .. versionadded:: 2.0
+        """
+        return self._backend_id
 
     # device info
 
@@ -523,6 +564,8 @@ def name(self) -> str:
         a Bluetooth address separated with dashes (``-``) instead of colons
         (``:``) (or a UUID on Apple devices). It may also be possible to override
         the device name using the OS's Bluetooth settings.
+
+        .. versionadded:: 1.1
         """
         return self._backend.name
 
@@ -663,7 +706,7 @@ async def read_gatt_char(
             The read data.
 
         Raises:
-            BleakGattCharacteristicNotFoundError: if a characteristic with the
+            BleakCharacteristicNotFoundError: if a characteristic with the
                 handle or UUID specified by ``char_specifier`` could not be found.
             backend-specific exceptions: if the read operation failed.
         """
@@ -712,7 +755,7 @@ async def write_gatt_char(
                 property, which is why an explicit argument is encouraged.
 
         Raises:
-            BleakGattCharacteristicNotFoundError: if a characteristic with the
+            BleakCharacteristicNotFoundError: if a characteristic with the
                 handle or UUID specified by ``char_specifier`` could not be found.
             backend-specific exceptions: if the write operation failed.
 
@@ -771,7 +814,7 @@ def callback(sender: BleakGATTCharacteristic, data: bytearray):
                 CoreBluetooth specific arguments.
 
         Raises:
-            BleakGattCharacteristicNotFoundError: if a characteristic with the
+            BleakCharacteristicNotFoundError: if a characteristic with the
                 handle or UUID specified by ``char_specifier`` could not be found.
             backend-specific exceptions: if the start notification operation failed.
 
@@ -813,7 +856,7 @@ async def stop_notify(
                 BleakGATTCharacteristic object representing it.
 
         Raises:
-            BleakGattCharacteristicNotFoundError: if a characteristic with the
+            BleakCharacteristicNotFoundError: if a characteristic with the
                 handle or UUID specified by ``char_specifier`` could not be found.
             backend-specific exceptions: if the stop notification operation failed.
 

bleak/backends/__init__.py

@@ -1,5 +1,75 @@
-# -*- coding: utf-8 -*-
-# Created on 2017-11-19 by hbldh <[email protected]>
 """
-__init__.py
+Communicating with Bluetooth hardware requires calling OS-specific APIs. These
+are abstracted as "backends" in Bleak.
+
+The backend will be automatically selected based on the operating system Bleak
+is running on. In some cases, this may also depend on a specific runtime, like
+Pythonista on iOS.
 """
+
+import enum
+import os
+import platform
+import sys
+
+from bleak.exc import BleakError
+
+
+class BleakBackend(str, enum.Enum):
+    """
+    Identifiers for available built-in Bleak backends.
+
+    .. versionadded:: 2.0
+    """
+
+    P4ANDROID = "p4android"
+    """
+    Python for Android backend.
+    """
+
+    BLUEZ_DBUS = "bluez_dbus"
+    """
+    BlueZ D-Bus backend for Linux.
+    """
+
+    PYTHONISTA_CB = "pythonista_cb"
+    """
+    Pythonista CoreBluetooth backend for iOS and macOS.
+    """
+
+    CORE_BLUETOOTH = "core_bluetooth"
+    """
+    CoreBluetooth backend for macOS.
+    """
+
+    WIN_RT = "win_rt"
+    """
+    Windows Runtime backend for Windows.
+    """
+
+
+def get_default_backend() -> BleakBackend:
+    """
+    Returns the preferred backend for the current platform/environment.
+
+    .. versionadded:: 2.0
+    """
+    if os.environ.get("P4A_BOOTSTRAP") is not None:
+        return BleakBackend.P4ANDROID
+
+    if platform.system() == "Linux":
+        return BleakBackend.BLUEZ_DBUS
+
+    if sys.platform == "ios" and "Pythonista3.app" in sys.executable:
+        # Must be resolved before checking for "Darwin" (macOS),
+        # as both the Pythonista app for iOS and macOS
+        # return "Darwin" from platform.system()
+        return BleakBackend.PYTHONISTA_CB
+
+    if platform.system() == "Darwin":
+        return BleakBackend.CORE_BLUETOOTH
+
+    if platform.system() == "Windows":
+        return BleakBackend.WIN_RT
+
+    raise BleakError(f"Unsupported platform: {platform.system()}")