Appium新版本引发的一个问题

准备工作

测试代码

from appium import webdriver
des_cap = {'platformName': 'android'}
driver = webdriver.Remote(command_executor='http://127.0.0.1:4723/wd/hub',
                          desired_capabilities=des_cap)

测试环境

python 3.10，虚拟环境
pycharm 2018 community
测试时间 2023-7-20

场景一: 默认安装 PASS

在pycharm中安装appium-python-client，版本不指定，此时是2.11.1
对应依赖selenium4.10.0
执行示例代码
测试通过
??? 所以博主你要表达啥
继续看下去

场景二:appium-python-client2.6.0+selenium4.10 FAIL

你根据指定版本安装appium-python-client为2.6，自动安装selenium4.10
执行示例代码
测试失败

提示如下

D:\Appium01\venv\Scripts\python.exe D:/Appium01/demo1.py
Traceback (most recent call last):
  File "D:\Appium01\demo1.py", line 9, in <module>
    driver = webdriver.Remote(command_executor='http://127.0.0.1:4723/wd/hub',
  File "D:\Appium01\venv\lib\site-packages\appium\webdriver\webdriver.py", line 230, in __init__
    super().__init__(
TypeError: WebDriver.__init__() got an unexpected keyword argument 'desired_capabilities'

场景3:appium-python-client2.6.0+selenium4.3.0 PASS

你应该是先安装selenium4.3.0
然后再安装appium-python-client2.6.0
都是指定版本安装
- 有同学会说，谁会这样安装呢
- 会的，因为你可能是先学selenium(我课程要求是4.3，最新的版本4.10的改进对我们没有太大意义，但底层确实改变了很多)
测试通过

问题说明

TypeError 分析

先看报错

TypeError: WebDriver.__init__() got an unexpected keyword argument 'desired_capabilities'

主要版本信息:
- appium-python-client2.6.0
- selenium4.10
报错行
```
driver = webdriver.Remote
```

Remote是个别名

 from .webdriver import WebDriver as Remote

看WebDriver源码

class WebDriver(
    webdriver.Remote,
    ActionHelpers,
    Activities,
    Applications,
    Clipboard,
    Context,
    Common,
    DeviceTime,
    Display,
    ExecuteDriver,
    ExecuteMobileCommand,
    Gsm,
    HardwareActions,
    ImagesComparison,
    IME,
    Keyboard,
    Location,
    LogEvent,
    Network,
    Performance,
    Power,
    RemoteFS,
    ScreenRecord,
    Session,
    Settings,
    Sms,
    SystemBars,
):
    def __init__(
        self,
        command_executor: str = 'http://127.0.0.1:4444/wd/hub',
        desired_capabilities: Optional[Dict] = None,
        browser_profile: str = None,
        proxy: str = None,
        keep_alive: bool = True,
        direct_connection: bool = True,
        extensions: Optional[List['WebDriver']] = None,
        strict_ssl: bool = True,
        options: Union[AppiumOptions, List[AppiumOptions]] = None,
    ):

__init__中传递了desired_capabilities没有问题

继续分析堆栈

File "D:\Appium01\venv\lib\site-packages\appium\webdriver\webdriver.py", line 230, in __init__
    super().__init__(

继续看WebDriver此处源码

        super().__init__(
            command_executor=AppiumConnection(command_executor, keep_alive=keep_alive),
            desired_capabilities=desired_capabilities,
            browser_profile=browser_profile,
            proxy=proxy,
            options=options,
        )

这里也有desired_capabilities，为何报错了呢

请看WebDriver的继承webdriver.Remote

class WebDriver(BaseWebDriver):
    _web_element_cls = WebElement
    _shadowroot_cls = ShadowRoot

    def __init__(
        self,
        command_executor="http://127.0.0.1:4444",
        keep_alive=True,
        file_detector=None,
        options: Union[BaseOptions, List[BaseOptions]] = None,
    ) -> None:

到这里你发现了，这个__init__里面没有desired_capabilities
注意webdriver.Remote是隶属于selenium的，你此时的selenium是4.10，升级了，可能导致它remove了一些参数

appium-python-client2.11.1+selenium4.10

这是默认组合，要知道selenium也是4.10了，为何没有报错呢？
其调用关系简单分析下

在Remote的__init__中，也支持desired_capabilities，但有如下信息

        # TODO: Remove the deprecated arg
        desired_capabilities: Optional[Dict] = None,
        
        if desired_capabilities is not None:
            warnings.warn(
                'desired_capabilities argument is deprecated and will be removed in future versions. '
                'Use options instead.',
                DeprecationWarning,
            )

后续要移除desired_capabilities
用options替代(模仿selenium)

关键的问题是在于，appium-python-client2.11.1中对父类__init__的调用是不携带desired_capabilities的

        super().__init__(
            command_executor=command_executor,
            options=dst_options,
        )

完整代码片段如下

class WebDriver(
    webdriver.Remote,
    ActionHelpers,
    Activities,
    Applications,
    Clipboard,
    Context,
    Common,
    DeviceTime,
    Display,
    ExecuteDriver,
    ExecuteMobileCommand,
    Gsm,
    HardwareActions,
    ImagesComparison,
    IME,
    Keyboard,
    Location,
    LogEvent,
    Network,
    Performance,
    Power,
    RemoteFS,
    ScreenRecord,
    Session,
    Settings,
    Sms,
    SystemBars,
):
    def __init__(
        self,
        command_executor: Union[str, AppiumConnection] = 'http://127.0.0.1:4444/wd/hub',
        # TODO: Remove the deprecated arg
        desired_capabilities: Optional[Dict] = None,
        # TODO: Remove the deprecated arg
        browser_profile: Union[str, None] = None,
        # TODO: Remove the deprecated arg
        proxy: Union[str, None] = None,
        keep_alive: bool = True,
        direct_connection: bool = True,
        extensions: Optional[List['WebDriver']] = None,
        strict_ssl: bool = True,
        options: Union[AppiumOptions, List[AppiumOptions], None] = None,
    ):
        if strict_ssl is False:
            # pylint: disable=E1101
            # noinspection PyPackageRequirements
            import urllib3

            # pylint: disable=E1101
            # noinspection PyPackageRequirements
            import urllib3.exceptions

            # noinspection PyUnresolvedReferences
            AppiumConnection.set_certificate_bundle_path(None)
            urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

        if isinstance(command_executor, str):
            command_executor = AppiumConnection(command_executor, keep_alive=keep_alive)

        if browser_profile is not None:
            warnings.warn('browser_profile argument is deprecated and has no effect', DeprecationWarning)

        if proxy is not None:
            warnings.warn('proxy argument is deprecated and has no effect', DeprecationWarning)

        if desired_capabilities is not None:
            warnings.warn(
                'desired_capabilities argument is deprecated and will be removed in future versions. '
                'Use options instead.',
                DeprecationWarning,
            )
        # TODO: Remove the fallback after desired_capabilities removal
        dst_options = (
            AppiumOptions().load_capabilities(desired_capabilities)
            if desired_capabilities is not None and options is None
            else options
        )

        super().__init__(
            command_executor=command_executor,
            options=dst_options,
        )

appium-python-client2.6.0+selenium4.3.0

想必分析到此处，你应该盲猜能知道为何这个也PASS了

是因为selenium的版本中webdriver.Remote中是有desired_capabilities的

class WebDriver(BaseWebDriver):
    _web_element_cls = WebElement
    _shadowroot_cls = ShadowRoot

    def __init__(self, command_executor='http://127.0.0.1:4444',
                 desired_capabilities=None, browser_profile=None, proxy=None,
                 keep_alive=True, file_detector=None, options: Union[BaseOptions, List[BaseOptions]] = None):